bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of dentine thickness on diffusion of resin monomers in vitro
Authors: HAMID A. , HUME W.R.
Published: August 2010

summary
Forty extracted human third molar teeth were divided into four groups, each of 10 teeth, to test the hypothesis that dentine thickness variation influences diffusion of the monomers 2‐hydroxy‐ethylmethacrylate (HEMA) and triethylene glycol dimethacrylate (TEGDMA) from light‐cured bonding resin‐composite resin restorations to the pulp space. An occlusal cavity 6 mm in diameter was prepared in each tooth of four groups with remaining dentine thickness of 3.4–3.6, 2.4–2.6, 1.4–1.6 and 0.4–0.6 mm, respectively. A polypropylene chamber was attached to the cemento‐enamel junction of each tooth to contain I mL of distilled water. Each cavity was treated with Scotchbond Multipurpose (3m, U.S.A.) then restored with Z100 (3m) and light activated for 30 s. Water samples were retrieved over a time course up to 30 days and analysed by high performance liquid chromatography. Both HEMA and TEGDMA were detected in the pulp samples for all teeth. Decreasing dentine thickness substantially increased pulpward diffusion rate of both HEMA and TEGDMA during the first day after placement, as well as the total release of both components from a bonding resin‐composite combination in vitro.
Fractals in restorative treatment of teeth
Authors: GONZALEZ‐GONZALEZ J.M.
Published: August 2010

summary
Previous studies support the view that the oral medium is a dynamic system composed of several elements, among which are restorations in teeth. The author believes that the evolution in time of a restoration can be non‐lineal and that it has an irregular and chaotic behaviour. To investigate the theory, the author studied, between 1991 and 1994, on their first visit to a dental clinic in Salamanca, the restorations of 583 patients of both sexes. The group results were distributed throughout three age ranges, i.e. 16‐65, 26‐55 and 36‐45. In each group the total number of fillings in situ in each tooth was recorded using the method ‘Expansion‐Contraction Systems’. The results show that the restorative treatment of teeth using fillings follows a non‐lineal dynamic of chaotic behaviour and irregular geometry, which suggests it is a fractal.
Myoelectrical activity of clinical rest position and jaw muscle activity in young adults
Authors: RILO B. , SANTANA U. , MORA M.J. , CADARSO C.M.
Published: August 2010

summary
Electromyographic activity of anterior temporal, superficial masseter, deep masseter and anterior digastric muscles was measured in 40 young healthy men and women during rest (at the beginning and the end of tests), clench, maximal opening, lateral displacement and CR manipulation. During initial rest position myoelectrical activity was 1.9 μV increasing to 2.1 μV at the end of tests (P = 0.08). During clench and maximal opening no significant differences between the sexes were found. The digastric muscle showed considerable activity during maximal opening, lateral displacement and CR manipulation.
Existence of Candida albicans and microorganisms in denture stomatitis patients
Authors: KULAK Y. , ARIKAN A. , KAZAZOGLU E.
Published: August 2010

summary
The aetiology of denture stomatitis is not clear from the literature. Some studies show its aetiology as Candida albicans, while other reports point out the significance of microorganisms. In this study the existence of C. albicans and microorganisms was investigated in subjects with and without denture stomatitis. The results showed that a combination of C. albicans and microorganisms is more likely to be responsible for denture stomatitis.
Relationship between body mass index and the remaining alveolar ridge
Authors: KLEMETTI E. , KRÖGER H. , LASSILA V.
Published: August 2010

summary
Severe residual ridge resorption may occur in individuals with either high or low mineral density in the skeleton. Heavy individuals with a heavy skeleton and a large percentage of fat in the body are less predisposed to osteoporosis than small individuals are. In addition, the jaws of heavy subjects are probably more massive and thick than the jaws of smaller individuals. The purpose of this study was to examine whether, after a long period of edentulousness, the size of the subject is associated with the height of the remaining alveolar ridge and difficulties in wearing complete dentures. The conclusions of this study suggest that the size of an individual may play an important role in the destiny of the residual ridges. Heavy subjects with large jaws have more bone substance to be lost. Wider supportive tissues in the mandible also may provide better possibilities for the use of complete dentures than do the jaws of small individuals.
Stability of the mandibular position in occlusion of mandibulectomy patients with lateral discontinuity defect
Authors: TANIGUCHI H. , ISHIWATA H. , OHYAMA T. , SHINOZUKA O.
Published: August 2010

summary
In mandibulectomy patients with lateral discontinuity defect, the mandible is severely deviated and the occlusion is considered to be unstable. A thorough understanding of the mandibular occlusal position of these patients is important to achieve desirable results in their occlusal rehabilitation. This study compared the stability of the mandibular positions in occlusion, when the opening distance or the biting force was changed during mandibular movements, by simultaneously measuring four points on the mandible three‐dimensionally. This study indicated that the mandibular positions in occlusion of these patients were extremely unstable as compared with those of the normal subjects and were considerably different from each other when the opening distance or the biting force was changed during mandibular movements.
Marginal fit consistency of copy‐milled all‐ceramic crowns during fabrication by light and scanning electron microscopic analysis in vitro
Authors: GROTEN M. , GIRTHOFER S. , PRÖBSTER L.
Published: August 2010

