The aim of this study is to evaluate the apical leakage of MTA (Dentsply Maillefer, Ballaigues, Switzerland) compared to Biodentine when used as retrograde filling materials.

Material And Methods: 70 intact, single-rooted with single-canals teeth were transversally sectioned bellow the cementum-enamel junction
Canals were shaped with Protaper Unisversal System (Dentsply Maillefer, Ballaigues, Switzerland) up to size F2.

Specymens were obturated with warm gutta-percha and resin sealer. Retrograde cavities were prepared.

Teeth were randomly divided into two groups (n = 33) according to the retrograde filling material used: MTA and Biodentine. Two groups (n = 10) were used as positive and negative control.

Specymens were submerged in Rhodamine solution and were cut longitudinally into two halves. Each halph was examined under confocal laser microscope. The area of greater dye penetration was measured in mm to establish the marginal apical leakage of each specymen.

Chi-squared Test was used to statically analyze the results. T-test was used to compare independent samples. Significance level was set at 5%.

**Results:** MTA showed statistically lower apical leakage compared to Biodentine when used as retrofilling material. However, differences between both groups were not statistically significant.

**Conclusion:** Although no group showed a perfect sealing of root-end cavities, both MTA and Biodentine, could be used as retrofilling materials.

EP08

Photodynamic inactivation of intracanal bacteria by light-activation
through dental hard and surrounding tissue in vitro

Fabian Cieplik¹, Andreas Pummer¹, Johannes Regensburger², Tim Maisch², Karl-Anton Hiller¹, Gottfried Schmalz¹,³, Wolfgang Buchalla¹
¹Department of Conservative Dentistry and Periodontology, University Medical Center Regensburg, Regensburg, Germany, ²Department of Dermatology, University Medical Center Regensburg, Regensburg, Germany, ³Department of Preventive, Restorative and Pediatric Dentistry, School of Dental Medicine, University of Bern, Bern, Switzerland

Photodynamic inactivation of bacteria (PIB) may be a supportive antimicrobial tool for use in endodontics. Aim of this *in vitro* study was to evaluate the ability of photosensitizers (PS) to be light-activated through dental hard and surrounding tissues, in order to avoid the use of intracanal optical fibres for application of PIB in endodontics.

A tooth-model was built from a human premolar and two molars arranged in a mixture of Paladur-resin simulating the optical properties of a porcine jaw. The distal root canal of the first molar was expanded for inserting a glass-pipette containing the PS and stationary-phase *Enterococcus faecalis* (EF; ATCC-29212; OD = 0.1). Blue-light absorbing TMPyP and red-light absorbing Methylene Blue (MB) were used as PS in concentrations of 10µM. TMPyP was irradiated for 120s with BlueV (Waldmann; λ = 400-460nm; 20mW/cm²) and MB for 120s with PDT1200L (Waldmann; λ = 570-680nm; 37.8mW/cm²). Irradiation parameters ensured identical numbers of photons absorbed by each PS. Three set-ups were performed: irradiating the glass-pipette only (I), the glass-pipette placed in the single tooth without (II) and with (III) simulated surrounding tissues. Colony forming units (CFU) were evaluated (n ≥ 6; controls: untreated, PS only, light only)

PIB with both PS led to reduction rates of at least 5 log₁₀ steps of EF-CFU for each set-up used, indicating that blue and red light was able to penetrate simulated dental hard and surrounding tissues to activate both PS. Consequently, using TMPyP or MB it might be possible to light-activate intracanal PS from outside the tooth through dental hard and surrounding tissues.

EP09

Push-out bond strength of fiber post to root dentin using three dif-
ferent resin cements

Lourdes Garcia-Gimenez, Vicente Faus-Matoses, Teresa Alegre-Domingo, Vicente Faus-Llacer

University of Valencia, Valecia, Spain

**Objectives:** The aim of this in vitro study was to evaluate the push-out bond strength of three different cements to root dentin in three different thirds of the root canal.

**Methods:** Ninety human intact teeth single rooted lower incisors were transversally sectioned 1mm above the cementum-enamel junction. Canals were prepared with Protaper Universal system (Dentsply Maillefer, Ballaigues, Switzerland) and treated with guttapercha and Top Seal (Dentsply Maillefer, Ballaigues, Switzerland) sealer. Prepared teeth were randomly assigned to one of three groups (n = 30) according to the cement used for post cementation: Core.X Flow (Dentsply DeTrey, Konstanz, Germany); SureFil®SDR™ (Dentsply,G); SmartCem2 (Dentsply,G). After cementation of glass-fiber post, all roots were stored at 100% humidity until testing. For push-out test, 2.5-mm thick slices were produced. Push-out bond strength was assessed at three different levels: cervical, middle and apical using a universal testing machine at a crosshead speed of 0.5mm/minute. Kolmogorov-Smirnov test was used to evaluate the distribution and homogeneity of the data. The values (MPa) were analysed by two-way analysis of variance and Tukey post hoc tests at a significance level of 5%.

**Results:** No significant difference in bond strength was showed between the groups. Core.X Flow and SureFil®SDR™ groups demonstrated statistically lower bonding values in the apical region when compared with the middle and cervical region. SmartCem2 had no significant differences along the root thirds.

**Conclusion:** The resin cements used exhibited similar bond strengths. The lowest bond strength was observed in the apical third for the Core.X Flow and SureFil®SDR™ groups.

EP10

Micro-CT analysis of root canal space of teeth restored with fiber
glass posts

Renata Chalas¹, Marta Jurczykowska¹, Karol Szlazak², Jakub Jaroszewicz², Wojciech Swieszkowski², Krzysztof Jan Kurzydlowski²

¹Department of Conservative Dentistry and Endodontics, Medical University of Lublin, Lublin, Poland, ²Faculty of Materials Science and Engineering, Warsaw University of Technology, Warsaw, Poland

Intracanal posts are commonly used in endodontics, nowadays. However, correct obturation and reconstruction of the root canal space is crucial for the long-term prognosis of a tooth. Micro-computed tomography may provide useful and detailed insights into this procedure. The aim of this study was to evaluate the area/volume of endodontically treated teeth that has been restored with fiber glass posts by means of micro-CT.

**Material and methods:** Single-rooted extracted teeth after endodontic treatment were prepared and restored with XCore&Post System
(Dentsply Maillefer) and rebuild with a CoreX-flow. All teeth were ex-
amined with a SkyScan 1172 micro-CT (Bruker) with a voxel size of 11.0
µm. The 3D reconstructions were performed using NR recon software, and
slices were analyzed using CTAn. DataViewer and CTVol were used to
show the microstructure of restored teeth.

**Results:** The three-dimensional visualization (longitudinal, transverse, sagittal and volume presentation) revealed heterogeneous areas in restored root canals. Air voids were mainly detected in the coronal part of the teeth, and their diameter ranged from 300-1200 µm. These pores were only found in the cement space and were not visible at the cement-dentine interface.

**Conclusion:** 3D investigation of the structure and the position of the fiber post and the cement in the root canal may help to ensure an accurate clinical procedure to avoid pores in the restoration, and to protect from tooth fracture.

EP11

A novel luting resin composite core material

Ahmed Subhy, Luis Rojo, Sanjukta Deb
King's College London, London, UK

**Objectives:** The purpose of this study was to develop novel resin composites tailored to function both as luting medium for post placement and core build up material via inclusion of a methacrylate derivative of eugenol in a bisGMA/TEGDMA resin system. The effect of inclusion of this antibacterial monomer on the physical and mechanical properties were determined and compared with a commercially core material (Clearfil™DC).

**Methods:** The antibacterial monomer eugenyl methacrylate (EgMA) was synthesized and two resin composites formulated with 5 & 10% by weight of EgMA. The base formulation consisted of bisGMA-TEGDMA reinforced with 65% of a hydroxyapatite/zirconia filler. The degree of monomer conversion was evaluated from FTIR spectra and depth of cure, dynamic, static mechanical properties and radiopacity determined.

**Results:** The degree of cure ranged from 65 to 74 %, which was comparable to the Clearfil™ and within acceptable standard. The depth of cure of the experimental composites ranged from 8.3 to 9.8 mm compared to the Clearfil 4.5 mm. The incorporation of 5% EgMA resulted in 114.8 ± 6.8 MPa and 231.34 ± 18.9 MPa average flexural and compressive strength respectively. The radiopacity of the experimental composites (equivalent to ~3mm Al) was superior to that of the commercial core material and sufficiently higher than dentine and enamel to allow efficient diagnosis.

**Conclusion:** The inclusion of EgMA as an antibacterial monomer into commonly used dental methacrylate resin provides a novel approach in imparting antibacterial properties without the inhibitory effect of phenol derivatives.

EP12

The influence of the irrigation protocol in the organic and inorganic radicular dentin composition.

Marta Baron<fnref n="1" />, Nuria Escribano<fnref n="1" />, Maria Linares², Victoria Morales², María Victoria Fuentes<fnref n="1" />, Laura Ceballos<fnref n="1" />

The irrigation solutions not only eliminate bacterial infection when used in root canal treatment, but they can also induce chemical and physical changes in the composition of radicular dentin.

**Objective:** To evaluate the changes of organic and inorganic composition of radicular dentin using different irrigation solutions.

**Materials and methods:** Four single root teeth were shaped with Protaper Universal system (Dentsply Maillefer). Roots were sectioned perpendicularly to the long axis. Three 500 µm thick sections were obtained from each root third, and randomly distributed in different testing groups. GROUP I: NaOCl 5.25% (1 minute) - GROUP II: NaOCl 5.25% (5 minutes) - GROUP III: NaOCl 5.25% (20 minutes) - GROUP IV: EDTA 17% (1 minute) - GROUP V NaOCl 5.25% (20 minutes) - EDTA 17% (1 minute) - NaOCl 5.25% (1 minute). Samples were analyzed by Fourier Transform Infrared spectroscopy (Excalibur 3010 FT-IR, Varian) to determine organic and inorganic components before and after irrigation solution protocol. Data were analyzed by with two-way Anova, and SNK (p < 0.05).

**Results:** In the Group I, II, III, and V, the Amida III and Amida I decreased in apical third.

**Conclusions:** The organic component decreased in the apical third when NaOCl 5.25% was used either in combination with EDTA 17% or not.

Operative Dentistry (OD)

OD01

Effectiveness of optical illusion techniques for anterior diastema closure with one composite resin veneer.

Thomai Katsarou, Maria Antoniadou, Stratis Papazoglou
Dental School of Athens, Athens, Greece

**Aim:** To assess the esthetic effectiveness of 5 techniques for diastema closure between the maxillary central incisors intervening only on one of them with a composite resin veneer.

**Methods:** An acrylic model with 6 natural maxillary anterior teeth having a 2mm diastema between the central incisors was fabricated. Left central incisor #21, was prepared for laminate veneer. Composite veneers were constructed (V0: no veneer, V1: veneer without optical illusion, V2: veneer with centralized interproximal ridges, V3:veneer with curved incisal edges, V4:veneer with grey pigment mesially/distally, V5:veneer with grey pigment on developmental lobes). Digital photos (size a:13,2x17,8cm, b:6,1x8cm) of the restorations, were given for evaluation to 75 persons (n = 25 persons per group of specialists, dental students, and patients) in standardized conditions. Results were analyzed by X² test (a = 0.05), Stuart-Maxuell and Bonferroni Correction test.

**Results:** Method had a significant influence on the assessment of both width and length. The incisor in a lower probability was

<footnote n="1">¹Rey Juan Carlos University, Alcorcón, Madrid, Spain, ²Rey Juan Carlos University, Móstoles, Madrid, Spain</footnote>
assessed as wider in V0 (99,4%, p < 0,001) and longer in V0 (63,1%), V3 (81,5%) and V4 (63,8%) compared to V1. Group and gender had significant influence only on the assessment of length. Students had reduced probability to consider incisor longer (59,6%) compared to specialists and women (60%) compared to men.

**Conclusions:** V0, V3 and V4 are effective when incisor is desired to seem shorter. Patients' perception is reduced compared to that of dentists and students' compared to specialists. Gender interferes in the perception of length.

## OD02

### Closing the Gap: the role of virtual reality in linking preclinical and clinical operative skills

Catherine Snelling

University of Adelaide, Adelaide, Australia

It could be argued that more than any other health practitioner, dental operators require a high level of manual dexterity at graduation. Minimum intervention dentistry has added clinical procedures such as tunnel preparations that require exquisite dexterity, and an increasing number of dentate patients in the elderly population has increased demand for skilful periodontal and endodontic care.

With this evolution of dental care in mind, fledging practitioners must be given the opportunity to nurture operative skills in an environment that allows them to develop confidence and competence before commencing clinical practice on patients. Contemporary dental educators need to design and implement a preclinical program in their courses that scaffold skill development in parallel to knowledge acquisition. Rather than students moving straight across the divide from somewhat 'static' typodonts to 'real-world' mouths, many dental programs are closing the gap with the inclusion of virtual reality technology as a strategic stage in their operative technique courses.

This paper will provide an overview of international trends in the role of virtual reality in dental education. It will then focus on the strategies that have been introduced as part of an evidence-based approach to embedding virtual reality in the School of Dentistry at the University of Adelaide, Australia. Data and outcomes from two years of implementation will be discussed as well as where ongoing work is needed to further close this gap in dental education.

## OD03

### Margin integrity and mechanical properties of selectively excavated and differently restored teeth in vitro

Falk Schwendicke¹, Matthias Kern², Christof Dörfer³, Julia Kleemann-Lübkes³, Uwe Blunck¹, Sebastian Paris¹

¹Department of Operative and Preventive Dentistry, Charité - Universitätsmedizin Berlin, Berlin, Germany, ²Department of Prosthodontics, Propaedeutics and Dental Materials, Christian-Albrechts Universität, Kiel, Germany, ³Department for Conservative Dentistry and Periodontology, Christian-Albrechts Universität, Kiel, Germany

**Objectives:** Selective (incomplete) caries excavation reduces the risk of pulpal complications, but might compromise the mechanical properties or

marginal integrity of teeth or restorations. Different restorative approaches might be required after selective instead of complete excavation. We compared margin integrity, micro-leakage and fracture resistance of selectively excavated and differently restored premolars in vitro.

