bluuebunny/crossref_metadata_2025 huggingface dataset:
Temporal and local appearance of alkaline phosphatase activity in early stages of guided bone regeneration
Authors: Stucki U. , Schmid J. , Hämmerle C. F. , Lang N. P.
Published: March 2003

Abstract: Alkaline phosphatase (ALP) catalyzes the hydrolysis of phosphate esters and it seems to be a prerequisite for normal skeletal mineralization. Also, ALP is the most widely recognized marker of osteoblast phenotypes. By a tissue regenerative technique called Guided Bone Regeneration (GBR), it is possible nowadays to regenerate small bony defects. The aim of the present study was to investigate early events in bone healing and neogenesis by studying histochemically the temporal and local appearance of the marker Alkaline Phosphatase (ALP) in a GBR model system. Nine healthy volunteers (5 males, 4 females, mean age 31.7 years) participated in the experiment. After raising a mucoperiosteal flap from the mandibular second molar to the retromolar area in each volunteer, a hollow titanium test cylinder was placed into a congruent bony bed and the coronal end of the cylinder was closed with an ePTFE‐membrane. Then the flap was adapted and sutured to obtain primary wound closure. After 2, 7 and 12 weeks, the regenerated tissue within the cylinders was harvested. Histologically, ALP activity was observed associated with the osteoid seams in the very basal part of the regenerate where new bone trabeculae were in the process of being formed. More coronally, large round cells seemed to secrete an ALP‐positive substance since in the center of such cell clusters strong ALP activity located extracellularly was detected. In the present experiment, ALP seemed to have been an early sign of osteoblast secretion of a matrix which subsequently was determined to become osteoid. ALP activity was never seen isolated within connective tissue and away from bone. This is an indication that its source is linked to existing bone. The present study has documented for the first time the appearance of ALP activity in guided bone regenerations in humans. It has revealed that: 1) Osteogenesis in guided bone regeneration is preceded by localized, marked expression of ALP in an organized connective tissue environment. 2) Bone neogenesis is an early event in this experimental setup and may be detected already 2 weeks after wounding. 3) Expression of ALP and subsequent bone neogenesis is originating from and topographically linked to pre‐existing bone structures.
Maxillary bone grafting for insertion of endosseous implants: results after 12–124 months
Authors: Raghoebar Gerry M. , Timmenga Nicolaas M. , Reintsema Harry , Stegenga Boudewijn , Vissink Arjan
Published: March 2003

Abstract: Insertion of endosseous implants in the atrophic maxilla is often complicated because of lack of supporting bone. Augmentation of the floor of the maxillary sinus with autogenous bone graft has been proven to be a reliable treatment modality, at least in the short term. The long‐term clinical and radiographic outcome with regard to the grafts, the implants and satisfaction of the patients with their implant‐supported overdenture was studied in 99 patients. The sinus floor was augmented with bone grafts derived from the iliac crest (83 subjects, 162 sinuses, 353 implants), the mandibular symphysis (14, 18, 37), or the maxillary tuberosity (2, 2, 2). Before implant installation, the width and height of the alveolar crest were increased in a first stage procedure in 74 patients, while in the other 25 patients augmentation and implant installation could be performed simultaneously (width and height of the alveolar crest >5 mm). Perforation of the sinus membrane occurred in 47 cases, which did not predispose to the development of sinusitis. Loss of bone particles and sequestration were observed in one (diabetic) patient only, in whom a dehiscence of the oral mucosa occurred. A second augmentation procedure was successful in this patient. Symptoms of transient sinusitis were observed in 3 patients. These symptoms were successfully treated with decongestants and antibiotics. 2 other patients developed a purulent sinusitis which resolved after a nasal antrostomy. In all cases, the bone volume was sufficient for implant insertion. 32 of 392 inserted Brånemark implants (8.2%) were lost during the follow‐up. After the healing period of the bone grafts, no sinus pathology was observed. The patients received implant‐supported overdentures (72 patients) or fixed bridges (27 patients). Overall, the patients were very satisfied with the prosthetic construction. We conclude that bone grafting of the floor of the maxillary sinus floor with autogenous bone for the insertion of implants is a reliable treatment modality with good long‐term results.
Treatment of peri‐implantitis by local delivery of tetracycline
Authors: Mombelli Andrea , Feloutzis Andreas , Brägger Urs , Lang Niklaus P.
Published: March 2003