summary
The aim of this study was to evaluate the marginal fit of copy‐milled Celay In‐Ceram® crowns after different fabrication steps and to compare light‐microscopic with scanning‐electron‐microscopic data. A master steel die of an upper middle incisor with a shoulder preparation and a rounded inner line angle was used. Impressions were taken to produce 10 working stone dies. One crown per working die was manufactured. The evaluation of the external marginal gap was performed on the master steel die by using a light microscope and a computerized video image analysis system after copy milling (A), glass infiltration (B), and veneering (C). Approximately 3900 readings were taken. In a final series the veneered crowns were measured by using a scanning electron microscope (Cs), yielding approximately 1000 readings. The results obtained were: A mean, 25.1 μm; s.d., 5.1 μm; range, 2.5–76.8 μm: B mean, 20.6 μm; s.d., 2.3 μm; range, 2.5–76.1 μm: C mean, 18.3 μm; s.d., 4.1 μm; range, 2.5–87.2 μm: Cs mean, 23.0 μm; s.d., 7.6 μm; range, 0.0–94.5 μm. The results were statistically evaluated using the t‐test. The differences found between the series did not show practical relevance. Therefore, it is concluded that the manufacturing steps after copy milling have no obvious influence on the external marginal gap width. Scanning electron microscopic data seem to confirm the light‐microscopic results. Hence, we expect that the Celay In‐Ceram method yields a clinically acceptable marginal fit.
Perceived masticatory function among elderly people
Authors: OW R.K.K. , LOH T. , NEO J. , KHOO J.
Published: August 2010

summary
This Study investigated the status and associations of perceived chewing ability of a group of 891 elderly people, aged 55‐91 years (average age 66 years). The majority of subjects (69%) considered that they could chew well. Only 9% reported poor chewing ability. This judgement was not associated with age. More men (11%) than women (6%) had reported poor chewing ability. Subjects with better perceived general and craniomandibular health reported better chewing ability. However, although related to permanent tooth loss, the perception of chewing ability was not seemingly associated with prosthetic rehabilitation. All elderly subjects with complete dental arches had no complaints of perceived chewing difficulty. Freedom from symptoms of craniomandibular pain when chewing, bilateral chewing activity and a wide choice of food range or textures were associated with favourably perceived chewing ability. This study identifies several suitable criteria for judging masticatory function and suggests that these may be used to complement chewing ability as an alternative measure of masticatory performance. These criteria are applicable to the elderly person, in particular, and warrant adequate clinical application.
Static and dynamic moduli of composite restorative materials
Authors: JACOBSEN P.H. , DARR A.H.
Published: August 2010

summary
A series of polymeric composite restorative materials cured by primary and secondary methods was examined by static and dynamic testing. The static modulus of elasticity, dynamic modulus and glass‐transition temperature were determined over a three‐month period with the intention of characterizing monomer conversion. Heat and pressure curing of one material gave good conversion, but not all combinations of blue‐light irradiation achieved full conversion. The use of a curing oven, whether as the primary or secondary mechanism did not result in a significant improvement in modulus. The use of a dynamic mechanical thermal analyser provided good data and this type of equipment is recommended for the characterization of polymeric materials.
Bonding of silver‐palladium‐copper‐gold alloy with thiol derivative primers and tri‐n‐butylborane initiated luting agents
Authors: MATSUMURA H. , A T. TANAK , ATSUTA M.
Published: August 2010

summary
This in vitro study evaluated the effect of two primers on bond strengths and durability of luting agents joined to a silver‐palladium‐copper‐gold alloy. One primer (Metal Primer) contained methacryloyloxyalkyl thiophosphate derivative (MEPS). The other primer (V‐Primer) contained 6‐(4‐vinylbenzyI‐n‐propyl)aniino‐l,3,5‐triazine‐2,4‐dithiol (VTD). The luting agent was a methyl methacrylate (MMA)‐based adhesive resin that contained 4‐methacryloyloxyethyl trimellitate anhydride (4‐META) and was initiated with tri‐n‐butylborane derivative (TBB). In order to evaluate the function of 4‐META, MMA‐TBB resin without 4‐META was used as a control. The alloy specimens were bonded with six combinations of two primers and two luting agents. Shear bond strengths were determined before and after thermocycling. Both primers significantly elevated the bond strengths of the luting agents joined to the alloy. For unprimed groups, 4‐META resin showed a more durable bond than did MMA‐TBB resin. Combined use of Metal Primer with 4‐META resin reduced the bond strength, while combination of V‐Primer and 4‐META resin did not affect the bond strength.
The influence of anterior guidance and condylar guidance on mandibular protrusive movement
Authors: OGAWA T. , KOYANO K. , SUETSUGU T.
Published: August 2010