**Methods:** In 72 extracted human premolars, artificial residual lesions were induced on pulpo-axial walls of standardized cavities. Teeth were restored using one of three bonding systems (OptiBond FL, Clearfil SE Bond, G-aenial Bond) and a fiber-enforced (EverX) or standard hybrid composite (Filtek Z250). After thermo-mechanical cycling, groups (n = 12) were compared regarding their gingivo-cervical margin integrity (proportion of acceptable margins), microleakage depth, and fracture resistance, with statistical evaluation using generalized linear modelling.

**Results:** Margin integrity was significantly influenced by the bonding system (p < 0.001), not the composite (p = 0.105). Proportions of acceptable margins were increased in teeth restored with OptiBond (median [25/75th percentiles]:93[78/100%]) or Clearfil (82[60/94%]) instead of G-aenial Bond (43[15/74%]; p < 0.05). Neither bonding systems nor composites significantly influenced leakage depth in enamel (p = 0.749/0.569) or dentin (p = 0.112/0.909). Fracture resistance was significantly influenced by bonding system (p = 0.008) and composite (p = 0.001), and was higher in teeth restored using OptiBond (mean [SD]:1210[336]N) instead of Clearfil (1007[208]N) or G-aenial Bond (1023[281]N, p < 0.05), and using EverX (1182[314]N) instead of Z250 (979[228]N; p < 0.01).

**Conclusions:** Bonding systems which perform well in completely excavated teeth also yielded good results for selectively excavated teeth in vitro. Using fiber-enforced composites to restore selectively teeth might increase fracture resistance.

## OD04

### Effect of Combining Radiographs and DIAGNOdent with Visual Examination on Detection of Occlusal Caries

Qasem Alomari, Muawia Qudeimat, Mai Khalaf, Yacoub Al-Tarakemah
Kuwait University, Kuwait, Kuwait

The aim of this laboratory study was to evaluate the effectiveness of incorporating radiographs and DIAGNOdent to visual examination on the detection and treatment of occlusal caries. Four examiners examined the occlusal surfaces of 160 extracted posterior teeth. Teeth were examined three times with a one month interval in between. The first examination was visual (V). The second examination was visual with radiograph (VR) and the third examination was visual with radiograph and DIAGNOdent (VRD). Examiners were asked to detect the presence and extent of caries. The examiners were also asked to choose a treatment for each tooth. The examined teeth were later sectioned and the presence of caries was charted. Sensitivity, specificity, area under the curve (Az values), rank correlation coefficient, and McNemar χ² tests were calculated. VR had statistically higher specificity and lower sensitivity than V and VRD. The means of Az values ranged from 0.58 to 0.63 with no statistical difference between the three examinations (p > 0.05). The means of the rank correlation coefficients with histology for detection of dentinal caries were: 0.48, 0.23 and 0.44 using V, VR and VRD respectively. The percentages of teeth correctly treated according to histology were 69.4, 70.0 and 67.5 using V, VR, VRD respectively. There was no difference in the accuracy of treatment decisions between the
three examination points (P > 0.05). The addition of radiographs and DIAGNOdent to visual examination did not have a significant effect on the improvement of the detection and treatment decisions of non-cavitated occluso-dentinal carious lesions.

## OD05

### Airborne-particle Abrasion Is a Minimally Invasive Method to Pretreat Sclerotic, Non-Carious Cervical Dentin

Simon Flury, Anne Peutzfeldt, Adrian Lussi

Department of Preventive, Restorative and Pediatric Dentistry, School of Dental Medicine, University of Bern, Switzerland

**Aims:** To investigate substance loss and bond strength capacity of sclerotic, non-carious cervical dentin after airborne-particle abrasion or diamond bur preparation.

**Methods:** Fifteen non-sclerotic dentin specimens were made from crowns of extracted human incisors of which the labial surfaces had been ground with silicon carbide papers (non-sclerotic control; Group 1). Forty-five sclerotic dentin specimens (n = 15/group) were made from the labial, non-carious cervical root part of extracted human incisors and underwent either no pre-treatment (sclerotic control; Group 2), pre-treatment with airborne-particle abrasion (CoJet System (3M ESPE) and 50 µm aluminium oxide; Group 3), or with diamond bur preparation (40 µm grit size; Group 4). Substance loss after pre-treatment was measured in Groups 3 and 4. Subsequently, Scotchbond Universal (3M ESPE) and resin composite (CeramX (DENTSPLY DeTrey)) were applied on the treated dentin surfaces. The specimens were stored at 37°C and 100% humidity for 24h. After storage, shear bond strength (SBS) was measured and data analyzed with nonparametric ANOVA followed by Wilcoxon rank sum tests.

**Results:** Substance loss (medians) was 19 µm in Group 3 and 113 µm in Group 4. SBS-values (MPa; medians) in Group 2 (9.24) were significantly lower than in Group 1 (13.15; p = 0.0069), Group 3 (13.05; p = 0.01), and Group 4 (13.02; p = 0.0142). There was no significant difference in SBS between Groups 1, 3, and 4 (p ≥ 0.8063).

**Conclusions:** Airborne-particle abrasion and diamond bur preparation restored bond strength of Scotchbond Universal to sclerotic dentin to the level of non-sclerotic dentin, with airborne-particle abrasion being less invasive than diamond bur preparation.

## OD06

### Non-invasive proximal adhesive restoration (NIPAR) compared to infiltration technique for treating initial proximal carious lesions

Marwa Abdelaziz¹, Adele Lodi Rizzini¹, Tissiana Bortolotto¹, Albert Feilzer², ivo Krejci¹

¹University of Geneva, Geneva, Switzerland, ²University of Amsterdam, Amsterdam, The Netherlands

**Objective:** To compare a new technique (NIPAR) to the infiltration technique (ICON).

**Methods:** 13 extracted human posterior teeth with non-cavitated proximal carious lesions were cut vertically to obtain two symmetrical lesions.

Gr.1: half of the paired lesions surfaces (No = 13) were etched with 15% HCl gel (120s) (ICON, DMH, Hamburg, Germany). Gr. 2: the second half (No = 13) were abraded with Al2O3-coated metallic strips and etched with 37% H3PO4 (120s). All samples were then stained with rhodamine isothiocyanate (RITC). After ethanol drying and isolation of the cut surface, Gr. 1 samples were infiltrated with ICON infiltrant (DMG) following manufacturer's instructions. Gr. 2 samples were infiltrated with Scotchbond Universal (3MEspe,MN,USA) for 180s and coated with a thin layer of Tetric flow (Vivadent, Schaan, FL). After light curing, unbound rhodamine was bleached by immersion in 30% hydrogen peroxide (12h). Remaining lesion pores were stained with sodium fluoresceine solution. Samples were observed with confocal microscopy (CLSM, Leica SP5-2P) and the percentage of infiltration (area of resin infiltration/area of total demineralization x100) was calculated using ImageJ (NIH,USA).

**Results:** 11 samples out of 13 showed greater penetration into the lesion for Gr.2 compared to Gr. 1. The mean value of the penetration for Gr.1 was 20.1%, while for Gr.2 it was 40.4%. Statistical analysis (SPSS vers. 21, paired t-test) revealed a significant difference between the 2 groups (p < 0.05).

**Conclusions:** Within its limitation this study shows that using NIPAR represents a valid option for the early treatment of proximal lesions when compared to ICON.

## OD07

### Reasons for placement and replacement of direct restorative materials in Turkey.

Hakan Çolak¹, Çoruh Türksel Dülgergil¹, Ertugrul Ercan¹, Abdülkadir Sengün¹

¹Ishik University School of Dentistry, Erbil, Iraq, ²Kirikkale University School of Dentistry, Kirikkale, Turkey

**Aim:** This study investigated reasons for the provision of direct restorations in postgraduate clinic at the University of Kırıkkale.

**Methods:** This study evaluated 5000 restorative procedures carried out on 1403 (59%female and %41 male) patients. The information recorded reported the patient's age, gender, tooth number, the class of restorations, the restorative material used, and the reasons for placement and replacement of amalgam and tooth-colored restorations. Statistical analysis was carried out using Chi-square test (α = 0.05).

**Results:** Data were obtained on a total of 5000 restorations from 3672 (73,4%) being initial placements and 1328 (26,6%) replacements. The reasons for placement were principally primary caries (88,1 %), non-carious defects (9,3 %) and other reasons (2,6%). Secondary caries was the most common reason for replacement (72% and 38,6% for composite and amalgam, respectively). The second major reason for the replacement restorations was poor anatomic form (21.7%) for amalgam restoration and marginal discoloration for composite restoration. The resin composite was statistically (p = 0.000) the most indicated material (86.7%) for the first time placements.

**Conclusion:** Replacements have been the main reason for performing direct restorations, and the chosen restoration material was resin composite.
## OD08

### Analysis of cyclic thermal stress on restored tooth using finite element analysis

Yoon Lee¹, WooRham Han², Ho-Bum Kwon², Deog-Gyu Seo²

¹Yonsei University Wonju Severance Christian Hospital, Wonju, Republic of Korea, ²Seoul National University School of Dentistry, Seoul, Republic of Korea

**Introduction:** The intake of hot and cold substances in daily life generates cyclic thermal stress to tooth, and this repeated stress may result in fatigue failure. The purpose of this study was to analyze the relationship between cyclic thermal stress and tooth crack formation using finite element analysis.

**Methods:** A maxillary first molar with class I or class II restoration was modelled via CAD-FEM procedure. Thermal load based on in vivo experimental data was applied to class I/II prepared natural tooth without filling material (control) and class I/II gold restored tooth. Stress generated in tooth structure was examined. Predicted fatigue life based on stress analysis was calculated using Basquin's equation.

**Results:** Calculated fatigue life was shorter in gold restored group than in controlled group and class II restored group showed shorter fatigue life than class I restored group. The shortest fatigue life was shown in class II gold restored tooth (3 X 10⁷ years). For all cases, maximum stress was held in cold stimulation.

**Conclusions:** The cyclic thermal stress is a contributing factor of tooth crack formation and the presence of restoration facilitates the fatigue failure caused by cyclic thermal stress.

## OD09

### One year clinical performance of root surface restorations in older adults

Martina Hayes, Cristiane da Mata, Francis Burke, Finbarr Allen

University College Cork, Cork, Ireland

**Objectives:** To compare the clinical performance of three restorative materials in root caries lesions.

**Methods:** A randomized clinical trial was conducted on independently-living older adults (>65 years) in Cork, Ireland. Active, cavitated lesions on root surfaces were identified. Following caries removal they were restored randomly with one of three materials: (1) a packable glass ionomer (Fuji IX GP Extra, GC Corporation), (2) a resin modified glass ionomer (Fuji II LA, GC Corporation) and; (3) a tricalcium silicate based material (Biodentine, Septodont). Six and twelve months after placement the restorations were assessed by a blinded independent examiner according to USPHS criteria.

**Results:** 304 (86 GIC, 83 RMGIC, and 135 Biodentine) restorations were placed in 86 participants. At the time of this interim analysis, 254 restorations in 71 patients have been reviewed at 6 months, and 146 restorations in 41 patients have been assessed at 12 months. The 6 month survival rates were 54.3% for Biodentine, 82.6% for GIC and 91.3% for RMGIC. The 12 month

survival rates were 33.3% for Biodentine, 80% for GIC and 85% for RMGIC.

There were statistically significant differences in restoration failure rates between the three groups at both 6 and 12 months (Chi-square test, p < 0.05). The success rates of GIC and RMGIC were similar but the success rate of Biodentine restorations was significantly lower than the other two materials (p < 0.05).

**Conclusion:** The 6 and 12 month success rates of GIC and RMGIC were similar; however the success rate of Biodentine was significantly lower.

## OD10

### Can reduced-step polishers be as effective as multi-steps on enhancing surface smoothness?

Hande Kemaloglu, Gamze Yildirim, L. Sebnem Turkun

Ege University School of Dentistry, Department of Restorative Dentistry, Izmir, Turkey

The aim of this study was to evaluate the effect of various reduced-step polishers versus multi-steps on the surface roughness of a resin composite. Ninety discs (10 x 2mm) of a nano-hybrid resin composite Tetric N-Ceram (Ivoclar/Vivadent, Liechtenstein) were fabricated in a metal mould covered with Mylar strip and randomly divided into 9 groups (n = 10). Except for the control group (Group 1), all the specimens were first finished with coarse and medium Super-snap discs (Shofu, Japan) and polished with the following systems as recommended by manufacturers: Shiny (Micerium, Italy) (Group 2), Venus Supra (Heraeus Kulzer, Germany) (Group 3), One-gloss (Shofu, Japan) (Group 3), Sof-Lex Spiral Wheels (3M ESPE, USA) (Group 4), Super-snap (fine, superfine) (Shofu, Japan) (Group 5), Pogo (Dentsply, USA) (Group 6), Clearfil Twist Dia (Kuraray, Japan) (Group 7), Rubber cups (Kenda, Liechtenstein) (Group 8). The discs were kept in water for one week before testing. The surface roughness (Ra, µm) of all groups were measured with Mitutoyu SJ-301 (Mitutoyu, Japan) surface roughness tester. Results were statistically analyzed using One-way Anova and Dunnett T3 test at a p < 0.05 significance level.

Significant difference was found among the surface roughness of all groups (p < 0.05). Super-snap, Pogo and Spiral-wheel groups presented similar results to the control group of Mylar strip with smoothest surfaces. These results were significantly different than Shiny, Venus, Clearfil Twist Dia and One-gloss groups (p < 0.05). The group that showed the roughest surface among all was the Rubber cup group (p < 0.05).

All the polishers were donated by their representative manufacturers.