Abstract: The purpose of this study was to investigate the clinical, microbiological and radiological effects of peri‐implantitis therapy by local delivery of tetracycline. In 25 partially edentulous patients, 30 implants with radiographic evidence of circumferential bone loss, and peri‐implant probing depths ≥5 mm were treated with polymeric tetracycline HCl‐containing fibers. Clinical and microbial parameters were recorded at baseline, and 1, 3, 6, and 12 months (M) after treatment. Standardized radiographs were obtained at baseline, M3, and one year after treatment. Two patients were discontinued from the study after 180 days because of persisting active peri‐implantitis with pus formation. The remaining subjects showed a significant decrease of mean peri‐implant probing depth from 6.0 to 4.1 mm (M1, P<0.001), which was maintained over 12 months. In comparison to baseline, the bleeding tendency was significantly reduced after one month, and thereafter (P<0.001). No significant recession of the mucosal margin was noted. The radiologically determined distance from the shoulder of the implant to the bottom of the bony defect decreased slightly, but not significantly, from 5.2 to 4.9 mm. At M1, M3 and M6, mean total anaerobic cultivable bacterial counts were significantly lower than at baseline (P<0.001). A significant decrease in frequency of detection was noted for Prevotella intermedia/nigrescens, Fusobacterium sp., Bacteroides forsythus, and Campylobacter rectus (P<0.01). Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Eikenella corrodens had very low baseline frequencies that could not be significantly suppressed further.

In conclusion, therapy of peri‐implantitis by local delivery of tetracycline had a positive effect on clinical and microbiological parameters.
Role of chitin beads in the formation of jaw bone by guided tissue regeneration
Authors: Kostopoulos Lambros , Lioubavian Natalia , Karring Thorkild , Uraguchi Ryoji
Published: March 2003

Abstract: It has been reported that local application of bone grafts or synthetic bone substitutes (filler materials) may favour bone formation when used in combination with guided tissue regeneration (GTR). Therefore, the aim of the present investigation was to evaluate the effect of application of chitin beads (a bioabsorbable natural polymer) as a bone substitute in bone formation by GTR. The experiment was carried out in 25 rats. The mandibular ramus was exposed on one side after elevation of a muscle‐periosteal flap, and a teflon capsule filled with chitin beads (2.0 mm in diameter) was placed with its opening facing the lateral aspect of the ramus. On the contralateral side of the jaw, serving as control, an empty teflon capsule was placed in the same manner. Groups of 5 animals were sacrificed at 7, 15, 30, 60 and 120 days following capsule placement. Histological analysis demonstrated that the amount of newly formed bone was similar in both experimental and control specimens, amounting to approximately 3% of the central/largest, cross‐sectional area created by the capsule at 15 days, and to approximately 9% of this area at 30 days following capsule placement. At 60 and 120 days, however, the amount of newly formed bone observed in the control specimens was twice as large as that observed in the test specimens, amounting to approximately 31% of the cross‐sectional area created by the capsule at 60 days, and to approximately 45% at 120 days. It is concluded that, although chitin beads (2.0 mm in diameter) are biocompatible, their presence retards bone formation in the model system used.
Sinus lifting procedure
Authors: Kahnberg Karl‐Erik , Nilsson Peter , Hirsch Jan‐Michaél , Ekestubbe Annika , Gröndahl Kerstin
Published: March 2003

Abstract: A prospective study of one‐stage surgery with intrasinus bone transplant and implants has been performed in 26 patients (13 males and 13 females). The aim of the study was to evaluate the success rate with the one‐stage sinus lifting procedure in patients with a need for bony augmentation of the alveolar process. Fifteen patients were partially dentate and 11 edentulous. The mean height of the alveolar ridge was 2.5 mm preoperatively (range 1–5.5 mm). 126 fixtures were inserted, 93 in grafted bone and 33 in alveolar bone. Twenty‐two patients have been followed for three years, 21 for four years and 11 for five years. The clinical overall survival rate was 69.6% although only 61.2% in grafted bone. Ten of the patients had varying degree of sinusitis post‐fixture installation. At the end of the study, 23 patients had permanent bridges. The survival rate was low for inlay supported implants when the one‐stage surgical technique was applied. Two‐stage surgery may be a safer method.
Determining optimal surface roughness of TiO2 blasted titanium implant material for attachment, proliferation and differentiation of cells derived from human mandibular alveolar bone
Authors: Mustafa Kamal , Wroblewski Joanna , Lopez Blanca Silva , Wennerberg Ann , Hultenby Kjell , Arvidson Kristina
Published: March 2003