summary
This Study reveals the influence of the incisal and condylar guidance on mandibular protrusive movement. The protrusive movements were measured on 54 young adults (27 females, 27 males) using a three‐dimensional mandibular movement analysing system. The inclinations of the sagittal paths on the incisor, canine, 1st molar, 2nd molar and condylar points were calculated, and multiple regression analysis was performed to evaluate the influence of the incisal and condylar paths on the path of each tooth quantitatively. The influence of the incisal path on any tooth path was consistently greater than that of the condylar path. The condylar path had a greater influence on the paths of posterior teeth than on the paths of anterior teeth, especially in the female subjects. The influence of the condylar path on the molar paths was twice as great in the female than that in the male subjects. It was concluded that the influence of the incisal and condylar guidance on the protrusive movement path varies according to the kind of tooth and the gender of the subject. These guiding system characteristics were confirmed by morphological analysis.
Relationship between size of denture foundation area and resorption of alveolar ridge in the edentulous mandible
Authors: SUENAGA K. , SATO T. , NISHIGAWA G. , MINAGI S.
Published: August 2010

summary
The relationship between the size of the denture foundation area and the resorption of the alveolar ridge was investigated in 55 edentulous subjects. The denture foundation area was recorded using a modelling compound impression technique with border moulding. Both sides of each edentulous mandible were examined separately, making a total of 110 experimental sides in the study. On a stone cast made from each impression, the size of the superficial denture foundation area and of the projected denture foundation area on the tentative plane of occlusion of each anatomical zone were measured. The vertical height of the alveolar ridge at the lateral incisor and first molar region was also evaluated. The size of the superficial denture foundation area in the antero‐lingual and postero‐lingual zones showed no significant correlation with the degree of alveolar ridge resorption. The size of the projected denture foundation area on the tentative plane of occlusion in the anterior section showed negative significant correlation with the degree of alveolar ridge resorption. The size of the projected denture foundation area on the tentative plane of occlusion in the posterior section showed no significant correlation with the degree of alveolar ridge resorption.
Titanium for removable dentures. I. Laboratory procedures
Authors: MORI T. , TOGAYA T. , JEAN‐LOUIS M. , YABUGAMI M.
Published: August 2010

summary
To test the hypothesis that titanium (Ti) removable partial dentures (RPDs) would function for a period of at least 2 years without failure, 10 patients were selected to receive dentures made from Ti and Co–Cr. The Ti RPDs were constructed identically to conventional cobalt–chromium (Co–Cr) dentures. Five complete Ti dentures were also included and the laboratory procedures involved for making both complete and partial dentures were evaluated. The detection of internal defects by radiography made the screening of Ti castings possible and led to a rejection of specimens showing porosities of more than 0.5 mm in flexible members. Co–Cr frames on the other hand cannot be screened in this way. The success rate in the casting of Ti was 60% for both partial and complete dentures, but as casting technology has since improved, the rate is expected to be higher, particularly where complete denture palates have optimum thickness. The success rate in the casting of Co–Cr RPDs was 100% without radiographic screening. The weight difference between Ti and Co–Cr RPDs was in the range of 1.3 to 3.9 g at issue and is generally higher as the volume of denture frames increases. A large difference would be of clinical significance in maxillary complete dentures. The low density of Ti allows for the adoption of a useful pre‐clinical quality‐control process using commonly available dental X‐ray units.
Reported symptoms from the masticatory system and general well‐being in rheumatoid arthritis
Authors: KALLENBERG A. , WENNEBERG B. , CARLSSON G. E. , AHLMEN M.
Published: August 2010

summary
Eighty‐one patients with rheumatoid arthritis (RA) and 41 patients with temporomandibular disorders (TMD) were evaluated with questionnaires regarding subjective symptoms from the masticatory system. The general well‐being was assessed using the Mood Adjective Check List (MACL) and the Body Symptom Scale (BSS). Patients with rheumatoid arthritis in general had less symptoms from the masticatory system than TMD patients. The RA patients reported that their symptoms were related to acute phases of the general disease, while the TMD patients reported that mental stress, anxiety, bruxism and chewing aggravated their symptoms. The RA patients had more general physical discomfort than TMD patients according to the BSS. The RA patients rated their mental well‐being (MACL) close to normal, except that they were less active than TMD patients. The TMD patients, on the other hand, showed higher values for mental tension. In conclusion, many patients with RA will develop TMD symptoms but there is a great variation in time relationship between the onset of RA and involvement of the masticatory system.
A three‐dimensional non‐invasive study of head flexion and extension in young non‐patient subjects
Authors: FERRARIO V. F. , SFORZA C. , POGGIO C. E. , SCHMITZ J. H. , TARTAGLIA G.
Published: August 2010

summary
Head flexion and extension movements near the natural head position (NHP) were analysed for the location of the mean instantaneous centre of rotation (ICR). Forty‐six healthy young adults (30 women and 16 men) with sound dentitions, free from cranio‐cervical disorders, performed habitual movements that were automatically detected and measured by an infrared three‐dimensional motion analyser. ICR and curvature radius were calculated for each movement and subject. In both extension and flexion, ICR position changed during the motion. The movement was symmetrical in all subjects. No gender or flexion/extension differences were found for both ICR position and relevant curvature radius. On average, ICR relative to NHP soft‐tissue nasion was located at about 150% of the soft‐tissue nasion–right tragus distance, with an angle of about 220° relative to the true horizontal. Results suggest that head flexion or extension is always performed with a combination of rotation (atlanto‐occipital joint) and translation (cervical spine) even in the first degrees of motion. Moreover, NHP at rest seems to be some degree more flexed and anterior than head position during movements. These relative positions and their muscular determinants could also influence mandibular posture at rest and during functional movements.
Fibre type grouping in porcine masseter and soleus muscles assessed by the enclosed fibre type concept. A statistical and computational analysis
Authors: STRÖM D. , HOLM S.
Published: August 2010