## OD11

### Real bulk restorative technique with a dual cured bulk fill composite and one component adhesive

Tissiana Bortolotto¹, Marwa Abdelaziz¹, Ivo Krejci¹

¹Faculty of Medicine, University Clinic of Dental Medicine, Geneva, Switzerland, ²Faculty of Medicine, University Clinic of Dental Medicine, Geneva, Switzerland, ³Faculty of Medicine, University Clinic of Dental Medicine, Geneva, Switzerland

**Objectives:** Seeking to find a rapid restorative technique for class II cavities, this study aimed to:
1. Evaluate marginal adaptation of a new dual cured bulk fill composite (Fill-Up!, ColtèneWhaledent, Altstätten, Switzerland) in combination with a one component SE adhesive (One Coat Universal, ColtèneWhaledent) in comparison to the original chemically cured adhesive system (Parabond, ColtèneWhaledent)

2. Determine if the use of a chemical activator is necessary for activation of One Coat Universal in combination with FillUp!

## Materials and Methods:

Groups (n = 8):

1. OneCoat Universal with chemical activator

2. OneCoat Universal

3. Parabond

In box shaped bevelled MO cavities, adhesives were applied following manufacturer's instructions. Fill-Up! was injected in one layer, left undisturbed for 30s, and light cured from the occlusal for 20s. Percentages of continuous margins (Mean %CM ± SD) were quantified before / after thermo-mechanical loading (SEM)

**Results:** No significant difference between groups was detected for total marginal length after loading, %CM ranging from 48.2 ± 13.7 to 68.6 ± 8.5 (ANOVA; p > 0.05). On cervical margins (critical area due to maximum distance from curing light), Gr. 1 attained significantly highest %CM (85.0 ± 10.1), followed by Gr. 3 (44.1 ± 27.2). Gr. 2 resulted in poor marginal adaptation (%CM: 10.0 ± 8.8).

**Conclusions:** High %CM were attained in class II restorations filled with a bulk fill dual cured composite and a one component SE adhesive. However, the use of an activator was mandatory to compensate for lack of light in the depth of the cavity.

## OD12

### comparing self-etch adhesives for the infiltration of non-cavitated carious lesions

Marwa Abdelaziz¹, Adele Lodi Rizzini¹, Albert Feilzer², Ivo Krejci¹

¹University of Geneva, Geneva, Switzerland, ²ACTA, Amsterdam, The Netherlands

**Objective:** to compare the efficiency of infiltration of three self-etch adhesives (one or two-component) into natural non-cavitated carious lesions.

**Methods:** 21 extracted human molars and premolars with non-cavitated interproximal lesions were selected. ICDAS code 1-2 was assessed by visual and microscope analysis. Samples were cut vertically across the demineralization (n = 24 lesions). After isolating the cut surface, lesion surfaces were abraded with fine Al2O3-coated metallic strips and etched (H3PO4 37% 120s). Teeth were stained with rhodamine-isothiocyanate (RITC) solution (12h) and dried (ethanol 96% 30s, air-dry 10s). Lesions were randomly divided into three groups and infiltrated with self-etch adhesive systems. Gr.1: one-component One-Coat7.0 (Coltene/ Whaledent AG, Switzerland); Gr.2: one-component Scotchbond Universal (3MEspe,MN, USA); Gr.3: two-component Clearfil Protect Bond

(Kuraray Noritake Dental Inc., Okayama, Japan). In all groups the adhesive was applied twice (180s, light-cured, 60s) and coated with a thin layer of (Tetric flow, Vivadent, FL). After light curing, unbound dye was bleached by immersion in hydrogen peroxide (30% 12h, 37°C). Remaining lesion pores were stained with sodium fluorescein solution. Thin cuts of the teeth were observed with confocal microscopy (LSM510 Meta, Zeiss, Germany) and computer image analysis was performed (ImageJ, NIH, USA) to calculate the percentage of infiltration (resin infiltration area/total demineralization area x100).

**Results:** Infiltration with the three different self-etch adhesives showed similar results. The mean percentage of infiltration was (Gr.1) 27.7%, (Gr.2) 22.7%, (Gr.3) 24.6%.

**Conclusions:** Within the limitation of this in vitro study, one-component and two-component self-etch adhesives are equally suitable for infiltration of natural-caries lesions.

## OD13

### Comparison of conventional vs spectrophotometric methods of shade selection regarding experience

Duygu Recen, Banu Onal, L. Sebnem Turkun, Hazal Cankurt
Ege University School of Dentistry, Izmir, Bornova, Turkey

**Purpose:** The objective was to compare the shade selection ability among dentists with different levels of experience in esthetic dentistry in comparison to a spectrophotometer.

**Methods:** A clinical undergraduate student, a research assistant with 2 years of experience and two restorative dentistry specialists with more than 10 years of experience were included in the study as examiners. The participants were selected from volunteer students of Ege University School of Dentistry (n = 100). All the subjects were healthy with no bleaching history and were caries/restoration free on their anterior teeth. The shade of tooth #11 of all students was taken by the examiners one by one-using Vita Classical (Vita Zahnfabrik, Bad Sackingen, Germany) shade tab. At the end, the research assistant took the shades again with SpectroShade Micro (MHT Optic Research, Niederhasli, Switzerland) device. The color codes obtained were statistically evaluated compared to the device and among them with Wilcoxon Signed Ranks Test with a significance level of .005.

**Results:** The difference in scores among the experienced examiners was not statistically significant. However, the research assistant could guess the shade of the teeth better than the dentistry student (p < 0.05) and as she was familiar with the device, was the only one who could guess the shades similarly to the Spectrophotometer.

**Conclusion:** According to the results of this study, it can be said that conventional shade matching ability is increasing with experience. However for inexperienced dentists, Sepctrophotometer devices may be helpful to confirm the shade selected with classical shade guides.

## OD14

### Microleakage Evaluation of Direct Composite Inlay, Indirect Porcelain Inlay and Teeth Restored with Cad/Cam Systems

Damla Ibrahimov, Ertugrul Ercan
Kirikkale University, Faculty of Dentistry, Kirikkale, Turkey
**Aim:** The aim of this study was to evaluate in vitro edge leakage of inlay applications that were restored with using different methods and materials.

**Materials and Methods:** In this study, class II mesio-occlusal cavities were prepared to 80 caries and restoration free human third molar teeth. The teeth were divided into four groups and 20 teeth in each group. 1. Group: Filtek Ultimate direct composite resin inlays, 2. Group: Lava Ultimate inlays, 3. Group: IPS e.max Press ceramic inlays and 4. Group: IPS e.max CAD inlays were prepared. After finishing and polishing procedures 10.000 thermal cycle between 5 ± 1°C and 55 ± 1°C was applied to all specimens. All samples were suspended in a 0.5 % basic fuchsin solution for 24 hours. After, the teeth were cut longitudinally. Photos of dye penetration scores were recorded at x30 magnification on the computer.

**Results:** According to the results, in occlusal region; lowest microleakage values were identified in e.max CAD and Lava groups, than Filtek and e.max Press groups, respectively. Groups prepared in occlusal regions by using Cad/Cam methods showed lower microleakage values than the other groups and the difference was statistically significant (p < 0.05). In gingival region compared between the groups, there was no significant difference between materials (p > 0.05).

**Conclusion:** When microleakage values compared, CAD / CAM generated inlay groups gave better results; but in cervical regions, no significant difference was determined between different groups. However, further clinical studies are needed.

## OD15

### Evaluation of dentinal tubule occlusion by Nd:YAG and Er:YAG lasers: Real-time measurement of dentinal fluid flow

Inbog Lee, Minho Kim, Ryan Kim

School of Dentistry, Seoul National University, Seoul, Republic of Korea

**Objectives:** The objective of this study was to evaluate the effect of Nd:YAG, Er:YAG lasers and a topical desensitizing agent on dentinal tubule occlusion by measuring real-time dentinal fluid flow and observing the tubule surfaces.

**Methods:** Twenty-four molars were prepared with V-shape cavity at the cervical area, acid etched, water rinsed, blot dried, and treated with 1) Nd:YAG laser; 2) Er:YAG laser; and 3) SuperSeal, a desensitizing agent (n = 8). A real-time fluid flow measuring device (nano-Flow) was used to measure the dentinal fluid flow throughout the procedures. The fluid flow rates before and after the lasers or desensitizing agent application were compared. The surface topography of dentinal tubules after each desensitizing method application was examined using SEM.

**Results:** The dentinal fluid flow varied among the groups. The fluid flow rate was significantly reduced after the lasers or desensitizing agent application (p < 0.05). The reduction of fluid flow rate in SuperSeal group (34.8%) was significantly higher than in Nd:YAG (24.1%) and Er:YAG (20.6%) groups (p < 0.05). There was no statistical difference between two laser groups (p > 0.05). In SEM images, the narrowed dentinal tubules by the melted dentin in the laser groups and by the oxalate crystals in SuperSeal group were observed.

**Significance:** The dentinal fluid flow rate was significantly reduced after the lasers or desensitizing agent application. SuperSeal group exhibited better reduction in dentinal fluid flow rate than did other two laser groups.

## OD16

### 22-Months Survival of Deep Dentin Caries Lesions: A Retrospective Clinical Study

Sukran Bolay, Fatma Dilsad Oz, Ceren Ozge Bicer, Elif Ozturk

Hacettepe University, Ankara, Turkey

**Objectives:** The aim of this retrospective study was to evaluate the long-term clinical survival of stepwise versus complete excavation in deep dentin caries lesions.

**Methods:** One hundred-three patients (35-male, 68-female) with at least one permanent tooth with clinically diagnosed deep dentin caries were included. Inclusion criterias were teeth with deep caries lesions having a radiolucency halfway or more into dentine and pulp vitality but absence of spontaneous pain, positive percussion test, and periapical alterations. The subjects received either stepwise (SW) or complete excavation (CE). The radiological and clinical exams were performed after a mean observation time of 22 months. Success was defined as pulp sensitivity to vitality test and absence of periapical lesions as well as a clinical symptom. Data were statistically analyzed using Kaplan-Meier and Log-Rank (Mantel-Cox) tests (SPSS20.0, α = 0.05).

**Results:** Of the 108 treatments performed, 84 were SW and 24 were CE. Fifty-eight restorations were amalgam, 41 were composite and 9 were resin modified glass-ionomer cement. Mean observation period was 22 months. Survival rates were 91 and 95% for SW and CE respectively after 12 months (p = 0.356). For the SW group, survival rate was 88% at 22 months whereas this rate decreased to 70% at 52 months. At 39 months, survival rate decreased to 88% in CE group. Nine of the failed restorations were glass-ionomer. There was a significant difference between survival rates of glass-ionomer and other 2 restoration groups (p = 0.043).

**Conclusions:** Pulp vitality was not adversely effected by either stepwise or complete excavation after a mean 22 months observation.

## OD17

### Influence of different shade of luting cements on feldspatic and lithium-disilicate veneers of varying thicknesses

Michele Ribero, Allegra Comba, Damiano Pasqualini, Mario Alovisi, Elio Berutti, Nicola Scotti

university of turin, turin, Italy

**Objectives:** The aim of this *in vitro* study was to assess the influence of different luting cement shade on color predictability of feldspatic and lithium-disilicate ceramics. The null hypothesis tested is that the luting cement do not influence the final shade of ceramic, independently from the thickness and the ceramic employed.

**Methods:** 120 composite (Adonis, Sweden and Martina) discs, shade 4, of 2mm thickness were prepared and used as background to simulate natural tooth. 120 ceramic discs (A2-HT) were prepared and divided into 2 groups (n = 60) according to the material used: A) lithium-disilicate B) feldspatic ceramic. Samples of each group were than divided into three subgroups (n = 20) according to the ceramic thickness: 0.6mm; 1.0mm; 1.5mm. Each sample was than applied on the composite background using luting material with different shade: a) no cement; b) Yellow (NX3, Kerr); c) Clear (NX3); d) Milky Bright (Choice2, Bisco); e) A2 (Choice2). The resulting sample shade was assessed using a
spectrophotometer (Spectroshade, MHT) on white and black background. Analysis of variance (p < 0.05) was performed to evaluate the effect of different luting material shade(1), ceramic type(2) ceramic thickness(3) and their interaction on final shade.

**Results:** ANOVA showed that, only with samples analyzed on white background, ceramic thickness influence the final sample shade. Luting material A2 and Milky Bright color seems to statistically influence ceramic shade only when its thickness is 0.6mm. No differences were found between the 2 different ceramics tested.

**Conclusions:** The null hypothesis is rejected since ceramic thickness with some opaque color of cement influences the final shade of translucent ceramics.

## OD18

**A novel protocol for predictable placement of prefabricated veneers.**

Dimitrios Spagopoulos, Efstratios Papazoglou

Department of Operative Dentistry, Dental school, University of Athens, Athens, Greece

Even though the prefabricated veneers promise good esthetics due to their prefabricated surface, they fail to present a predictable clinical outcome. The manufacturing companies of prefabricated veneers propose a single appointment procedure without the ability to realize a mock up, showing the patient the desired final result.

A novel 2-appointment protocol with a laboratory step was designed in order to be able to achieve: (a) a mockup, (b) a tooth reduction guide and, (c) a controlled veneer placement.

During the first appointment, photographic documentation and initial impressions are taken to evaluate the case and create a personalized treatment plan. The size of the prefabricated veneers is selected by applying the Sizing Guide on a stone model. Depending on the clinical situation, a combination of sizes can be used. The selected prefabricated veneers are then adapted to the stone model by minimally preparing the gypsum teeth. After finishing the preparation of the teeth, silicon reduction keys are created for transferring these preparations intraorally. This is a clinical sensitive and time consuming technique, however, it preserves sound tooth structure by reducing only the necessary tooth volume. Consequently, the prefabricated veneers are stabilized on the prepared stone model with wax and silicone transfer keys are fabricated. Finally, the shade for the luting composite resin is selected.

During the second appointment, the mock up is realized first. After patient approval of the designed treatment plan, the rest of the procedure is totally predictable using the aforementioned silicon keys for tooth reduction and veneer placement.

## OD19

**Importance of conditioner on marginal sealing of cavity fillings using Sonicfill™**

Sebastiana Arroyo Bote, Javier Martinez Martinez Osorio

Faculty of Dentistry Barcelona University, Barcelona, Spain

**Introduction:** The development of composites with low polymerization shrinkage and increased depth of cure could help foster the quality of marginal sealing. Nevertheless, the lower effectiveness of self-etch adhesives on enamel could compromise the resistance of the sealing.