Abstract: In the complex process of bone formation at the implant‐tissue interface, implant surface roughness is an important factor modulating osteoblastic function. In this study, primary cultures of osteoblast‐like cells, derived from human mandibular bone, were used. The aim was to examine the effect of varying surface roughness of titanium implant material on cellular attachment, proliferation and differentiation. A recognized method of increasing surface roughness and enlarging the surface area of titanium implants is by blasting with titanium dioxide particles: the four specimen types in the study comprised surfaces which were machine‐turned only, or blasted after turning, with 63–90 μm, 106–180 μm, or 180–300 μm TiO2 particles, respectively. The specimens were analyzed by scanning electron microscopy and confocal laser scanning. The turned samples had the smoothest surfaces: average height deviation (Sa) of 0.20 μm. The roughest were those blasted with 180–300 μm particles, Sa value 1.38 μm. Blasting with intermediate particle sizes yielded Sa values of 0.72 μm and 1.30 μm, respectively. Cell profile areas were measured using a semiautomatic interactive image analyzer. Figures were expressed as percentage of attachment. DNA synthesis was estimated by measuring the amount of [3H]‐thymidine incorporation into trichloroacetic acid (TCA) insoluble cell precipitates. The specific activity of alkaline phosphatase was assayed using p‐nitrophenylphosphate as a substrate. The ability of the cells to synthesize osteocalcin was investigated in serum‐free culture medium using the ELSA‐OST‐NAT immunoradiometric kit. After 3 h of culture, the percentage of cellular attachment did not differ significantly between specimens blasted with 180–300 μm particles and the turned specimens. All blasted surfaces showed significantly higher [3H]‐thymidine incorporation than the turned surfaces (P<0.05), with the highest on the surfaces blasted with 180–300 μm particles. Osteocalcin synthesis by the cells in response to stimulation by 1,25(OH)2D3, was also significantly greater (P<0.05) on the surfaces blasted with TiO2 particles. However, analysis of alkaline phosphatase activity disclosed no significant differences among the four surface modifications. It is concluded that in this cellular model, the proliferation and differentiation of cells derived from human mandibular bone is enhanced by surface roughness of the titanium implant. However, increasing the size of the blasting particles to 300 μm does not further increase the initial attachment of the cells compared to turned surfaces and those blasted with 63–90 μm particles.
Overdenture attachment selection and the loading of implant and denture‐bearing area. Part 1: In vivo verification of stereolithographic model
Authors: Heckmann Siegfried Martin , Wichmann Manfred Gerhard , Winter Werner , Meyer Martin , Weber Hans‐Peter
Published: March 2003

Abstract: Preliminary to a study investigating the force transfer from osseointegrated dental implants to the surrounding bone via various types of overdenture attachment, a stereolithographic model (SL‐model) was constructed and compared to an in vivo situation in order to confirm the validity of the modeling technique for the planned measurements of implant strain and denture‐bearing area loading. The SL‐model was generated using the patient’s computer tomographic data and duplicated in a material of known elastic properties. The model was fitted with sensors to measure strains in the peri‐implant bone and loading forces within the posterior mandibular bone, i.e. the denture‐bearing area of the mandible. Special telescopic copings were constructed to measure implant strain in this model as well as in vivo. Using these copings under identical overdenture loading conditions, the strains measured at the implants in vivo and in vitro were the same and never exceeded a tolerance of two standard deviations or a mean difference of −8.5% of the in vitro value. This indicates that the model was reliable for the measurement of implant strain. Denture‐bearing area loading within the alveolar ridge cannot be measured in vivo. Instead, a method of extrapolating in vivo denture‐bearing area loading figures from implant strain readings was developed and tested (better than 90% accuracy). These in vivo extrapolated figures were then compared to in vitro readings under otherwise identical loading conditions. The result indicated that the SL‐model is reliable for measurements of denture‐bearing area loading with an error of 10 to 20%.
The use of reduced healing times on ITI® implants with a sandblasted and acid‐etched (SLA) surface:
Authors: Cochran David L. , Buser Daniel , Ten Bruggenkate Christian M. , Weingart Dieter , Taylor Thomas M. , Bernard Jean‐Pierre , Peters Françoise , Simpson James P.
Published: March 2003