summary
Muscle function is determined not only by the frequency of slow (type I) and fast (type II) fibres but also the spatial fibre type organization. During ageing as well as in muscle disorders, divergencies from the normal pattern may occur and are expressed as ‘fibre‐type grouping’. To elucidate whether intramuscular differences in spatial fibre type arrangements may underlie the functional heterogeneity of the porcine masseter, the arrangements of intrafascicular type I and type II fibres were assessed in terms of the number of enclosed fibres in whole fascicles. The intrafascicular proportions of edge‐and centrally located type I and type II fibres were investigated. Two hundred and forty‐two porcine masseter fascicles (six masseters) and 63 pig soleus fascicles (five soleus muscles) were investigated by ATP‐ase histochemistry. All fascicles were from 11 domestic pigs (1 year, 70–90 kg body weight, all female). Sixty‐nine to 90% of the total fibres were type II fibres in the porcine masseter (P < 0.01). In four of five soleus muscles the type II fibre population was dominant. No enclosed type I fibres could be identified in the porcine masseter muscles. This was in contrast to the finding of 1270 enclosed type II fibres. Five enclosed type I fibres (two soleus) and 361 enclosed type II fibres were identified in the pig soleus. The spatial analysis indicated that the fibre type arrangements in the porcine masseter muscles were not homogeneous. No biopsies with random type II fibre organization were identified. Furthermore, half the number of biopsies showed type I fibre segregation. These data suggest that the porcine masseter cannot be considered as having one homogeneous structural identity.
Titanium for removable dentures. II. Two‐year clinical observations
Authors: THOMAS C. J. , LECHNER S. , MORI T.
Published: August 2010

summary
Titanium (Ti) is a relatively new metal in prosthodontics. As a possible material for removable partial dentures (RPDs), it was used in its pure form to make 10 RPDs which were compared with 10 identical cobalt‐chromium (Co–Cr) alloy RPDs in a clinical trial. The dentures were used alternately for four weeks, the subjects were asked to answer a questionnaire and then the Co–Cr dentures were withdrawn. The Ti dentures were then followed up for 2 years and another standardized questionnaire administered. A survival rate of rests and retainers of 91% was recorded and the dentures were found to be more comfortable (55%) and preferred (64%) than the Co–Cr dentures. Factors to increase the success rates are discussed.
Functional unilateral posterior crossbite. Orthodontic and functional aspects
Authors: DE BOER M. , STEENKS M.H.
Published: August 2010

summary
The purpose of the study was to evaluate the effect of early orthodontic treatment of functional unilateral posterior crossbite (FUPC) and to evaluate temporomandibular function in the short and long term. Orthodontic treatment consisted of slow expansion of the maxillary dental arch by means of a removable expansion plate, with flat coverage of the occlusal surfaces of the left and right posterior teeth. Evaluation of the occlusion showed a strong correlation between the crossbite side and the direction of the RCP‐ICP slide and with the side of first occlusal contact in RCP. In 26 of 27 children that were treated (one withdrew), the average time required for correction of the crossbite was 7 months, followed by a retention period, on average, for 6 months after completion of treatment. Early orthodontic treatment resulted in an elimination of occlusal disturbances, and the crossbite remained stable on follow‐up during an average of 8 years after the retention period, except in two children with a class III tendency. In nine other children an orthodontic anomaly had developed requiring further treatment (two children showed crowding and seven children showed a class II malocclusion). This study showed that FUPC can be treated adequately by early orthodontic intervention; however, its correction does not guarantee the absence of functional disturbances at a later age. Therefore, FUPC should be treated early in order to achieve normal growth and development rather than to prevent temporomandibular disorders.
In vitro evaluation of a glass–ceramic restorative material
Authors: PRÖBSTER L. , GEIS‐GERSTORFER J. , KIRCHNER E. , KANJANTRA P.
Published: August 2010

summary
The aim of the present study was to compressive and diametral tensile strength, evaluate the clinically relevant properties of the compressive strength and marginal fit of full crowns. recently introduced ceramic material IPS Empress™, The results show that this material is a highly which is marketed for all‐ceramic restorations. The developed glass‐ceramic with physical properties following parameters were investigated: three‐ and making this dental material well suitable for four‐point bending strength, bi‐axial flexure strength, adhesively luted restorations.
The effect of posterior tooth guidance on non‐working side arbitrary condylar point movement
Authors: SARINNAPHAKORN L. , MURRAY G. M. , JOHNSON C. W. L. , KLINEBERG I. J.
Published: August 2010