**Objective:** The aim of the study was to compare the marginal leakage in class I cavities sealed with SonicFill™ and OptiBond XTR with and without conditioner.

**Material and Methods:** We performed class I cavity in 20 extracted human molars free of caries, divided into two groups A and B:

A Filling with OptiBond XTR and SonicFill™

B Engraved with 37% acid for 15' enamel + filling with OptiBond XTR and SonicFill™

After sealing of the root and storage in artificial saliva, the samples were immersed in methylene blue for 24 hours. After that, the samples were subsequently washed. Finally, a longitudinal cut was performed dividing the sample into two halves that were observed with optical microscope.

**Results:** In order to analyze the results, we defined the following filtration values

0 No filtration

1 Filtration in enamel

2 Filtration in the dentin side wall

3 Filtration in the cavity floor

Statistical analysis shows a significant difference between the two groups, performing better group B.

**Discussion-Conclusion:** Composites with low polymerization shrinkage present a lower stress to polymerization, but it is important to use adhesive with sufficient adhesion to ensure the resistance of the sealing. Results demonstrate that previous engraving of enamel significantly improves marginal sealing in cavities filling with SonicFill™ and OptiBond XTR.

## OD20

**Evaluation of self-adhering materials as desensitizing agents in xerostomic patients with head and neck cancer.**

Roberto Pinna, Giovanni Sotgiu, Simone Dore, Egle Milia

University of Sassari, Sassari, Sardinia, Italy

**Aim:** To evaluate the desensitizing capacity of four different materials to treat dentine hypersensitivity in xerostomic patients due to radiotherapy for head and neck cancer.

**Methods:** A total of 68 patients underwent to radiotherapy were selected for the study. The study was conducted as a split-mouth randomized clinical trial, comparing: Vertise Flow™, Universal Dentine Sealant, Clearfil Protect Bond and Flor-Opal® Varnish. Basal and stimulated salivary flow was recorded for each patient according to European classification criteria (1993). The pain experience was generated by a cold stimulus directly to sensitive tooth surface and assessed using the Visual Analogue Scale (VAS). The response was recorded before the application
of the materials (PRE-1), immediately after (POST-1), at 1 week (POST-2), 4 weeks (POST-3) and 12 week controls (POST-4).

**Results:** The number of patients meeting the inclusion criteria was 24. The mean basal salivary flow rate was 0.24 ml/min (minimum 0.06 – maximum 0.42), while the stimulated rate was 0.54 ml/min (minimum 0.29 – maximum 0.86). All the materials tested produced a significant reduction in the dentine sensibility at POST-1 and POST-2. However, at POST-4, showed a dramatically decrease of performance and reduction of the VAS scores have returned close in a similar manner to those measured at the PRE-1.

**Conclusion:** As a result of this investigation, in xerostomic condition patients all the materials tested produced a reduction of dentine hypersensitivity. However, after 12-week controls, there was no significant difference in the decrease of the VAS irrespective of the desensitizing agent employed.

## OD21

### Does the Silane in Multi-mode Universal Adhesive function to Lithium Disilicate?

Hyunyoung Lee, Byeong-Hoon Cho, Ho-Hyun Son

Department of Conservative Dentistry, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea

**Purpose** Multi-mode universal adhesives (MUA) containing many ingredients were introduced in dentistry. We studied the influence of silane in MUA on the bonding of resin cement to lithium disilicate through microshear bond strength (µSBS).

**Materials and methods** Twenty 12 × 14 × 5mm E. max CAD/CAM specimens for each group were fabricated and sintered. Each specimen was embedded into acrylic resin and polished to 500 grit. The surfaces of specimens were treated as follows. Group A: adhesive not-containing silane (ANS); Group B: saline (S) and ANS; Group C: 4% hydrofluoric acid (HF), S and ANS; Group D: adhesive containing silane (ACS); Group E: 4% HF and ACS. Dual-cure resin cement (NX3; Kerr) was applied and prefabricated composite resin cylinder (diameter 0.8mm; Filtek Z250, 3M EPSE) was placed on the surface. The cement was light-cured for 40 seconds. All samples were stored in distilled water at 37°C for 24 hours, and were submitted to shear testing.

**Result** Bond strengths were significantly different among each groups (p < 0.05) except for Group A and D. The mean µSBS (MPa) were; A: 1.18 ± 1.02; B: 8.85 ± 2.67; C: 26.90 ± 6.92; D: 1.32 ± 0.60; E: 21.36 ± 5.24. The µSBS of Group E was significantly lower than that of Group C. Fracture modes were analyzed: predominantly adhesive in non HF treated groups and cohesive in HF treated groups.

**Conclusion** The silane in MUA seems not to influence on the bonding to lithium disilicate. The surface treatment using HF, silane and adhesive (ANS) is recommended in bonding of resin cement to lithium disilicate.

## OD22

### Tooth-composite interaction of self-adhering flowable composites

Christina Brückner, Hartmut Schneider, Rainer Haak

Department of Cariology, Endodontology and Periodontology, University of Leipzig, Leipzig, Germany

**Purpose:** Evaluation of microleakage and tooth-composite interaction of self-adhering flowable composites.

**Materials and Methods:** Standardized class V restorations were prepared (3 mm incisal-apical, 4 mm mesio-distal and 1.5 mm in depth) at 32 human molars. Per group 8 teeth were restored with Vertise Flow (VF), Fusio Liquid Dentin (FLD), an experimental flowable (EF) and the restoration system Adper Prompt-L-Pop/Filtek Supreme XT Flowable (PLP, control). The teeth were prepared according to laboratory standard, stored in distilled water (24 h, 37 °C) and microleakage (ML, percentage of interface length at enamel/dentin) and tooth-composite interaction were determined by light and electron microscope. Data were analyzed using Mann-Whitney U test (α = 0.0042; Bonferroni adjustment, trend: α < p < 0.05).

**Results:** a) Microleakage formation: At enamel, less ML occurred with VF (10.3 %) and EF (9.0 %) compared to FLD (52.9 %; p = 0.009/p < 0.001) and PLP (82.1 %; all p < 0.001). At dentin, less penetration was found with VF (17.6 %) and FLD (4.4 %) compared to EF (75.2 %; p = 0.01/p < 0.001) and PLP (62.3 %; p = 0.002/p < 0.001).

b) Tooth-composite interaction: Adhesive tags at enamel were verifiable constantly with EF and VF, whereas these occurred irregularly with FLD and PLP. At dentin, tags were detectable with all systems.

**Conclusion:** The current study showed an inverse relation between microleakage formation (sealing) and microretentive anchoring of the restoration to enamel. Based on this, the control system PLP seems to be inferior to the self-adhering flowables.

## OD23

### Composite onlays constructed with semidirect technique in mounted silicone casts

Nektarios-Nikolaos Vasilopoulos, Dimitra Kafetzi, Michalis Diomataris, Sofia Diamantopoulou, Efstratios Papazoglou

School Of Dentistry, National and Kapodistrian University of Athens, Athens, Greece

Patients' demand for aesthetic metal-free restorations in the posterior region is continuously increasing. The evolution in adhesive dentistry has broadened the indication for resin composite materials. The primary disadvantage of composite resin, is polymerization shrinkage in the direct technique. To overcome this important disadvantage two techniques have been developed, the indirect and the semidirect technique. The indirect technique requires two appointments and a laboratory involvement. In contrast, in the semidirect technique the onlay can be prepared chairside in a single visit either conventionally or by the use of computer-aided design/computer-aided manufacturing systems (CAD/CAM).

A modified procedure for the conventional semidirect technique is described here. First the cavity is managed and then alginate impressions of the maxilla and mandible are taken. The impression with the prepared tooth is poured with special very rigid addition type silicon material (Mach-2, Parkell, USA) only in the prepared tooth area including two adjacent teeth. The rest of the impression, as well as the impression of the opposite arch are poured with quick setting mounting gypsum. Afterward, the casts are articulated on a special gypsum-free articulator (MagicArt-2, Alphadent Co, Seoul, Korea). The onlay is fabricated and post-cured using light and heat. The occlusion is first checked on the articulator and then the onlay is bonded into the patient's mouth, followed by the final check of the occlusion and polishing of the restoration.
The use of this technique combines the advantages of the direct and the indirect approach with full control of form, shade and occlusion.

## OD24

### Marginal adaptation of class V cavities prepared with a Quantum Square Pulse Er:YAG laser

Izabella Nerushay, Anastasia Ryabova, Ivo Krejci

University of Geneva, Geneva, Switzerland

**Objective:** To evaluate marginal adaptation of mixed class V composite restorations in cavities prepared with the new highly efficient Quantum Square Pulse (QSP) mode Er:YAG laser (LightWalker, Fotona), compared to diamond bur preparation.

**Methods:** Best laser parameters with the noncontact handpiece were determined in a pretest by SEM micromorphological evaluation of enamel and dentin by varying pulse length, power and water spray settings. 21 extracted caries-free human third molars were subsequently randomly equally distributed into Gr. 1: Laser 300mJ/12Hz; Gr. 2: Laser 300mJ followed by 120mJ/12Hz and Gr. 3: Diamond bur. All cavities were restored with Clearfil SE Bond (Kuraray) and Clearfil AP-X (Kuraray) composite under dentinal fluid simulation. SEM marginal adaptation analysis at 200x magnification was performed on replicas before and after thermo-mechanical cyclic loading (TML).

**Results:** The mean % of "continuous margin" before/after TML in enamel were Gr.1: 86.7/80.6; Gr.2: 95.7/88.6; Gr.3: 96.1/93.1 (ANOVA; $p > 0.05$/$>0.05$) and in dentin Gr.1: 97.3/88.5; Gr.2: 96.7/93.4; Gr.3: 91.6/81.0 (ANOVA; $p > 0.05$/$>0.05$)

**Conclusions:** No significant differences in % "continuous margin" were detected for laser prepared cavities in comparison to bur prepared cavities, both in enamel and dentin, before and after loading. Among the two laser groups, there was a trend towards better marginal adaptation in enamel with 300mJ/120mJ compared to 300 mJ only.

## OD25

### Influence of Carbodiimide Cross-Linking on bond strength stability of universal adhesive to radicular dentin

Guido Gregori

University of Turin, Dental School, Turin, Italy

**Objective:** The aim of this in vitro study was to evaluate the effect of a cross-linker agent (carbodiimide, EDC) used as additional primer for fiber posts cementation to radicular dentin. The null hypothesis tested was that EDC do not influence fiber post bond strength stability overtime when employed with a universal adhesive.

**Methods:** 24 extracted intact single-root teeth were selected, endodontically treated and a 10 mm post-space was then prepared. Samples were randomly divided into 2 groups (n = 12) according to the adhesive protocol: 1) AllBond Universal (Bisco); 2) 0.3M EDC + AllBond Universal. The adhesive was applied with the

etch-and-rinse protocol and EDC was used after phosphoric acid etching for 1 min and prior bonding application. Fiber posts were luted using a dual-cure resin cement (Duo-Link Universal, Bisco). Samples of each group where than divided into two subgroups (n = 6): a) immediate push-out test; 2) 12 months storage in artificial saliva and push-out. To perform push-out test, of the coronal and apical region, teeth were cut in 1 mm-thick slices and pushed until failure with an Instron Machine. Results were statistically analyzed with ANOVA test.

**Results:** ANOVA showed that independently from aging and EDC pretreatment the coronal region showed statistically higher bond strength than the apical one ($p = 0.0001$). Aging, EDC pretreatment and the interactions between them did not improve bond strength.

**Conclusions:** The null hypothesis has to be rejected since EDC did not influence bond strength stability of universal adhesive employed for fiber post cementation, both before and after artificial aging.

## OD26

### Comparison of optical characteristics of resin composite by the different finishing and polishing system

A-Ra Jo, Sung-Eun Yang

Department of Conservative Dentistry, Seoul St. Mary's Dental Hospital, Catholic University of Korea, Seoul, Republic of Korea

**Objective:** Translucency and fluorescence are important factors of esthetic anterior restoration. In composite restoration, finishing and polishing system might have an influence on their optical characteristics. The objective of this study was to compare the translucency and fluorescence of nano-hybrid resin composites after various finishing and polishing systems

**Materials & Methods:** 28 specimens (15mm diameter, 2mm thickness) of nano-hybrid composite (Z350/A2, 3M ESPE) was sorted into 4 groups of various finishing and polishing systems(n = 7); Sof-Lex(SL, 3M ESPE), Enhance/PoGo(EP, Dentsply Caulk), Vetus Supra(VS, Heraeus Kulzer), negative control Mylar strip(CL). Translucency Parameter(TP) and fluoresceence(FL) of specimens was measured using a reflection spectrophotometer (color-eye 7000A) with SCE/SCI geometry under the D65 illumination over white and black backgrounds. The values of TP, FL were measured after thermocycling again, for comparing optical characteristics of resin composite between different finishing and polishing systems.

**Results:** EP group showed the lowest TP value. There was no significant difference between group SL, VS and CL. The Value of TP showed no significant differences($p > 0.05$) in all groups between before and after thermocycling.

CL showed the highest FL before thermocycling. After thermocycling, fluorescence of test group significantly was increased. SL and VS group showed significantly higher FL value compared to EP and CL group.

**Conclusion:** SL and VS system exhibited similar translucency and fluorescence with human dentin. Within the limitation of this study, SL and VS system would be clinically acceptable with regard to optical characteristics.
OD27

Prospective Clinical two year Split-mouth-study comparing
Flowable Composites in Class-V-Restorations

Sabine May<sup>2,1</sup>, Karl-Anton Hiller<sup>1</sup>, Gottfried Schmalz<sup>1</sup>, Wolfgang Buchalla<sup>1</sup>, Marianne Federlin<sup>1</sup>

¹University of Regensburg Dental School, Department of Conservative Dentistry and Periodontology, Regensburg, Germany, ²Private Praxis, Amberg, Germany

**Objectives:** To evaluate the clinical performance of two flowable composites for restoring Class-V non-carious-cervical-lesions (NCCLs), one with (ND: N'Durance Dimer Flow; Septodont), one without (FS: Filtek Supreme XTE Flow; 3M ESPE) phase separation and reduction in polymerization shrinkage stress. The Null-hypothesis was that both composites perform equally regarding clinical quality and survival.