Summary: ITI® dental implants are available with two bone‐anchoring surfaces, a titanium plasma‐sprayed (TPS) surface, and a recently introduced sandblasted and acid‐etched (SLA) surface. Cell culture and animal tests demonstrate that the SLA surface stimulates bone cell differentiation and protein production, has large amounts of bone‐to‐implant contact, and results in large removal torque values in functional testing of the bone contact. As a result of these studies, a prospective human clinical trial was initiated to determine whether the 4.1 mm diameter SLA ITI® solid screw implants could be predictably and safely restored as early as six weeks after implant placement surgery. The protocol restricted the use of the reduced healing time to a) healthy patients with sufficient bone volume to surround the implant, and b) those patients who had good bone quality (classes I‐III) at the implant recipient site. Patients with poorer bone quality (class IV) did not have restorations until 12 weeks after implant placement. The clinical trial is an ongoing multicenter trial, with six centers in four countries, and with follow‐up over five years. The primary outcome variable was abutment placement with a 35 Ncm force, with no countertorque and no pain or rotation of the implant. A secondary outcome was implant success, as defined by no mobility, no persistent pain or infection, and no peri‐implant radiolucency. To date, 110 patients with 326 implants have completed the one‐year post‐loading recall visit, while 47 patients with 138 implants have completed the two‐year recall. Three implants were lost prior to abutment connection. Prosthetic restoration was commenced after shortened healing times on 307 implants. The success rate for these implants, as judged by abutment placement, was 99.3% (with an average healing time of 49 days). Life table analyses demonstrated an implant success rate of 99.1%, both for 329 implants at one year and for 138 implants at two years. In the 24‐month period after restoration, no implant losses were reported for the 138 implants. These results demonstrate that, under defined conditions, solid screw ITI® implants with an SLA endosseous surface can be restored after approximately six weeks of healing with a high predictability of success, defined by abutment placement at 35 Ncm without countertorque, and with subsequent implant success rates of greater than 99% two years after restoration.
Histomorphological evaluation of loaded plate‐form and root‐form implants in Macaca mulatta monkeys
Authors: McCracken Michael , Lemons Jack E. , Jeffcoat Marjorie , Koth David L. , Fritz Michael E.
Published: March 2003

Abstract: As part of a long‐term evaluation of endosteal dental implants in primates, this paper describes the histological response to plate‐form and root‐form implants. Thirty‐six primates received 48 mandibular distal abutment implants. After healing, the implants were restored with fixed partial dentures, which remained in function for two years. A subset of the group was ligated at the gingival sulcus to biologically stress tissues supporting the implants. Crestal bone height around implants was quantified using digital subtraction radiographic techniques. The ligated implants lost more crestal bone than non‐ligated implants, as shown by ANOVA (P < 0.05). After retrieval, implants were embedded and sectioned for histomorphometric analysis including measurement of per cent osseointegration. Both plate‐form and root‐form non‐ligated implants demonstrated about 60% osseointegration. When ligated, plate‐form implants dropped to an average integration of only 34%, while root‐form implants maintained 62% integration, a significant difference. These data show that in this primate model, plate‐form and root‐form implants maintained integration while in function for two years. When stressed with ligation, root‐form implants maintained relative amounts of osseointegration, while per cent osseointegration of plate‐form implants decreased.
Effect of low‐power laser irradiation on bony implant sites
Authors: Dörtbudak Orhun , Haas Robert , Mailath‐Pokorny Georg
Published: March 2003

Abstract: This study was designed to examine the effects of low‐energy laser irradiation on osteocytes and bone resorption at bony implant sites. Five male baboons with a mean age of 6.5 years were used in the study. Four holes for accommodating implants were drilled in each iliac crest. Sites on the left side were irradiated with a 100 mW low‐energy laser (690 nm) for 1 min (6 Joule) immediately after drilling and insertion of four sandblasted and etched (Frialit®‐2 Synchro) implants. Five days later, the bone was removed en bloc and was evaluated histomorphometrically. The mean osteocyte count per unit area was 109.8 cells in the irradiated group vs. 94.8 cells in the control group. As intra‐individual cell counts varied substantially, osteocyte viability was used for evaluation. In the irradiated group, viable osteocytes were found in 41.7% of the lacuna vs. 34.4% in the non‐irradiated group. This difference was statistically significant at P < 0.027. The total resorption area, eroded surface, was found to be 24.9% in the control group vs. 24.6% in the irradiated group. This difference was not statistically significant. This study showed that osteocyte viability was significantly higher in the samples that were subjected to laser irradiation immediately after implant site drilling and implant insertion, in comparison to control sites. This may have positive effects on the integration of implants. The bone resorption rate, in contrast, was not affected by laser irradiation.
Bone collected during dental implant surgery: a clinical and histological study
Authors: Young Malcolm Peter Jackson , Worthington Helen Victoria , Lloyd Richard Ernest , Drucker David Bernard , Sloan Philip , Carter Duncan Howard
Published: March 2003