summary
Occlusal form is frequently modified in clinical practice and yet we do not have detailed knowledge of the possible effects of these changes on condylar movement. The aim of this study was to quantify the effects of an alteration in the occlusion on condylar movement during a lateral excursive jaw movement. Posterior tooth guidances (i.e. metal overlays) were attached to both maxillary first molars. The movement of arbitrary condylar points on the non‐working side was recorded in seven subjects during lateral excursion under natural tooth guidance (control) and was compared with that after placement of the overlays (guidance). The guidance resulted in statistically significant changes to the displacement of the arbitrary condylar points on the non‐working side. For example, at a standardized (3 mm) displacement along the mid‐incisor point trajectory during the lateral excursion for both control and guidance in all subjects, the corresponding displacements of the condylar points were statistically significantly decreased under the guidance situation in comparison with the control situation. These data suggest that, for the same magnitude of mandibular displacement during lateral excursion, the introduction of a posterior tooth guidance limits condylar displacement on the non‐working side.
Posterior bridges retained by resin‐bonded cast metal inlay retainers: a report of 60 cases followed for 6 years
Authors: ÇÖTERT H. SERDAR , ÖZTÜRK B.
Published: August 2010

summaryBetween May 1989 and July 1994, 60 adhesive fixed partial posterior dentures retained by resin‐bonded cast metal inlays were placed under controlled conditions. The influence of various prognostic factors on the event free and overall service duration was investigated with univariate and multivariate analysis. The majority of the failures (16 of 18) were caused by loss of adhesion at the metal cement interface and were observed either as debonding of the restorations completely or dislodgement of a single retainer. The other two failures appeared as secondary caries. Univariate analysis demonstrated that, retainer type, approximal configuration and dentine exposition had no effect on the event free service duration. On the other hand, gingival finishing level and luting agent were found to have an effect. Univariate testing was also conducted for the overall service duration and none of the variables were found to have an effect, Multivariate Cox Regression Analysis was performed to estimate the influence of categorical covariates: type of retainer, approximal preparation modification, gingival finishing level, preparation depth and luting agent on survival rates of event free and overall service duration. Luting agent was found to be the single independent prognostic variate (P< 0·0001) for the event free service duration and the other covariates were rejected. For overall service duration, none of the variables were found to be effective.
Autoradiographic determination of marginal leakage of a pressed glass ceramic inlay
Authors: CANAY R. Ş. , HERSEK N. E. , UZUN G. , ERCAN M. T.
Published: August 2010

summary
The marginal integrity and microleakage of pressed glass ceramic inlays were evaluated using autoradiography. IPS/Empress ceramic inlays were fabricated for 10 human molar mandibular teeth. After adjusting the inlays, they were etched with 37% phosphoric acid gel for 30 s and silanized with Monobond S for 30 s. Before cementation with dual cure resin cement the inlays and cavity walls were gently covered with a thin layer of bonding agent. When the cementation process was completed the samples were cycled 300 times between a 55°C hot bath and a 5°C cold bath. The samples were placed in each bath for 60s, with 5 s intervals between immersions, then the specimens were immersed in an aqueous solution of Ca‐45. After 24 h the inlay and tooth assemblies were removed, rinsed with water and placed in cold‐cured acrylic resin, then sectioned through the long axis for autoradiographic analysis. According to the penetration of Ca‐45, the microleakage level was scored for each section. The results indicated slight penetration of Ca‐45 on autoradiographic films.
Biomechanical effects of double or wide implants for single molar replacement in the posterior mandibular region
Authors: Sato Y. , Shindoi N. , Hosokawa R. , Tsuga K. , Akagawa Y.
Published: August 2010

Double implants have been thought to have biomechanical advantages for single molar replacement. To evaluate the effectiveness of double implants versus a wide implant, the vertical forces and torque on each implant were calculated by three‐dimensional geometric analysis. Buccal load (100 N) perpendicular to cuspal inclination (20°) was applied at the occlusal surface of the superstructure. The three kinds of load points (A, B, C) were 1·5, 3·5, and 5·5 mm from the mesial contact point, respectively. Three implants were compared: mesial and distal double implants (∅ 3·3 mm), and a wide implant (∅ 5 mm). The wide implant showed torque around the long axis (1·8–15·0 N · cm) whereas double implants had no torque. On the other hand, the vertical forces on the mesial double implant were both smaller (60%: loaded at point C) and larger (140%: loaded at point A) than the wide implant. Given the smaller surface area of the mesial double implant, this large force may generate much higher stress in the peri‐implant bone. These results suggest that the biomechanical advantage of double implants for single molar replacement is questionable when the occlusal force is loaded at the occlusal surface near the contact point.
An appraisal of the literature on centric relation. Part I
Authors: Keshvad A. , Winstanley R. B.
Published: August 2010

The literature directly and indirectly related to centric relation (CR) has been reviewed chronologically. More than 300 papers and quoted sections of books have been divided into three sections. The first two parts are related to CR. Studies in this group mainly compared either the position of the mandibular condyle or the mandible itself in different CR recordings. Various tools were discussed for this purpose. The third part of the paper is about CR–centric occlusion (CO) discrepancy. CR still remains one of the controversial issues in prosthodontics and orthodontics. Debates such as mounting casts on the articulator by reproducible records for orthodontic treatment planning and end results, and whether or not orthodontic treatment based on CO causes temporomandibular joint dysfunction, remain unsolved. The references are listed at the end of Part III.
Physical properties of resinous cements: an in vitro study
Authors: Fraga R. C. , Luca‐Fraga L. R. L. , Pimenta L. A. F.
Published: August 2010