**Methods:** In this controlled, prospective, clinical split-mouth study 50 patients (16male/34female) received one ND and one FS Class-V restoration of NCCLs each in premolar teeth, using Clearfil Protect Bond (Kuraray) as adhesive. The restorations were clinically rated by two examiners using FDI criteria at baseline, 12 and 24 months. Criteria evaluated were surface lustre, staining surface, staining margin, fracture material and retention, marginal adaptation, postoperative hypersensitivity, tooth vitality. Gingival status was evaluated. Non-parametric statistical analyses and chi-square tests were applied (α = 0.05).

**Results:** One ND restoration failed between BL and 12 months. The remaining 49 patients with both restorations under risk participated in all recalls. Median patient age was 49(20-65) years, median PBI at BL was 16% (maximum 29%). All 49 ND and FS restorations were rated clinically acceptable. In one patient, both restorations showed intense hypersensitivity at BL which decreased to normal sensitivity after 12 months. No significant differences for all criteria were recorded between ND and FS at each examination. For each material, no significant differences among BL and 12 and BL and 24mo were detected, except for loss of surface-lustre (BL to 12mo).

**Conclusions:** Within the limitations of the study, the Null-hypothesis (materials perform equally) could not be rejected.

OD28

3-Years clinical outcome of direct pulp capping performed with different resin-based materials

Marco Cuppari, Francesco Petrolo, Giulia Massano, Mario Alovisi, Damiano Pasqualini, Elio Berutti, Nicola Scotti

University of Turin, Dental School, Torino, Italy

**Objectives:** To evaluate the influence of three adhesive resin-based materials in the clinical outcome of direct pulp capping. The null hypothesis is that different resin-based materials do not influence the outcome of teeth with pulp exposure

**Methods:** Sixty patients with one asymptomatic primary carious lesion which showed pulp exposure during cavity cleaning were selected and

included for this in-vivo study. Direct pulp capping was randomly per-
formed with three different materials (n = 20): (G1)self-etch adhesive
system (ProtectBond, Kuraray), (G2)glass-ionomer cement (Fuji IX,
GC) and (G3)light-cured MTA-like material (TheraCal, Bisco), that were
applied on exposed pulp according to the manufacturer's instructions.
Direct restoration with a nanohybrid resin composite (Venus Diamond,
Heraeus Kiltzer) was then performed. Patients were recalled at one week,
six months, 1, 2 and 3 years follow-up. All data collected were statisti-
cally analyzed with a χ² test (p < 0,01).

**Results:** After 3-years of clinical function, in Group 1 teeth were vital at 83,3%, in Group 2 at 66,6% and in Group 3 at 93,3% (χ² = 10,3 on vitality maintenance, greater than Group 1 and 2). Bleeding and pre-operative symptoms were significantly associated to pulpal necrosis, while pulpal exposure was not significantly correlated to pulp capping outcome.

**Conclusions:** Based on the results null hypothesis is rejected, confirming a significant correlation between materials and pulpal vitality preservation. The use of TheraCal seems to significantly influence the clinical outcome of teeth with pulp exposure. Further follow-up controls and an increased number of patients are necessary to confirm the results of this in-vivo study.

OD29

Fracture resistance of endodontically treated teeth. An in vitro
comparison between two post restoration techniques

Paula Gómez-Pérez, Vicente Faus-Matoses, Teresa Alegre-Domingo,
Vicente J. Faus-Llácer

University of Valencia. Master in Restorative dentistry and Endodontics,
Valencia, Valencia, Spain

**Introduction:** Endodontically treated teeth preserve a small amount of residual dentin, increasing the risk of fracture than vital teeth. The aim of this in-vitro study was to evaluate the fracture resistance of endodontically treated premolars restored with single or double-post restoration technique.

**Material and methods:** Seventy extracted mandibular premolars were selected. The specimens were decoronated at the cemento-enamel junction and endodontically treated. The samples were divided in 2 groups (n = 35); one group restored with single-post technique and the other with double-post technique. The fiber posts of Core&Post System (Dentsply DeTrey, Konstanz, Germany) were cemented with composite cement CoreXflow (Dentsply DeTrey, Konstanz, Germany). All teeth were restored with composite restorations and submitted to the fracture resistance test in a universal testing machine until fracture. Data were statistically analyzed using Kolmogorov-Smirnov and Levene's tests and by independent t-test at a significance level of 5%.

**Results:** Double-post restoration technique filled more efficiently oval-
shaped canals, reducing the amount of cement needed to fill the gaps
between the post and dentin. Double-post technique induced a reduction
of root fracture risk than single post-technique.

**Conclusion:** Within the limitations of this study, teeth with double-post restoration may show a reduction of failure loads than those with single-post restorations.
OD30

Fracture resistance of three restoration techniques: An in-vitro comparative study.

Sara Sepúlveda Tendillo, Vicente Faus-Matoses, Teresa Alegre-Domingo, Vicente J. Faus-Llácer

Valencia University. Master in Restorative Dentistry and Endodontics, Valencia, Valencia, Spain

The aim of this in-vitro study was to compare the fracture resistance of endodontically treated premolars with fiber post and posterior reconstruction with core-build-up, bulkfill or incremental technique.

Ninety nine extracted free-decay mandibular premolars were decoronated above 2 mm to cementoenamel junction and endodontically treated. Cans were prepared with a rotatory crown-down technique and filled with thermoplastic technique. Post spaces were prepared leaving 5 mm of the endodontic filling to reach the apex of each canal. The specimens were divided into three groups (n = 33) according to the cement used for post cementation. Group 1: Post cementation with Prime & Bond NT+ Self cure Activator (Dentply, DeTrey, Konstanz, Germany), Calibra (Dentply, DeTrey, Konstanz, Germany) and incremental restoration with resin composite. Group 2: Post cementation with Prime & Bond NT and Surefil® SDR™ (Dentsply, Maillefer, Ballaigues, Switzerland) and bulkfill restoration with Surefil® SDR™. Group 3: Post Cementation and reconstruction with Prime & Bond NT + Self cure Activator and Core-X-flow core-build-up (Dentply, DeTrey, Konstanz, Germany). The standardized cores measure were: 6mm diameter base, 5mm diameter closed-end and 5mm height. The push-out test was performed in a universal testing machine until fracture. The data were analyzed by two-way ANOVA and Tukey post hoc test at a significance level 5%.

Root-filled mandibular premolars restored with direct composite with fiber post by different restoration technique, had similar fracture resistance under static loading.

Although similar fracture resistance results were obtained, Core-build-up materials showed better results compared with other techniques being the most recommended technique.

OD31

Marginal sealing of bulk-fill composite at dentin cervical margin after thermal cycling: evaluation by OCT

Gabriele Ventura¹, Allegra Comba¹, Anna Luganini³, Mario Alovisi¹, Camilla Alovisi², Elio Berutti¹, Nicola Scotti¹

¹University of Turin, Department of Surgical Sciences, Dental School, Piemonte, Italy, ²University of Turin, Department of Surgical Sciences, Clinica Oculistica, Piemonte, Italy, ³Department of Life Sciences and Systems Biology, University of Turin, Piemonte, Italy

**Objectives:** The aim of this in vitro study was a non-invasive evaluation of the marginal sealing to dentin cervical margin of second class cavities after thermal aging using the optical coherence tomography (OCT). The null hypothesis is that there is no

difference in marginal sealing between composites of different viscosity.

**Methods:** 8 intact upper premolars, extracted for periodontal reasons, were selected. A mesio-occluso-distal cavity with cervical margins placed 1mm below the CEJ was performed on each tooth. Samples were then all treated with Scotchbond Universal in etch-and-dry technique. Restoration was performed as follow: a 1mm horizontal layer of bulk-fill composite (Venus Bulk-Fill, Heraeus) was placed over only the mesio-cervical cavity floor and cured for 20sec. Then composite restoration of the cavity was performed with oblique layering of nanohybrid resin composite (Clearfill ES-2, Kuraray). OCT ('Spectralis', Heidelberg-Engineering, Germany) imaging was performed after 24h and 2000 thermocycles. Selected samples were sectioned for interfacial observation by confocal laser scanning microscope (CLSM). Marginal adaptation (percentage) was analyzed on 20 B-scans through each sample. Images were analyzed with the software ImageJ to assess the percentage of marginal gap between composite and cervical margin. Data were statistically analyzed with ANOVA test and significance was set for p < 0.05.

**Results:** Statistical analysis showed any differences in marginal adaptation obtained with Venus Bulk-Fill and Clearfill. Thermal cycling significantly affected marginal integrity of tested composites (p = 0.001). CLSM closely confirmed OCT findings in all samples.

**Conclusion:** The null hypothesis is accepted. Thermal aging significantly affected sealing of composites on dentin margin.

OD32

Comparison of silorane and conventional composites for water sorption and mechanical properties with adhesive coating

Burak Gumustas¹, Begum Guray Efes²

¹Medipol University, Istanbul, Turkey, ²Istanbul University, Istanbul, Turkey

The purpose of this in vitro study was to determine the influence of water sorption on composite resins (3M Siloran, Kerr Sonicfill, 3M Z550, GC Kalore) with or without adhesive coating and its effects on flexural strength, surface hardness, surface roughness. Eight groups each containing ten discs (15mm diameter and 1mm height) and bars (25mm x 2mm x 2mm) made of each composite resin were made according to the manufacturer's instructions. Adhesive coating were applied to the last four group by dentin adhesive (3M Singlebond or 3M Silorane AS). All the composites kept at 37°C for 24 hours and then measured for water sorption, flexural strength, surface hardness, surface roughness. At the second phase of the study, discs and bars were immersed into water for 90 days. Then they were thermocycled for 10000 times and remeasured. Data were subjected to analysis of Oneway ANOVA and Paired sample t test (P > 0.05). Different organic matrix types of the composites caused different water sorption levels. The least water sorption levels were observed at Silorane composite groups. The least solubility levels were observed at Silorane and SonicFill composite groups. The highest levels of flexural strength and surface hardness were observed in SonicFill composite groups. (p > 0.05). Within the limitation of this study, the water sorption seem to affect the mechanical properties of the resin composite. Adhesive coating has a limited water sorption reduction in composite resin.
OD33

In vitro evaluation of the bond strength of indirect composite restorative material to bleached enamel

Isil Dogruer¹, Can Dorter²

¹Istanbul Yeni Yuzyil University, Istanbul, Turkey, ²Istanbul University, Istanbul, Turkey

Although the bleaching agent widely used clinically for a long time, there are some question marks about the effects of the dental bonding and restorative materials. The objective of this study was to investigate the effects of different concentrated bleaching methods on microtensile bond strength of tooth coloured indirect restorations. 20 sound extracted human third molars without any anomaly or restorations were used. Tooth separated into two parts from mesio-distal direction. One surface was used as a control group. After bleaching experiment group with 40% Hydrogen Peroxide (HP), 10% Carbamide peroxide (CP) and were stored for 14 days, total-etch (Kerr Optibond Solo) and self-etch (Kerr Optibond All-in-one) dentine adhesives, luting cement (Nexus 3) and 5 mm. dimension tooth coloured indirect restoration blocks (GC Gradia Indirect) was applied on bleached enamel and unbleached enamel respectively. Microtensile bond strength tests were performed using microtensile test machine at 1mm/min speed until failure. The microtensile value was recorded as mPa. Multiple comparisons were done by the One-way Anova test and Students t test. Significance evaluated as p < 0.05. In both total-etch and self-etch groups, the microtensile bond strength values of HP and CP applied experiment group were significantly higher than control group (p < 0.01). There were no statistically significant differences between HP and CP experiment groups in both total-etch and self-etch groups (p > 0.05). Within the limitation of this study, increasing degrees of porosity in enamel with bleaching agents, it's considered to improve adherence of the resin infiltration.

OD34

Effect of bulk thickness on microhardness of different bulk fill resin composites

Ugur Erdemir¹, Emre Ozel², Fulya Topcu³, Murat Tiryaki¹, Elif Aybala Oktay³, Miyiddin Saypullaev¹

¹Department of Operative Dentistry, Istanbul University Faculty of Dentistry, Istanbul, Turkey, ²Department of Restorative Dentistry, Faculty of Dentistry, University of Kocaeli, Kocaeli, Turkey, ³Department of Endodontics and Conservative Dentistry, Gulhane Military Medical Academy, Ankara, Turkey

**Objectives:** The purpose of this study was to investigate the effect of bulk thickness on top and bottom vickers microhardness values (VHN) of high viscosity bulk fill resin composites.

**Materials and Methods:** Three bulk-fill materials (SonicFill, Filtek Bulk Fill and Tetric N-Ceram Bulk Fill) were evaluated. Seven specimens (n = 7) from each material in different thickness (2,- and 4 mm) were prepared by using a stainless steel mold which is 8 mm in diameter. Tetric N-Ceram Bulk specimens were light-cured for 20 seconds while SonicFill ve Filtek Bulk Fill were polimerized for 40 seconds with a QTH lamp at 850 mW/cm² in one direction. All specimens were stored at 37°C for 24h, before hardness measurement. The microhardness measurements for top and bottom surfaces were performed using a digital vickers microhardness tester (load 200g; dwell time 30 seconds). Three indentations for both

surfaces were recorded near the middle area on each specimens and avaraged. Data were statistically analyzed using Kruskal Wallis test and Tukey HSD post-hoc test (α = 0.05).

**Results:** SonicFill exhibited the highest VHN for both 2- and 4 mm thickness and for upper and bottom surfaces (p < 0.001) while Filtek Bulk Fill the lowest (p < 0.05). Bottom surface VHN values were significantly decreased with increasing bulk thickness (p < 0.05). At 2mm depth, all materials achieved at least %80 of their maximum VHN, but at the 4mm depth any of the tested materials were achieved these results.