Abstract: Bone traps vary in design, although the effect of pore size on the nature of the debris collected in vivo has not yet been established. The aims of this study were 1) to compare the clinical performance of two bone collectors during implant surgery, ii) to establish the mass of tissue collected by each device, and iii) to characterize the nature of the collected debris. Thirty‐eight patients (paired for implant site) were categorised into three clinical groups according to the site and the number of implants they were to receive. Patients underwent bone collection with the Frios bone trap® or the Osseous Coagulum Trap® according to a randomisation sequence. The samples were fixed in formalin, frozen, freeze‐dried and weighed. Material from each sample was embedded in paraffin wax and stained with haematoxylin and eosin. All sections were examined by optical microscopy and the proportion of bone to coagulum was established histomorphometrically. During surgery, the Frios bone trap® blocked once and the Osseous Coagulum Trap® blocked 11 times. In all cases where blockage occurred, excess coagulum was apparent. All the samples that were collected by the Frios bone trap® contained bone and coagulum, with a mean proportion of 90.6% bone. With regard to the Osseous Coagulum Trap®, one sample contained no bone and two samples contained only trace amounts of bone; the remaining samples contained a mean proportion of 67.3% bone. Pore size affects both clinical performance and the histological composition of the debris collected, and this might have important implications if used as an augmentation material.
Microbiological findings and host response in patients with peri‐implantitis
Authors: Hultin Margareta , Gustafsson Anders , Hallström Hadar , Johansson L‐Å. , Ekfeldt Anders , Klinge Björn
Published: March 2003

Abstract: The aim of the present study was to characterise microbiota and inflammatory host response around implants and teeth in patients with peri‐implantitis. We included 17 partly edentulous patients with a total of 98 implants, of which 45 showed marginal bone loss of more than three fixture threads after the first year of loading. Nineteen subjects with stable marginal tissue conditions served as controls. Oral hygiene, gingival inflammation, and probing pocket depth were evaluated clinically at teeth and implants. Microbiological and crevicular fluid samples were collected from five categories of sites: 1) implants with peri‐implantitis (PI), 2) stable implants (SI) in patients with both stable and peri‐implantitis implants, 3) control implants (CI) in patients with stable implants alone, 4) teeth in patients (TP) and 5) controls (TC). Crevicular fluid from teeth and implants was analysed for elastase activity, lactoferrin and IL‐1β concentrations. Elastase activity was higher at PI than at CI in controls. Lactoferrin concentration was higher at PI than at SI in patients with peri‐implantitis. Higher levels of both lactoferrin and elastase activity were found at PI than at teeth in patients. The concentrations of IL‐1β were about the same in the various sites. Microbiological DNA‐probe analysis revealed a putative periodontal microflora at teeth and implants in patients and controls. Patients with peri‐implantitis harboured high levels of periodontal pathogens, Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Bacteroides forsythus and Treponema denticola. These findings indicate a site‐specific inflammation rather than a patient‐associated specific host response.
Interleukin‐1β, tumor necrosis factor‐α levels and neutrophil elastase activity in peri‐implant crevicular fluid
Authors: Ataoglu Hanife , Alptekin Nilgun Ozlem , Haliloglu Seyfullah , Gursel Mihtikar , Ataoglu Tamer , Serpek Behic , Durmus Ercan
Published: March 2003