The flow rate capacity, hydrolytic degradation and radiopacity of three resin‐based cements were tested and compared with zinc phosphate cement, when used in accordance with the manufacturer's instructions. There are no significant differences among the cements with regard to the flow rate. The zinc phosphate cement showed superior hydrolytic degradation compared with the other cements tested. The cements presented different radiopacities and the zinc phosphate cement was the most radiopaque. The results suggest that the development of resin‐based materials associated with adhesive procedures can increase the effectiveness of indirect restorations.
Different responses of masticatory movements after alteration of occlusal guidance related to individual movement pattern
Authors: Ogawa T. , Ogawa M. , Koyano K.
Published: August 2010

We hypothesized that the motor response of the masticatory system to peripheral inputs varies according to the functional potential of an individual. The specific aim of the present study was to determine whether individually different types of masticatory patterns, especially with respect to the closing movement pattern, would produce different motor responses to an alteration of occlusal guidance. The inclination of the occlusal guidance was steepened by approximately 10 degrees by attaching a metal overlay to the lingual surface of the maxillary working‐side canine. The masticatory movements of 20 young adults were measured using a three‐dimensional mandibular movement analysis system before and after the alteration of occlusal guidance. The individual masticatory patterns were divided into two groups based on the closing movement pattern before the alteration of occlusal guidance, i.e. vertical and lateral types. The alteration of occlusal guidance significantly influenced the masticatory closing angle, closing time, occlusal time, the stability of the opening angle and the cycle time in the lateral‐type group (n = 9, paired t‐test; P < 0˙05), while no significant changes were found in the vertical‐type group (n = 11). These differences in motor response between the two groups were not found in the overall analysis of all the 20 subjects. We concluded that the oral motor response to the alteration of occlusal guidance depends on the individual masticatory movement pattern. Because the present analysis of subgroups of the subjects revealed motor response findings different from those in the overall analysis of all the 20 subjects, such potential subgroupings should be considered as an attempt to identify a specific effect of peripheral inputs on masticatory function in humans.
Spaciostructural analyses of mandibular and perioral soft tissue movements during mastication
Authors: Sakaguchi K. , Kawasaki T. , Nakagawa T. , Araki O. , Kanayama T. , Kawashima T.
Published: August 2010

We considered that elucidation of the movements of perioral soft tissues during mastication would be useful in evaluating masticatory movements. However, evaluation of movements specific to soft tissues is difficult because movements of the surface of the lower face during mastication include movements of the muscles of facial expression and mandibular movements. The aims of this study were to elucidate the influence of mandibular movements on perioral soft tissue movements during mastication using principal component analysis (PCA) and to abstract the component of movement specific to soft tissues in order to evaluate masticatory movements from the movements of perioral soft tissues. The subjects were 10 healthy persons with complete natural dentition. The experimental food used in this study was sufficiently softened chewing gum. The results of this study showed that the movements of mandibular and perioral soft tissue were closely related in the first and third PCs; in other words, the second PC was the component of movement specific to soft tissues. Thus, elucidation of the second PC is useful for evaluation of masticatory movements from movements of perioral soft tissues.
Influences of occlusal and skeletal discrepancies on biomechanical environment in the TMJ during maximum clenching: an analytic approach with the finite element method
Authors: Tanaka E. , Tanaka M. , Watanabe M. , Del Pozo R. , Tanne K.
Published: August 2010

The purpose of this study was to investigate the influences of occlusal and skeletal discrepancies on temporomandibular joint (TMJ) stresses during maximum clenching. A three‐dimensional (3‐D) finite element model of the mandible including the TMJ was developed as a standard model. Furthermore, nine modified models were established; one dentoalveolar open bite model and eight skeletal open bite models with varying gonial angles or mandibular plane angles (FMAs). For the dentoalveolar open bite model, the TMJ stresses were larger than those for the standard model, although the distribution pattern was not essentially varied. In the skeletal open bite model with greater gonial angle or FMA, the TMJ stresses were significantly larger than those in the dentoalveolar open bite model. In conclusion, the TMJ stress was affected by occlusal and/or skeletal discrepancies, if coexisted in particular, indicating the association with degenerative changes of the TMJ components.
Facial asymmetry in patients with cervicobrachial pain and headache
Authors: Nakamura T. , Okamoto K. , Maruyama T.
Published: August 2010