**Conclusion:** An increase in bulk thickness has resulted significantly decreased bottom VHN values irrespective of the bulk fill composite.

OD35

Sealing performance of resin composite to pulp chamber floor: evaluation by Optical Coherence Tomography

Alessandro Boaglio¹, Allegra Comba¹, Andrea Coscio¹, Mario Alovisi¹, Camilla Alovisi², Elio Berutti¹, Nicola Scotti¹

¹University of Turin, Department of Surgical Sciences, Dental School, Italy, Turin, Italy, ²University of Turin, Department of Surgical Sciences, Clinica Oculistica, Italy, Turin, Italy

**Objectives:** The aim of this in vitro study was a non-invasive evaluation of the composite resin adaptation to cavity floor in post-endodontic restorations using the optical coherence tomography (OCT). The null hypothesis is that there is no difference in sealing performance of the pulp chamber floor between resins of different viscosity.

**Methods:** 30 intact upper molars, extracted for periodontal reasons, were selected, endodontically treated and filled with gutta-percha. Excess of gutta-percha was entirely removed from the chamber floor and teeth were randomly divided into 3 groups (n = 10) according to the material used for the restoration: Group A: 0,5 mm of flowable composite (Venus Bulk-Fill, Hereus-Kulzer) and stratification of nanohybrid composite (Clearfil Majesty ES-2, Kuraray); Group B: single apposition of flowable composite (Venus Bulk-Fill, Hereus-Kulzer); Group C: stratification of nanohybrid composite (Clearfil Majesty ES-2, Kuraray). Materials adaptation to the cavity was assessed with the OCT ('Spectralis', Heidelberg Engineering, Germany) and images were analysed with the software ImageJ to assess the percentage of marginal gap between composite and chamber floor. Collected data were statistically analyzed with the ANOVA test and significance was set for p < 0.05.

**Results:** Statistical analysis showed a significant better adaptation of flowable composites compared to the traditional packable nanohybrid composites (p < 0.05). No differences were found between group A and B.

**Conclusion:** Within the limitations of an in vitro study we can affirm that the use of a thin layer of flowable composite is recommended as first increment in post-endodontic restorations. Further investigations are necessary to confirm these results.

OD36

Color of conventional glass ionomer restoratives compared to shade guides

Panagiotis Ntovas, Panagiotis Lagouvardos
School of Dentistry, University of Athens, Athens, Attica, Greece
**Purpose:** Selecting the correct shade for glass-ionomer restorative materials can be a challenge in contemporary clinical dentistry. The present study compares the color of conventional glass ionomers to the corresponding tabs of shade guides.

**Materials and Methods:** Three conventional glass-ionomers (Equia Fill/GC EQF, Riva/SDI RIV, Ketac Fill plus/3M-ESPE KTF) and one resin composite (Charisma classic/Heraeus-Kulzer CCL) were selected. Four shades from each material were used (A1, A2, A3, A3.5) to make 20 discoid specimens of 3mm(thickness) by 6mm(diameter) from each material. Three different shade guides were also selected (Vita Lumin Vacuum/Vita-VLV, Vintage Halo/Shofu-VHS, Chromascop/ Ivoclar-Vivadent-CRO). Before color measurements, specimens were hydrated for 24h in water of 37° and a mean of three measurements was recorded for each specimen of material or guide. Measurements were recorded in the CIELAB color space using a portable contact colorimeter (Shade Eye/Shofu). Two way ANOVA tests were performed to estimate significant differences between material shades and corresponding tabs of the guides, in the primary and secondary color parameters (L*, a*, b* and ΔE*), at a significant level of 0.05.

**Results:** ΔE* values were mostly above 3.3 and ranged from 2.3-16.2 units for EQF, 3.6-19 units for RIV and 2.9-17.7 units for KTF. Comparisons among shade guides showed also differences ranged from 6.3-11.5 for VLV, 2.3-9.9 for SVH and 2.8-8.8 for CRO while ΔE* values for the resin CCL from glass-ionomers ranged from 10.0 to 19.0 units. Statistical analysis showed significant differences in ΔE* among materials and shade guides (p < 0.05).

**Conclusions:** Glass-ionomer shades present significant differences from the corresponding shades in all guides. However the differences are higher with the VLC among guides and lower with EQF among brands.

## OD37

### The effect of different solutions on the shear bond strength of repaired leucite ceramics

Aylin Cilingir<fnref n="1" />, Meryem Gulce Subasi², Sevgi Zorlu³, Magrur Kazak⁴, Didem Oner Ozdas³, Solen Gunal⁴

**Objective:** The aim of this study was to evaluate the effect of different solutions on the shear bond strength of repaired leucite ceramics.

**Material and Methods:** Ninety-six ceramic (IPS Empress CAD) specimens were prepared (12x12x2mm). Ceramic surfaces were etched with hydrofluoric acid for 60 seconds. A ceramic repair kit (Ivoclar Vivadent); was applied to the surfaces of ceramics according to the manufacturer's instructions. Samples were randomly divided into 4 groups depending on the repaired composite type (N = 24), (Tetric N Ceram, Filtek Z550, Clearfil Majesty Esthetic, Elite Aesthetic Enamel). Composites used for repair applied in a special cylindrical mould (5x2mm). Composite resins were polymerized by using a LED curing light (Elipar). After polymerization, each specimen was stored in artificial saliva at 37 °C for 24h in an oven (Star Dental). The ceramic-composite repaired

specimens were randomly divided into three subgroups according to the solutions (n = 8).

1. Pomegranate Flavored Mineral Water (Uludağ Frutti)

2. Salad dressing (balsamic vinegar, olive oil, lemon, pomegranate syrup, basil, salt, garlic)

3. Control (Distilled water)

After 24h storage, shear bond strength tests were performed with a universal testing machine (858 Mini Bionix) at a crosshead speed of 1.mm/min. Data were statistically analysed with ANOVA and Tukey HDS tests.

**Result:** Tetric Nceram showed the highest shear bond strength in control groups (p < 0.01, p < 0.05). Tetric Nceram showed higher shear bond strength than Filtek Z550 in salad dressing group (p < 0.05).

**Conclusion:** Different composites and solutions have influence on the shear bond strength of repaired ceramics.

## OD38

### Effect of pre-treatment of hybrid CAD-CAM blocks on shear bond strength with self-adhering resin cements.

Christina Boutsiouki, Kosmas Tolidis, Paris Gerasimou
Aristotle University of Thessaloniki, Thessaloniki, Greece

**Introduction:** Resinous cements are the material of choice for cementing indirect composite and ceramic restorations. However, there are no specific guidelines concerning pre-treatment of hybrid resin-ceramic CAD-CAM blocks. Purpose of the study was to test the effect of CAD-CAM block surface pre-treatment on the shear bond with self-adhering resinous cements.

**Materials:** 24 groups (n = 10) were formed according to i) type of block [Lava Ultimate, 3M-ESPE(L) or Shofu Experimental Block, Shofu (S)], ii) type of cement [RelyX Unicem, 3M-ESPE (R) or BeatiCem SA, Shofu (B)] and iii) surface pretreatment [none (CL), sandblasting (S), tribochemical coating (Cojet, 3M-ESPE) (C), silane (SL), hydrofluoric acid + silane (HF + SL), Scotchbond Universal Bonding Agent, 3M-ESPE (U)]. Specimens were manufactured with a circular bonding area of 16,61 mm2. Standardised Ultratester machine (Ultradent) was used at a cross-head speed of 0.5mm/min.

**Results:** Shear bond strength results in MPa (mean/SD) are: LR-CL (12.89/3.54), LR-S (15.86/4.96), LR-C (17.2/1.46), LR-SL (14.23/3.67), LR-HF + SL (13.13/2.14), LR-U (17.88/5.61), SR-CL (4.91/2.01), SR-S (12.83/1.26), SR-C (11.45/4.23), SR-SL (13.76/4.77), SR-HF + SL (20.11/6.95), SR-U (13.56/4.9), LB-CL (12.37/2.14), LB-S (17.09/1.89), LB-C (20.47/1.59), LB-SL (10.98/1.01), LB-HF + SL (15.37/2.28), LB-U (16.39/1.53), SB-CL (4.19/1.51), SB-S (13.48/1.31), SB-C (14/1.28), SB-SL (9.15/1.1), SB-HF + SL (19.98/5.98), SB-U (9.48/1.16). In total, more cohesive failures in blocks (51 %) are recorded, followed by adhesive (37.5%). Statistically significant differences are exhibited in comparison to the control groups for block S.

**Conclusions:** When bonding to hybrid CAD-CAM blocks with self-adhering resinous cements, it is advised to pre-treat the block surface as follows: with S, C or U when bonding to Lava blocks and with HF + SL when bonding to Shofu Experimental blocks, regardless the cement.

<footnote n="1">¹Trakya University Faculty of Dentistry Department of Restorative Dentistry, Edirne, Turkey, ²Istanbul Aydin University Faculty of Dentistry Department of Prosthodontics, Istanbul, Turkey, ³Istanbul Aydin University Faculty of Dentistry Department of Pedodontics, Istanbul, Turkey, ⁴Istanbul Aydin University Faculty of Dentistry Department of Restorative Dentistry, Istanbul, Turkey</footnote>
OD39

Have French dentists implemented recent concepts in cariology into
everyday practice for occlusal caries lesions?

Sophie Doméjean¹, Stéphanie Léger², Marie Maltrait¹, Ivar Espelid³,
Anna Tveit³, Stéphanie Tubert-Jeannin¹

¹UFR d'Odontologie, EA 4847, Centre de Recherche en Odontologie Clinique, Clermont-Ferrand, France, ²Univ Blaise Pascal, Département de Mathématiques, Clermont-Ferrand, France, ³Faculty of Dentistry, University of Oslo, Oslo, Norway

**Objective:** Management decisions for occlusal carious lesions were in-
vestigated in 2012 using a questionnaire survey among French dentists.
Restorative thresholds and management of questionable lesions were de-
scribed and compared to guidelines from recent scientific literature.

**Methods:** A questionnaire developed by Espelid et al. was sent by mail to a random sample of 2,000 French dentists in 2012.

**Results:** Response rate was 41.9% (838 respondents).

**Restorative Threshold:** 39.3% of the respondents would place a restora-
tion for a lesion confined to enamel, 54.7% for a lesion at the enamel-
dentin junction and 6.0% for a lesion in the outer 1/3 of dentin or deeper.

**Diagnosis:** based on a photograph showing an occlusal surface, 40.3% of the respondents diagnosed an enamel lesion, 10.1% a dentinal lesion, 32.3% a sound surface while 14.8% were uncertain. The management strategies proposed were a non-invasive management, a minimally invasive restoration or a restoration comprising all pits and fissures for respectively 54.6%, 33.4% and 12.0% of the respondents for whom diagnosis was uncertain (n = 114).

The present results show that French dentists have not implemented the recent concepts of caries management into practice. Indeed, restorative strategies should be limited to the treatment of carious lesions reaching the middle 1/3 of the dentine and/or with definitive cavitation in the overlying enamel. Moreover, evidence supports nowadays the use of non-invasive management of occlusal non-cavitated or questionable lesions.

**Conclusion:** More efforts are needed to enhance the dissemination, ac-
ceptance and use of the concepts of Minimal Intervention in cariology for
French dentists.

OD40

Biocompatibility of a new fiber-reinforced composite: an in-vitro
study

Lina Dimosiari, Fany Ziouti, Elisabeth Koulaouzidou

Aristotle University of Thessaloniki, Thessaloniki, Greece

**Introduction:** A new fiber-reinforced composite (GC everX Posterior™) was designed to be used as dentine replacement, in conjunction with a conventional composite layer used as enamel replacement. The material is proposed to prevent and stop crack propagation through the filling, via the reinforcement provided by the fibers and is marketed as an economic alternative for chair-side restoration of extensive cavities.

**Materials and Methods:** The purpose of this study was to determine the cytotoxicity of the new fiber-reinforced composite restorative material (GC everX Posterior™) against a fibroblastic cell line. MRC5 cells were grown as monolayer cultures at 37°C in an atmosphere containing 5%CO₂ and 100% relative humidity. The culture medium was Dulbecco's modified medium supplemented with 10% Fetal Bovine Serum and antibiotics. Extracts were obtained from 24h and 10day incubations of composite specimens in cell culture medium at 37°C. The cells were exposed to serial dilutions of the original extracts for 24h, 48h and 72h. Complete medium was used as control. The cytotoxic effect was determined, using the modified colorimetric sulforhodamine B assay, in reference to controls. Statistical analysis was performed with ANOVA/post-hoc tests at p = 0.05.

**Results:** 24h and 10d extracts from the tested composite reduced cell viability after 24h, 48h and 72h of exposure and the effect was concentration- and time- dependent.

**Conclusion:** The tested fiber-reinforced composite showed a potency of reducing viability of cells in vitro

OD41

Influence of DCC in ethanol-wet bonding technique on bond strength
to radicular dentin

Nicola Scotti¹, Carlotta Giuliano¹, Laura Sponzilli¹, Annalisa Mazzoni²,
Lorenzo Breschi², Valeria Angeloni³

¹University of Turin, Turin, Italy, ²University of Trieste, Trieste, Italy,

³University of Bologna, Bologna, Italy

**Objective:** The aim of this *in vitro* study was to evaluate the effect of a cross-linker agent (DCC) used in addition to ethanol in ethanol-wet bonding technique for fiber post cementation to radicular dentin. The null hypothesis tested was that DCC do not influence immediate fiber post bond strength when employed with ethanol.

**Methods:** 18 extracted intact single-root teeth were selected and endodontically treated. A 10mm post-space was prepared with dedicated drills and etched with 37% phosphoric acid. Samples were randomly divided into 3 groups (n = 6) according to the dentin pre-treatment procedure: 1) water-wet bonding: post space irrigation with distilled water for 60sec; 2) ethanol-wet bonding: post space irrigation with ethanol for 60sec; 3) ethanol-wet bonding with DCC: post space irrigation with 0.5M DCC in ethanol for 60sec. Adhesive (AllBond3, Bisco) was, than, applied following manufacturer instruction, and fiber posts were luted with Duo-Link Universal (Bisco) and cured for 40sec. To perform push-out test of the coronal and apical region, samples were cut in 1mm thick slices and pushed until failure with an Instrom Machine. Results were statistically analyzed with ANOVA test, and statistical significance was set for p < 0.05.