Abstract:The aim of this study was to determine interleukin‐1β (IL‐1β), tumor necrosis factor‐α (TNF‐α) levels and neutrophil elastase (NE) activity in peri‐implant crevicular fluid (PICF) of smoker and nonsmoker patients, and to investigate their relationships with clinical parameters. A total of 42 endosseous root‐form dental implants of 14 patients were clinically examined by modified Plaque index (PI), modified Gingival index (GI) and probing depth (PD). Smoking habits of the patients were recorded. PICF of implants were collected by Periopaper strips and IL‐1β, TNF‐α levels were determined by enzyme‐linked immunosorbent assay (ELISA). NE was analyzed with a neutrophil specific chromogenic substrate,N‐methoxysuccinyl‐Ala‐Ala‐Pro‐Val‐p‐nitroanilide. The cytokine and enzyme levels in PICF were expressed as total amount/activity and as concentrations. NE activity in PICF significantly correlated with GI and PD, and IL‐1β levels with GI and PICF volume (P < 0.05). The correlations were stronger when the PICF levels were expressed as total IL‐1β amount and as total NE activity. The implants with inflamed gingiva (GI > 1) had higher levels of IL‐1β and NE activity than implants with noninflamed or slightly inflamed gingiva (GI ≤ 1) (P < 0.05). Total NE activity in implants with deep pockets (PD > 3 mm) was greater than the implants with shallow pockets (PD ≤ 3 mm) (P < 0.05). The implants of smoker patients had significantly lower PICF NE activity and IL‐1β levels, and significantly higher TNF‐α levels than the implants of nonsmokers (P < 0.05). The findings of the present study indicate that NE activity and IL‐1β levels in PICF may be used to measure implant health status of patients who do not smoke.
Outcome of implant therapy in relation to experienced loss of periodontal bone support
Authors: Hardt Christoph R. E. , Gröndahl Kerstin , Lekholm Ulf , Wennström Jan L.
Published: March 2003

Abstract: Purpose: The aim of this retrospective study was to analyse bone level alterations over a 5‐year period at implants in the maxillary posterior segments in patients with varying experience of periodontal bone loss in the natural dentition before implant placement.

Material and methods: 97 partially dentate patients with a total of 346 Brånemark® oral implants in the maxillary posterior segments were included. By assessing the degree of radiographic marginal bone loss in the remaining natural dentition at time of the implant therapy, an age‐related bone loss score (ArB‐score) was calculated for description of the patient's experience of periodontal destruction. The two end quartiles of the distribution of the subjects with regard to the ArB‐score were defined as Non‐Perio subjects and Perio subjects, respectively. The primary outcome variables were implant losses (implant failures) and radiographic peri‐implant bone loss over the 5‐year observation period.

Results: A total of 18 implants were lost during the 5 years, resulting in an overall failure rate of 5.2%. The corresponding failure rate was 3.3% for the Non‐Perio and 8.0% for the Perio patients. The peri‐implant bone loss from the time of abutment connection to 5 years averaged 1.8 mm (SD 0.7). Of the patients, 34% showed a mean bone loss of > 2 mm and 39% of all implants had experienced a bone loss of 2 mm at the 5‐year examination. The Non‐Perio and Perio patients showed a mean bone loss of 1.7 mm (0.8) and 2.2 mm (0.8), respectively. Multiple regression analysis revealed a statistically significant relationship between the ArB‐score and the peri‐implant bone level change from abutment connection to 5 years (P < 0.05). In all, 64% of Perio patients had a mean peri‐implant bone loss of > 2 mm from the time of abutment connection, compared to 24% for the Non‐Perio patients (P < 0.01). The percentage of implants showing 2 mm of bone loss between abutment connection and 5 years was 62% and 44% in the Perio and Non‐Perio groups, respectively (P = 0.055).

Conclusion: The results indicate that longitudinal bone loss around implants is correlated to previous experience of loss of periodontal bone support and that periodontitis susceptible subjects may show an increased implant failure rate.
Implant‐retained mandibular overdentures with ITI implants
Authors: Romeo Eugenio , Chiapasco Matteo , Lazza Andrea , Casentini Paolo , Ghisolfi Marco , Iorio Marco , Vogel Giorgio
Published: March 2003

Abstract: This prospective study has been designed to compare the results of immediate and delayed loading of implant‐retained mandibular overdentures after a 2‐year follow‐up. Twenty patients have been randomly divided into two groups. Group 1 patients (test group) received four ITI implants in the intraforaminal area of the mandible. Octa® abutments were immediately screwed on implants; 2 days after surgery, the implants were rigidly connected with a U‐shaped Dolder gold bar and loaded with an overdenture. Group 2 patients (control group) received, in the same area, the same type and number of implants, which were left to heal according to the standard protocol. At 3–4 months, Octa abutments were screwed on the implants and the same prosthetic procedure of the test group was applied. The minimum follow‐up period lasted 2 years, with recall appointments at 2 weeks, 1, 3, 6 months, 1 year and every following year postoperatively, evaluating: MPI, MBI, PD, Periotest® and radiographic peri‐implant bone resorption. Success criteria according to Albrektsson et al. were used. Only one implant out of the 40 of group 2 failed, whereas none failed in group 1. No statistical difference of the clinical parameters evaluated was noticed in the two groups. Therefore, immediate loading of implants, if connected with a U‐shaped bar, can provide the same results of the ‘traditional’ technique as far as osseointegration and short‐term survival rates of implants are concerned. Moreover, this method significantly shortens the treatment period, thus increasing patient satisfaction.
Platelets stimulate proliferation of bone cells: involvement of platelet‐derived growth factor, microparticles and membranes
Authors: Gruber Reinhard , Varga Franz , Fischer Michael B. , Watzek Georg
Published: March 2003