An increasing number of patients are visiting our hospital who have a chief complaint of neck and shoulder pain and/or headache but who do not have temporomandibular disorders (TMD). We carried out this study with a view to comparing the asymmetry of the facial skeleton or expression of such patients with those of healthy subjects. The incidence of such symptoms of patients and healthy subjects was examined by means of questionnaires. Asymmetry of the facial skeleton of patients was investigated by means of posterioanterior (PA) cephalograms. Facial asymmetry was analysed using the frontal view photographs of faces. We found that the patients had a higher incidence of various symptoms, including fatigability and irritability, in addition to neck and shoulder pain and headache, than the healthy subjects did. Both the healthy subjects and the patients had mandibular skeletal asymmetry to some degree, however, there was no significant difference between the two groups. On the other hand, the patients had a greater level of asymmetry of facial expression, chiefly of the lower face, than the healthy subjects did.
In vitro cytotoxicity of six dentin bonding agents
Authors: Koliniotou‐Koubia E. , Dionysopoulos P. , Koulaouzidou E. A. , Kortsaris A. H. , Papadogiannis Y.
Published: August 2010

The cytotoxicity of six dentin bonding agents (Syntac, Solobond, Bond 1, Scotchbond 1, Heliobond and F‐2000) was tested against an established cell line, L929. Under aseptic conditions 3, 5 and 10 μL dentin bonding agents were placed in the centre of Petri dishes. Each dish was covered with a 5‐mL suspension of fibroblasts at a concentration of 40 000 cells mL–1. The cultures were incubated at 37 °C and cytotoxicity was assessed by a quantitative technique at 24 and 72 h. All the dentin bonding agents were found to be cytotoxic. Scotchbond 1 and F‐2000 showed the highest cytotoxicity followed by Solobond and Bond 1. Heliobond and Syntac were the least toxic materials.
The effect of the addition of surface treated chopped and continuous poly (methyl methacrylate) fibres on some properties of acrylic resin
Authors: Jagger D. , Harrison A. , Vowles R. , Jagger R.
Published: August 2010

Poly (methyl methacrylate), the material most commonly used in the construction of dentures, is not without limitations particularly in terms of mechanical strength, such as flexural and fatigue strength. The Dental Practice Board for England statistics show that many dentures fail as a result of fracture. This study investigated the self‐reinforcement of acrylic resin through the addition of surface treated poly (methyl methacrylate) fibres in chopped and continuous form. The effect of the addition of fibres on transverse and impact strengths was investigated. The addition of surface treated chopped or continuous fibres to acrylic resin did not improve the transverse or impact strengths. The addition of surface treated poly (methyl methacrylate), in the present form, to acrylic resin cannot be recommended as a method of reinforcement.
The effects of oxalate‐containing products on the exposed dentine surface: an SEM investigation
Authors: Gillam D. G. , Mordan N. J. , Sinodinou A. D. , Tang J. Y. , Knowles J. C. , Gibson I. R.
Published: August 2010

In‐office products containing oxalates have been claimed to be clinically effective in reducing dentine sensitivity, although there has been limited supporting clinical data. The rationale for their use appears to be based on their potential to act as occluding and/or nerve desensitizing agents. Four commercially available oxalate‐containing products were applied to etched dentine discs and the extent of tubule occlusion was observed by scanning electron microscopy. Tenure Quick (aluminium oxalate), Sensodyne Sealant (ferric oxalate) and MS Coat (oxalic acid) covered the dentine surface and occluded the tubules. However, Butler Protect (potassium oxalate) did not cover the surface to any great extent but provided some occlusion. The presence of oxalates after application to glass slides and dentine discs was examined using thin film X‐ray diffraction. From samples on glass, only potassium oxalate could be clearly identified (JCPDS 14‐0845). No oxalate was detected on dentine discs in either thin film geometry or standard theta two theta mode. We have demonstrated that professionally applied in‐office products containing oxalate are capable of covering the dentine surface and/or occluding the tubules to varying degrees. However, X‐ray diffraction analysis was unable to confirm the oxalate profile for all products as described in the available commercial literature.
Periodontal findings in patients 10 years after insertion of removable partial dentures
Authors: Kern M. , Wagner B.
Published: August 2010

The purpose of this retrospective study was to evaluate the changes in the periodontal conditions of patients wearing different designs of removable partial dentures over long‐term. Seventy‐four patients treated with 101 mainly conical crown‐retained dentures (CCRDs) or clasp‐retained removable partial dentures (RPDs) or a combination of conical crown and clasp‐retained dentures (CRPDs) were re‐examined 10 years after insertion. Periodontal findings were compared with baseline values at insertion. A deterioration of the probing depths (PDs) and tooth mobility was found. The abutment teeth of the RPDs suffered more severe deterioration than the abutment teeth of the CCRDs and the CRPDs. The absence of a regular recall system for the patients may be responsible for this outcome.
Patient evaluation of treatment with fixed implant‐ supported partial dentures
Authors: Yi S.‐W. , Carlsson G. E. , Ericsson I. , Kim C.‐K.
Published: August 2010