**Results:** ANOVA showed that both regions had comparable results for group 2 and 3, while for water-wet bonding the coronal region performed significantly better (p = 0.0001). No differences were found between the three pre-treatment techniques considering the region.

**Conclusions:** The null hypothesis has to be accepted since DCC did not influence immediate bond strength to radicular dentin when applied with ethanol.
## OD42

### Assessment of the Accuracy and Repeatability of Shade Taking using Visual and Digital Shade Guides

Eman Mottaleb, Wei- Ming Tay, Chris Louca, Albert Leung, Robert Blizard
*Eastman Dental Institute, London, UK*

**Objective:** To investigate differences in accuracy and repeatability of shade taking using VITA Classical™ (VC), VITA Linearguide 3D-Master™ (LG) and VITA Easyshade Advance 4.0™ (ESA) shade guides; and whether 3D shades can be converted to Classical without affecting mean accuracy.

**Methods:** 36 participants identified the shades of VC tabs using the VC and LG guides under standardised conditions. This study was repeated using the ESA. 3D shades were converted to Classical shades using four conversion tables.

**Results:** ESA had a greater mean accuracy than visual guides (VC and LG guides combined) (F = 10.95 p = 0.02). There were significant differences between the methods used in this study of recording accuracy (F = 3.03 p = 0.032). Greater accuracy was seen with Classical than with converted 3D shades. There were significant variations of the mean accuracy results between ESA and visual guides. These variations depended on whether classical or 3D values were recorded, and on which 3D to Classical conversion table was applied (F = 3.895 p = 0.11). Repeatability for ESA was better than for visual guides; ESA was 90% (95% CI 84%, 95%) and the visual guides were 45% (95% CI 36%, 53%).

**Conclusions:** *In vitro* ESA has greater accuracy and repeatability than VC or LG guides. The mean accuracy of the results was affected by converting 3D to Classical shades. These issues are very important to clinical dentistry. Further research is required to compile more consistent conversion tables between 3D and Classical shades. A wider range of ceramics and composites should be made available in 3D shades.

## OD43

### Resin infiltration of non-cavitated proximal caries lesions: a systematic review

Ermeline Daniel¹,², Elodie Savard¹,², Roddy Kheng¹,², Elisabeth Dursun¹,²
*^Paris Descartes University, Paris, France, ^A. Chenevier Hospital, Créteil, France*

**Introduction:** To arrest non-cavitated proximal carious lesion progression, a new procedure has been recently developed: the infiltration of enamel micropores by a resinous material, to create the diffusion barrier inside the lesion, replacing lost mineral with resin. This technique is between the prevention therapy (remineralization) and the invasive restorative dentistry (even minimally). The aim of this study was to perform a systematic review of the published literature concerning the caries infiltration.

**Methods:** An electronic search on the PubMed database was attempted to identify all relevant in vitro, in situ and in vivo studies on the proximal caries infiltration and on the shear bond strength to resin-infiltrated enamel. Papers published in English were selected after a critical review of theirs titles, theirs abstracts and finally theirs full texts.

**Results:** The initial search found 184 eligible papers and finally 30 were included in this systematic review. The articles allowed to determine the justification of each protocol step, to optimize the resin penetration in the body of the carious lesions and inhibit its progression (the acid type and concentration; the resin type, duration and number of applications). Other articles allowed to discuss the opening possibility to broader indications (for cavitated lesions) and to underline some unstudied steps of the protocol.

**Conclusion:** The infiltration of subsurface lesions with low-viscous light-curing resins is an extremely conservative approach. Only three clinical studies during one and three years were performed. This technique is very promising but has to prove itself in the long term.

## OD44

### The effect of a bulk-fill base on the clinical survival of direct posterior composite restorations

Colin McGuirk, Fariha Hussain, Brian Millar
*KCL, London, UK*

**Introduction:** Direct composite restorations are increasingly popular for the restoration of posterior teeth. Efforts have been directed at simplifying composite placement techniques without compromising the degree of cure or polymerisation contraction stress. A flowable material (SDR, Dentsply) claims to allow bulk-placement and curing whilst minimising polymerisation contraction stress by utilising a flexible polymerisation process. The aim of this study was to compare composite restorations performed with and without an SDR base.

**Methods and Materials:** A retrospective analysis was performed to compare restorations placed by different techniques. Subjects in Group G received restorations placed according to conventional layering techniques using a nano-hybrid composite (G-aenial, GC). Subjects in Group S received a bulk-fill base using SDR (Dentsply) with a conventional composite outer shell (G-aenial, GC). Data regarding survival, mode of failure and post-operative sensitivity was recorded and analysed.

**Results:** In total 54 Group S restorations and 71 Group G restorations were followed for a minimum of 24 months. Group S had a 92.6% survival and Group G had 93%. Group S was more prone to failure by tooth fracture (p=0.033). In both groups failure was more likely in larger cavities as measured by number of surfaces (p<0.001) and the need for cuspal coverage (p=0.004).

**Conclusion:** The different techniques appear to provide similar levels of survival in the short term. The mode of failure differs between the groups; teeth restored with a bulk-fill SDR base experienced significantly more tooth fractures than the conventional composite group.

## Preventive Dentistry (PD)

### PD01

### Calcium Therapy Preserves Periodontium and Dentition

Mark J. Manhart DDS, Srijita Sen-Crowdhry MD, Kim Truka DDS, Thomas B Steg DDS, James Rezac DDS, Derek Golding DDS, Suzan Hahn DDS
Calcium Therapy Inst., Omaha NE 68114, USA

It is evident that Calcium Therapy consilience is quite high. It fits well with mediating the angiogenetesis upon periodontal tissue invasion and metastasis. Dentists have used this high-impact preventive protocol for half a century. This paper affirms the hard data: thousands of calcium treatments have rendered a more complete diagnosis, preserved granulation tissues, oral bone and the dentition.

**Materials & Methods:** The calcium compounds utilized provide long-term, non-invasive, reliable clinical benefits in all dental fields. On-site and full-mouth timed-release calcium materials are administered to the oral cavity that control acute and chronic inflammations and bacterial colonization for days, weeks and months.

**Results & Discussion:** When oral anaerobic bacteria become rampant, a dramatic breakdown of the oral cavity ensues. For over five decades nearly every patient with minor gingival infection to "hopeless" periodontosis has undergone Calcium Therapy. Within minutes the minimum bacterial concentrations and inflammatory markers show improvement without surgery or anesthesia. The intense in-office therapy can be sustained indefinitely, even for antibiotic sensitivity patients. The toxic invasion is "turned off" and oral tissues calmed. In one simple monthly application blood serum calcium levels elevate and persist for weeks and can be safely maintained for years.

**Conclusions:** While calcium material investigations remain of indiscriminate disinterest to dentistry, Calcium Therapy has replaced periodontal surgery completely. The direct-site therapy rapidly manifests tremendous control over inflammatory outbreaks. Its conservative practicality improves diagnostic protocol, revitalizes the process of wound healing, preserves both the peridontium and dentition, and does no harm while providing and supporting excellent dental restoration.

## PD02

**A novel hand-held reflectometer to quantify enamel erosion: correlation with surface microhardness and calcium release.**

Thiago S. Carvalho, Tommy Baumann, Ekaterina Rakhmatullina, Adrian Lussi
University of Bern, Bern, Switzerland

This study aimed at assessing initial in vitro enamel erosion with a novel hand-held reflectometer, and to correlate the findings with standardized laboratory methods: surface microhardness and chemical analyses of calcium. A total of 120 human enamel specimens were ground, polished, and randomly distributed into 6 groups. Initially, we measured enamel surface reflection intensity (SRI) with the novel hand-held reflectometer, and surface microhardness (SMH) with a Knoop hardness machine. The specimens were individually eroded (10 ml; 1% citric acid; pH 3.6, 25 °C) for 1, 2, 4, 6, 8, or 10 min (20 specimens/group). After erosion, we measured final SRI and SMH, and calculated the loss of SRI and SMH in percentage. Total amount of calcium released by each specimen to the citric acid was also analyzed with an atomic absorption spectrometer. Kruskal-Wallis tests were used to analyze the effect of erosion time on SRI, SMH and calcium release, and Spearman's Rank correlation was performed between SRI and SMH, as well as between SRI and calcium release. Longer

erosion times caused greater loss of SRI (p < 0.001), greater loss of SMH (p < 0.001), and greater calcium release (p < 0.001). A significant correlation was observed between SRI and SMH (r = 0.79; p < 0.001), and between SRI and calcium release (r = 0.70; p < 0.001). The moderate to strong correlation observed between SRI and the two standardized methods shows that the hand-held reflectometer can be considered as a potential tool to assess initial enamel erosion.

## PD03

**In Vitro Monitoring of the Erosion Progression by a New Optical Device**

Julia Kozik, Thiago Saads Carvalho, Adrian Lussi
University of Berne, School of Dental Medicine, Berne, Switzerland

**Aim:** The main objective of this study was the validation of a recently developed optical device for the detection of different stages of erosion on enamel. Another goal was to assess if the optical device can measure the preventive effect of a tin-containing (Sn²⁺-containing) solution on enamel erosion.

**Material and methods:** Enamel samples (n = 30) were placed in 3 different treatment solutions: 1) tap water (control group C, n = 10), 2) NaF-solution (group F, n = 10) and 3) Sn²⁺-containing solution (group SF, n = 10). Enamel erosion was induced by incubating the samples in 0.65% citric acid (30ml; pH = 3.6) for a total of 1, 2, 4, 6 and 8 min. Surface reflection intensity (SRI) was measured before and after each erosive challenge. In addition to this optical method, erosion quantification was performed by surface microhardness (SMH) and calcium analyses.

**Results:** The optical assessment of erosion showed an exponential reduction of SRI throughout the whole experiment in all groups. The final percentage SRI values in group SF were significantly higher than in the other groups, showing significant protection in group SF. The SMH values revealed significant differences between all groups, where group C showed greatest loss of hardness and group SF the least loss of hardness. No significant difference was observed in the total amount of calcium release between the groups. Calcium release, however, showed a satisfactory negative correlation to SRI (r² = -0.61).

**Conclusions:** Monitoring of the SRI can be applied to quantify initial erosive stages. The Sn²⁺-containing solution presented better protection of enamel against erosion than the other groups.

## PD04

**Fluoride varnish versus tray application for head and neck cancer patients' caries prevention**

Melanie Nasseripour¹, Siham Khoulane¹, Geraldine Lescaille¹, Marie-José Javelot¹

¹La Pitié-Salpêtrière Hospital, Paris, France, ²Paris 7 University, Paris, France

**Introduction:** Due to radiotherapy-induced caries, head and neck cancer patients have systematic fluoride application protocol using trays. Our study will evaluate the efficacy of fluoride varnish as an alternative to this protocol.
**Methods:** The double-blinded randomized clinical trial at La Pitié Salpêtrière Hospital will include patients 18 years and older, diagnosed with head and neck epidermoid carcinoma and treated with external radiotherapy. The control group is treated with fluoride trays, the test group with varnish. The clinical and radiological follow up and fluoride renewal is done every 3 months for 24 months.

**Results:** Five of these patients were included in our preliminary study. Clinical and radiological exam were conducted at baseline, 3, 6, and 9 months. Fluoride varnish was used at each visit. The findings were imported into Excel and cariogram®. Despite the established xerostomia no new caries developed at study intervals.

**Conclusion:** Our preliminary study confirms as in scientific litterature that fluoride varnish application is clinically efficient, non patient-compliance dependent, applicable despite limited mouth opening, and non-irritating oral mucosa.

## PD05

### A national pilot study comparing prevalence of caries measured with DMF vs ICDAS in Senegal

Adjaratou Wakha AIDARA<sup>1,2</sup>, Fatou LEYE-BENOIST<sup>1</sup>, Denis BOURGEOIS<sup>2</sup>

<sup>1</sup>Cheikh Anta Diop University, Dakar, Senegal, <sup>2</sup>Claude Bernard Lyon 1 University, Lyon, France

**Aim:** This pilot study has for main objective to measure the applicability and the utility of ICDAS index in a context of prevention in developing countries. Dental caries prevalence was evaluated among schoolchildren using DMF (WHO basic method) vs. ICDAS index in Senegal.

**Materials and method:** A representative stratified random cluster sample of 677 primary and college schoolchildren aged 12 and 15 years was examined for caries prevalence. The clinical examination was conducted in two steps for each groups. The investigator proceeded at first to the reckoning of the number of teeth decayed (D), missing (M) or filled (F) according to the WHO basic method. Then, after cleaning and drying all teeth, a two-digit ICDAS code was used to record data at each dental surface.

**Results:** The caries prevalence (96%) was higher than expected in Senegal. ICDAS index provides 43% moreover information than DMF. The need for prevention (ICDAS1: 66%/72% and ICDAS2: 54%/58%) and interception (ICDAS3: 40%/42% and ICDAS4: 31%/33%) were higher than the need of curative treatment (ICDAS5: 18%/23% and ICDAS6: 27%/33%) respectively among primary and college schoolchildren.

**Conclusion:** Preventive programs are urgently needed in Senegal. It's necessary to lead epidemiological studies in other African countries for determining caries prevalence using the ICDAS criteria to harmonize oral health regional planning.

## PD06

### First Iberian Clinical Practice Guideline for the prevention and non-invasive treatment of dental caries

Elias Casals-Peidró<sup>1,2</sup>, Mari Angeles García-Pereiro<sup>3,4</sup>

<sup>1</sup>Institut Català de la Salut, Granollers (Barcelona), Spain, <sup>2</sup>Sociedad Española de Epidemiología y Salud Pública Oral (SESPO), Madrid,

Spain, <sup>3</sup>Badalona Serveis Assistencials, Badalona (Barcelona), Spain,

<sup>4</sup>Universitat de Barcelona, L'Hospitalet de Llobregat (Barcelona), Spain

**Introduction:** Health professionals recognize the difficulty of identifying the most appropriate care and recommendations to be given to their patients due to the growing body of literature demonstrating clinical success to prevent dental caries. A clinical practice guideline (CPG) is a useful tool in helping health professionals looking for a summary of evidence-based recommendations and activities in an schematic format.