Abstract: Platelets have been implicated in accelerated bone regeneration in grafting applications. The beneficial effects of platelets may involve their ability to stimulate the proliferation of osteoblasts. We therefore determined the mitogenic response of human trabecular bone‐derived cells to human platelets and supernatants of thrombin‐activated platelets. We can show a ∼ 50‐fold increase in DNA‐synthesis of bone cells (BC) cultured in the presence of platelets as determined by [3H]‐thymidine incorporation. Preventing cell‐to‐cell contact by a membrane filter did not abrogate the stimulatory effect, indicating the release of soluble factor(s) that are mitogenic for BC. The lipid fraction of the platelets had no effect on [3H]‐thymidine uptake into the DNA of BC. Platelet‐released supernatant (PRS) increased the rate of [3H]‐thymidine incorporation to ∼ 20‐fold and retained 56% of their activity after incubation at 56 °C, and 27% at 100 °C, respectively. Neutralizing antibodies raised against platelet‐derived growth factor (PDGF) partially suppressed the mitogenic potential of PRS. Gel exclusion chromatography analysis showed that molecules ranging from 25 kDa to more than 70 kDa within the PRS can stimulate BC proliferation. The highest amount of PDGF was detected in fractions corresponding to a molecular weight of 28–37 kDa as determined by immunoassay. The mitogenic activity was not restricted to soluble growth factors because microparticles in the PRS and platelet membranes also increased BC proliferation. Our data indicate that native platelets, the respective PRS, microparticles, and platelet membranes can stimulate the mitogenic activity of BC, thereby contributing to the regeneration of mineralized tissue.
Characterization of bone resorbing activity in gingival crevicular fluid from patients with periodontitis
Authors: Rasmussen Lena , Hänström Lennart , Lerner Ulf H.
Published: March 2003

Background: In attempts to elucidate factors stimulating bone resorption in patients with different inflammatory diseases in the vicinity of the skeleton, e.g., peridontal disease and rheumatoid arthritis, we are investigating the presence of bone‐resorbing activity in a variety of inflammatory exudates. The aim of the present study was to characterize the bone‐resorbing activity present in patients with periodontitis.

Methods: Bone‐resorbing activity was assessed in gingival crevicular fluids (GCFs) collected from patients with periodontitis and from patients with no signs of gingivitis. Bone‐resorbing activity was evaluated by analyzing the capacity of GCFs to stimulate the release of minerals and the breakdown of bone matrix proteins in cultured neonatal mouse calvariae. The concentrations of IL‐1α, IL‐1β and PGE2 were determined with ELISA and RIA techniques, respectively.

Results: GCF eluates from 24 different healthy sites caused a 1.23±0.05 fold stimulation of 45Ca release, whereas GCF eluates from 45 different diseased (periodontitis) sites caused a 2.46±0.10 fold stimulation. The effect on 45Ca release was time‐ and concentration‐dependent, inhibited by 3 different osteoclast inhibitors and associated with enhanced release of
3H from [3H]‐proline‐labelled bones. The activity in GCF causing enhanced 45Ca release was unaffected, or in some samples partially reduced, by ultrafiltration using a filter with a molecular weight cut‐off of 3000 Daltons. The bone‐resorbing activity was temperature sensitive (+90°C, 10 min). The concentrations of prostaglandin E2 (PGE2) in the diluted GCF eluates, used in the bone resorption bioassay, were too low to be responsible for the release of 45Ca. Antisera specifically neutralizing human IL‐1α inhibited the stimulatory effect of GCF pooled from several diseased sites. The specific, recombinant human IL‐1 receptor antagonist completely inhibited the effect of pooled GCFs. GCF

eluates from diseased sites contained human IL‐1α and IL‐1β at concentrations of 1838±294 pg/ml and 512±91 pg/ml, respectively.