The aim of this study was to analyse the patient evaluation of functional treatment outcome in 40 periodontally compromised patients who received implant‐supported prostheses (ISPs) as part of the total treatment. The treatment protocol comprised periodontal treatment, extraction of teeth with poor prognosis, placement of dental titanium implants, and after healing, insertion of fixed ISPs. Five of the patients became edentulous in one jaw after extraction of all teeth and received a complete ISP, whereas 35 patients became partially edentulous after extraction of some teeth, 12 receiving a partial ISP on ≥ 3 implants, and 23 one on two implants. The follow‐up period was on average 1˙8 years after the connection of the prostheses, which provided the patients a dentition with a mean of 12 occluding dental units. The first author (S.‐W. Yi) performed all implant treatment. Patients’ opinions on oral functions – mastication, phonetics, oral hygiene, chewing comfort and aesthetics – were evaluated by means of a questionnaire both before implant installation and at the last follow‐up. A control group of 30 subjects with a healthy dentition of 14 occluding natural pairs of teeth answered the same questionnaire on one occasion. A great majority of the patients were extremely satisfied with the oral function after treatment and experienced the ISPs as ‘natural teeth’. There was no significant difference between the three treatment groups and the control group for mastication, phonetics, chewing comfort and aesthetics. Patients with ISPs reported a small but significantly greater difficulty with oral hygiene procedures than the controls with natural teeth. Most patients said that they would undergo the treatment again, if necessary, and recommend it to others. It was concluded that the rehabilitation of the periodontally compromised patients, including ISPs on osseointegrated dental titanium implants, resulted in subjectively improved and satisfactory oral function.
Dimensional stability and dehydration of a thermoplastic polycarbonate‐based and two PMMA‐based denture resins
Authors: Pronych G. J. , Sutow E. J. , Sykora O.
Published: August 2010

summary  This study compared the dimensional stability and dehydration of a thermoplastic polycarbonate denture base resin with two conventional polymethyl methacrylate denture base resins. Maxillary complete dentures were fabricated from the three denture materials and the accuracy of fit along the posterior palatal border of the cast used in processing was measured. Measurements were conducted at five palatal locations immediately after processing and at 7 and 30 days during immersion in water (23 °C) and at 7 and 30 days during dehydration (23 °C, 65–75% relative humidity). Percentage mass loss during dehydration was determined with an electronic balance. The thermoplastic material was separately compared with each of the conventional resins using a modified Welch two‐sample t‐test, with a Bonferroni correction for P values. For mean palatal dimensional change, the thermoplastic resin was generally not statistically different from the conventional resins after processing and during immersion (P ≥ 0·06), but was generally less than the conventional resins during dehydration (P ≤ 0·02). For mean percentage mass loss, the thermoplastic resin consistently showed much smaller, statistically significant values compared with the conventional resins (P < 0·001). It was concluded that the thermoplastic resin should show dimensional changes in service comparable with the conventional resins, but less dimensional change caused by dehydration.
Bending strength and depth of cure of light‐cured composite resins irradiated using filters that simulate enamel
Authors: Arikawa H. , Kanie T. , Fujii K. , Shinohara N.
Published: August 2010

summary  This study evaluates the light‐attenuating effects of enamel on the properties of light‐cured restorative resins using simple experimental filters. Three filters were designed to replicate the light transmittance characteristics of 0·5, 1·0 and 1·5 mm thick human enamel. The bending strength, depth of cure, and levels of residual monomer for 12 shades of three commercial light‐cured composite resins were examined. These resins were cured either using direct irradiation from a light source or irradiation through one of the filters. For all materials, the bending strength and depth of cure of specimens irradiated through a filter were lower and the levels of residual monomer were higher than those found in specimens irradiated directly. The results indicate that the light‐attenuating effect of enamel reduces the polymerization efficiency, resulting in poorer mechanical properties of light‐cured composite resins.
Vaccination of mice with chitosan nanogel‐associated recombinant NcPDI against challenge infection withNeospora caninumtachyzoites
Authors: DEBACHE K. , KROPF C. , SCHÜTZ C. A. , HARWOOD L. J. , KÄUPER P. , MONNEY T. , ROSSI N. , LAUE C. , McCULLOUGH K. C. , HEMPHILL A.
Published: August 2010

The effects of nanogel encapsulation of recombinant NcPDI (recNcPDI) following vaccination of mice by intranasal or intraperitoneal routes and challenge infection withNeospora caninumtachyzoites were investigated. Nanogels were chitosan based, with an alginate or alginate‐mannose surface. None of the mice receiving recNcPDI intraperitoneal (i.p.) (without nanogels) survived, whereas intranasal (i.n.) application protected 9 of 10 mice from disease. Association of recNcPDI with nanogels improved survival of i.p. vaccinated mice, but nanogels without recNcPDI gave similar protection levels. When nanogels were inoculated via the i.n. route, 80% of the mice were protected. Association of recNcPDI with the alginate‐coated nanogels protected all mice against disease. Quantification of the cerebral parasite burden showed a significant reduction of parasite numbers in most experimental groups vaccinated i.n., except those vaccinated with alginate‐mannose nanogels with or without recNcPDI. For i.p. vaccinated groups, no significant differences in cerebral infection densities were measured, but there was a reduction in the groups vaccinated with recNcPDI associated with both types of nanogels. Analysis of the immune responses of infected mice indicated that association of recNcPDI with nanogels altered the patterns of cytokine mRNA expression profiles, but had no major impact on the antibody subtype responses. Nevertheless, this did not necessarily relate to the protection.