**Methods:** The Spanish Society of Oral Epidemiology and Public Health (SESPO) brought together experts from Spain and Portugal to develop a CPG to promote the prevention and non-invasive treatment of dental caries according to the best scientific evidence available. Results: Firstly, other national CPG regarding dental caries were evaluated. Secondly, the most valuable research was identified in the form of clinical trials. Thirdly, its applicability to Spain and Portugal was evaluated. Two different caries risk levels were stablished (high/low) and two age categories (from 0 to 5 year old/from 6 years old). The GPC introduces to already available tools to assess caries risk (Cariogram, Caries Risk Semaphore, Cambra questionaires) using tree diagrams and to the diagnosis of caries lesions. One age and risk is stablished, recommendations are given regarding the use of self-applied fluoride and non-fluoride products and also which professional care should be given. All recommendations for high-risk groups are always additional to recommendations for low risk.

**Conclusions:** This guide stablishes recommendations for the prevention and non-invasive treatment of dental caries reflecting the current philosophy of monitoring caries disease throughout life.

## PD07

### The wettability of different adhesive systems in superficial and deep dentine

Derya Merve Halaçoglu, Duygu Tuncer, Zümrüt Ceren Salman, Neslihan Arhun

Baskent University, Ankara, Turkey

The aim was to determine the wettability of different types of adhesive systems in superficial and deep dentine.

**Materials and Method:** 24 molar teeth were cut in bucco-lingual direction to produce deep(remaining dentine thickness 1mm far from the pulp) and superficial dentine(dentine layer adjacent to enamel) on buccal and lingual surfaces, respectively. Each half of the teeth were used(n = 48). Dentine specimens were ground wet with 600-grit silicon carbide abrasive paper and were divided into four groups(n = 12): All-Bond-Universal(etch-and-rinse)(AU), All-Bond-Universal(self-etch)(AS), Clearfil-SE-Bond(self-etch)(CSE) and Single-Bond-2(etch-and-rinse)(SB). 3 consecutive contact angle measurements were obtained during the application of the adhesive systems: 1.3µl drop of distilled water on prepared dentin; 2.Droplet of the adhesive resin; 3.Distilled water after polymerization of the adhesive. Data were subjected to analysis of variance for repeated measures among the groups(p < 0.05).

**Results:** There was no significant difference between deep and superficial dentin for all measurements(p < 0.05). In 2.measurement, CSE was significantly different from AS and AU in both dentin groups. In 3.measurement, CSE bond group was
significantly different from other adhesive systems in both dentin groups($p < 0.05$). All of the adhesive systems except CSE increases the wettability of the bond after primer application but decreases the wettability of the distilled water after bond application($p < 0.05$) reaching the first prepared state of the dentin in both dentin levels.

**Conclusion:** Adhesive system choice is not correlated with the depth of dentin; however different adhesives may affect the wettability of the dentin substrates.

## PD08

### The Relation Between Caries Risk Levels and Salivary Immunoglobulins Of Individuals Aged 21-23

Aysegul Kaya¹, Tijen Pamir¹, Necil Kutukculer²

¹Ege University School of Dentistry, Izmir/ Bornova, Turkey, ²Ege University School of Medicine, Izmir/ Bornova, Turkey

**Purpose:** This study aimed to identify high or low caries risk levels of the individual ages between 21-23 years and to associate their salivary IgA, sIgA and IgG with the caries risk.

**Materials and Methods:** Sampling frame of this study was composed of the students (ages between 21-23 years) from Ege University, Faculty of Agriculture, İzmir, Turkey. 87 (32 female, 55 male) participations out of 1960 volunteers orally examined were enrolled in the study. Cariogram was used in order to observe risk status of the volunteers and to illustrate the interaction of their caries related factors. CRT bacteria (Ivoclar/Vivadent) was used for determination of salivary mutans streptococci and lactobacillus while CRT buffer (Ivoclar/Vivadent) for buffer capacity. After identification of high or low levels of risk status, stimulated saliva of the participations was again collected and stored at -70 °C. A direct enzyme-linked immunosorbent assay (ELISA) method was used to measure IgA, sIgA and IgG levels. All data were statistically analyzed for the correlations.

**Results:** It was not found any correlation between the caries risk status of the participations and their salivary sIgA ($r_s = -0.209, p = 0.052$) and IgA ($r_s = -0.206, p = 0.056$). However, there was negative correlation between risk status and IgG ($r_s = -0.277, p < 0.01$).

**Conclusion:** Within the limitations of this study, it seems that other factors might be responsible from the caries process rather than local and general immunity. However, the relation between dental caries and IgG should be studied further.

**Keywords:** Immunoglobulins, caries, ELISA test

## PD09

### Effect of loupe and head lamp on the visual caries detection using ICDAS

Edi Jasarevic, Isabelle Hug, Klaus Neuhaus, Adrian Lussi

Department of Preventive, Restorative and Pediatric Dentistry, University of Bern, Bern, Switzerland

**Aim:** We determined the effect of an additional head lamp with white light on visual caries detection using ICDAS.

**Materials and Methods:** Nine examiners (4 students with one year and 5 students with two years of clinical experience) evaluated caries lesions in 28 extracted human teeth mounted in a dental phantom head.

Each examiner was asked to make 8 examinations: one using an operation lamp but without any visual aids, one with an additional head lamp with white light (LED), one with dental loupes (2.5x) and one with a combination of head lamp and loupes. Between each examination there was an interval of one week. The International Caries Detection and Assessment System (ICDAS) was used for caries detection. Photographs of each surface of the extracted teeth served as gold standard.

**Results:** At D1-threshold, sensitivity using loupe/lamp was significantly lower than without any visual aids (0.44 compared to 0.55). Specificities and sensitivities on the D3-threshold were not influenced by any method (0.52 to 0.6). There was a trend of higher intraexaminer agreement when optical aids were used (from 0.57 with no visual aids to 0.74 with lamp and loupes).

**Conclusion:** Generally speaking, an additional headlamp with white light does not support caries detection. In addition, combination of white light and loupes may hamper caries detection.

## PD10

### Reproducibility of near-infrared light transillumination for approximal enamel caries: a clinical controlled trial

Fabian Jost¹, Jan Kühnisch², Adrian Lussi¹, Klaus Neuhaus¹

¹Department of Preventive, Restorative and Pediatric Dentistry, University of Bern, Bern, Switzerland, ²Department of Conservative Dentistry and Periodontology, Ludwig-Maximilians-University of Munich, Munich, Germany

**Aim:** To test the reproducibility of a near-infrared (NIR) transillumination device (DIAGNOcam, KaVo) for approximal enamel caries detection.

**Materials & Methods:** Seventy unrestored approximal surfaces in 35 patients with permanent dentition ($age > 14$) were included in this study. Initially, the patients underwent visual examination and bitewing radiographs (BW) were taken, if necessary. After receiving informed consent one interdental space with either an initial lesion and/or no caries was chosen. Both teeth of this selection were photographed with NIR transillumination and an orthodontic separation rubber was placed. The gold standard was visual-tactile caries detection, which was performed upon removing the rubber the next day. The tooth surfaces were examined by two examiners using the universal visual scoring system (UniViSS) with a surgical microscope at 6.4X. Reproducibilities were calculated using weighted kappa ($w_k$) statistics.

**Results:** Out of the 70 surfaces 31 (44%) had no caries. The intra-rater agreement of both diagnostic methods presented good $w_k$. Intra-rater agreement (BW/NIR) was (0.62/0.68) for examiner 1 and (0.79/0.62) for examiner 2, respectively. The inter-rater agreement with the BW ($w_k$ 0.62) showed a good correlation as well, while the $w_k$ value for NIR was only moderate (0.51).

**Conclusion:** Generally speaking, agreement with NIR was worse compared to BW. The reason for this could be the missing calibration of the examiners and shadow artifacts in the margin region of the tooth in some NIR-pictures. They may be attributable to tooth morphology, crown angulation or width of the alveolar bone.
## PD11

**Oral health status of non-phobic/dentally phobic individuals: Secondary analysis of the Adult Health Dental Survey**

Ellie Heidari, Avi Banerjee, Tim Newton

King's College London, London, UK

**Introduction:** Dental anxiety is widespread across the United Kingdom and according to Adult Dental Health Survey (ADHS, 2009), 11% of the adult population have severe dental anxiety. Dentate people with dental anxiety present with poorer oral health and attend dentists irregularly. Dental anxiety is higher among those from the lower social classes and among females.

The aim of this study was to analyse the oral health status of patients with and without dental anxiety through secondary analysis of data from a National survey of the UK population. We will also describe the oral health's determinants and oral health related QOL and Oral Impacts on Daily Performance [OIDP]) in both groups.

**Methods:** Permission to access the data set of the ADHS was sought from UK discovery.

Descriptive statistics comparing individuals with severe levels of dental anxiety (MDAS score > =19) to those with moderate or mild dental anxiety, were calculated using SPSS v11.0

**Results:** There were more women (16.8% [1023]) than men (7% [344]) who reported dental phobia. Generally, people with dental phobia were unskilled workers, single with lower educational attainment. They also were irregular attendees, had less restored dentition, increased scores of Puss, Ulceration, Fistuale, Abscess (PUFA). However, they had the similar numbers of sound and missing teeth as participants without dental phobia. Interestingly, they reported better oral hygiene practises.

**Conclusion:** Patients with dental phobia have greater dental treatment needs. They perceive their oral health as poor which has an implication for their oral health related quality of life.

## PD12

**FoodForTeeth: A novel approach to diet diaries, caries risk and erosion risk**

Prateek Biyani¹, Jasneet Gulati²

¹The University of Sheffield, Sheffield, UK, ²Guy's and St Thomas' NHS Foundation Trust, London, UK

The Dental team plays an important role in educating patients about the impact of diet on oral health. The two major disease processes influenced by our diet are caries and dental erosion.

Advances in mobile technology have seen a modernisation of the way that information is shared and patient education is delivered in healthcare. This includes the use of applications (apps) that can be downloaded on to most mobile devices.

The FoodForTeeth app was designed as an oral health promotion tool with the modern patient in mind. The app has two major objectives:

1. To allow patients to record a diet diary, which they can share with their dentist to receive tailored dietary advice;

2. To allow patients to search a database of common foods and drinks to learn about their caries and erosion risk.

Diet diaries are an underutilised investigation in general dental practice. The app allows patients to easily record a diet diary, and is supplemented with instructions and advice to support the patient. FoodForTeeth aims to promote the use of the diet diary as a special investigation in patients who experience caries or dental erosion.

The app allows patients to search a user-friendly food and drink database, with caries risk and dental erosion risk expressed as traffic light indicators. The role of dietary carbohydrates in the patient experience of caries is just one part of a complex disease process, but the app aims to help patients make informed decisions about their diet and thereby promote oral health.

## PD13

**Design, build and validation of a realistic artificial mouth model for erosion testing.**

Abubaker Qutieshat, Graham Chadwick, Andrew Mason

University of Dundee, Dundee, UK

To facilitate the development of a realistic erosion testing regime, an in vitro artificial mouth model has been designed, built and validated. This work was sought to mimic the interaction of saliva and enamel during the process of consuming an erosive beverage. The model allows researchers to gather data using customizable experimental diets without the technical burden of dealing with a non-realistic regime. The design and build of the artificial mouth model along with its associated equipment and parameters are described. The device is designed on a fully adjustable multitask basis in which the operator can set several variables such as the desirable salivary kinematic behaviour, offensive beverage flow rate and volume of consumption. This, subsequently, allows the samples preloaded on the system to be tested for surface characteristics to determine the extent of erosion if any. The model also allows the resultant solution to be analysed for traces of calcium and phosphate ions. To validate the model, experimental diets were performed repeatedly using specimens prepared from ostrich eggshells, and compared to those obtained from extracted human teeth specimens for the same simulated experimental setup. The associated percentage error for surface ion loss and hardness were equal to or smaller than 0.8% and 1.0% respectively. The high degree of agreement and the consistency of results showed that our model is able to mimic realistic scenarios and is capable of producing reliable, reproducible and accurate outcomes. This capability allows further research to be conducted with focus on dental erosion prevention.

## PD14

**Dental sealants: comparison of different materials in a prospective, controlled, split-mouth clinical trial**

Matteo Basso¹, Manuel Goñe Benites¹, Piyush Khandelwal², Malek Turqui¹

¹University of Milan, Galeazzi Orthopaedic Institute, Dental Clinic, Milan, Italy, ²GC Europe NV, Leuven, Belgium
The purpose of this study is to compare the performance of a flowable composite resin (GradiaFlo, GC Corporation, Japan) with a glassionomer cement (Fuji Triage, GC Corporation, Japan), evaluating their preventive action on dental caries and mechanical strength after placement as fissure sealants. 41 patients aged less than 14 years were selected. They needed sealants on all 4 first molars, for a total of 164 seals. One side of the mouth was randomly assigned to composite group, and the other half to glassionomer group (split-mouth). Follow-ups were scheduled at 2, 4, 6, 12, 18, 24 months. Through magnifying loupes (Zeiss, 3.5x) and intraoral photographs the state of the seals (intact, partially lost, lost) and the presence of dental caries in sealed areas were evaluated. At 24

months, in the composite group, of the initial 82 sealants, 18 were found intact. During the study were detected 15 partially-lost composite sealants, and 15 lost. In the glassionomer group 17 were intact at 24 months, with 27 partially lost and 19 completely lost. It was detected the occurrence of one new caries for each group after 2 years. After statistical analysis, no difference is reported by the number of restorations that were completely lost for the 2 groups (T-test p = 0.23). The glassionomer group has a greater tendency to partial loss (p = 0.008) while the composite group has a greater tendency in preservation of the integrity (p = 0.02). Despite these differences, both materials appear equally effective in preventing tooth decay.