Conclusions: These data show that GCF contains activity(ies) stimulating osteoclastic bone resorption in vitro. The factor primarily responsible for this activity seems to be IL‐1α, but IL‐1α is not the sole activator of bone resorption in GCF.
Treatment of intrabony defects with resorbable materials, non‐resorbable materials and flap debridement
Authors: Zybutz Michael D. , Laurell Lars , Rapoport Darrin A. , Rutger Persson G.
Published: March 2003

Background: Different types of barriers are used in guided tissue regenerative procedures.

Aim:

This prospective study compared resorbable citric acid ester softened polylactic acid membranes (RM) and non‐resorbable expanded polytetrafluoroethylene (ePTFE) barriers (NRM) in GTR treatment of intrabony defects.

Methods: 29 subjects were randomly assigned to the RM group or NRM group. Each patient received one GTR procedure. An open flap debridement (FD) was performed at another site 2 weeks later to evaluate healing potential. Clinical treatment outcomes were finally evaluated 12 months after surgery for changes of pocket depth PD, probing attachment level PAL, and probing bone level PBL, and radiographically for bone change using standardised radiographs.

Results: No differences in healing patters after surgery were found between patients in the 2 study groups as evaluated from the FD surgical procedures. NRM treated sites showed less signs of post‐surgical inflammation during the 1st 4 weeks of healing than did RM treated sites (p<0.05). GTR‐treated defects in the RM group, initially 7.0±2.2 mm deep, showed PD reduction of 3.3±2.2 mm, PAL gain of 2.4±1.8 mm, PBL gain of 2.4±3.7 mm (28%) and a radiographic bone fill of 2.3±2.4 mm. Defects treated with the NRM exhibited PD reduction of 3.1±2.1 mm, PAL gain of 2.4±0.8 mm, PBL gain of 2.2±1.7 mm (25%) and a radiographic bone fill of 3.3±2.2 mm. All improvements were statistically significant (p<0.01) but there was no difference between RM and NRM treatments for any of the efficacy variables. The results of this study indicated that there was no clinically significant difference in treatment outcomes following GTR treatment of intrabony defects with citric acid ester softened polylactic acid membranes as compared to ePTFE barriers. The overall mean inter‐proximal vertical bone defect fill at 12 months as assessed from intra‐oral radiographs was 44% of the original mean defect depth.

Conclusions: Thus, no clinically significant difference in treatment outcomes was observed following GTR treatment of intrabony defects with citric acid ester softened polylactic acid membranes or ePTFE barriers.
Dental and periodontal status of Sjögren's syndrome
Authors: Boutsi Elizabeth A. , Paikos Spyros , Dafni Urania G. , Moutsopoulos Haralampos M. , Skopouli Fotini N.
Published: March 2003

Background: Sjögren's syndrome (SS) is one of the most common systemic autoimmune diseases in middle‐aged women. The present study had the aim to examine the dental and periodontal condition in patients with SS in comparison with disease controls and to evaluate the influence of reduced salivary flow in the periodontal tissues.

Method: We examined 24 patients with primary or secondary SS in comparison with 27 patients who had another autoimmune disease but no signs or symptoms of SS, as well as with 29 subjects who had a subjective feeling of xerostomia or xerophthalmia without exhibing an underlying disease. The clinical evaluation included examination of the oral mucosa, determination of missing, decayed and filled teeth, fixed or removable prosthetic appliances, plaque index, gingival index, probing pocket depth, probing attachment level, oral hygiene habits and frequency of dental visits. Statistical analysis was performed using the 2‐tailed Fisher exact and Kruskal‐Wallis tests.

Results: No significant difference was found in the dental or periodontal condition of the 3 groups. The number of teeth, feelings and distal or mesial decay lesions correlated negatively with age, while the number of fixed prosthetic appliances correlated positively. The salivary flow was statistically lower in patients with SS and exhibited a negative correlation with the number of cervical decay lesions. It was also found that SS patients had better oral hygiene habits than subjects of the control groups.

Conclusions: No significant difference could be detected concerning the dental and periodontal status of SS patients, compared with that of patients with other immune diseases as well as with that of controls who had subjective xerostomia.
Analysis of saliva for periodontal diagnosis
Authors: Kaufman Eliaz , Lamster Ira B.
Published: March 2003

Background: This review examines salivary constituents as potential diagnostic tests for periodontal disease. Saliva is a fluid that is readily available and contains locally‐produced microbial and host response mediators, as well as systemic (serum) markers that may prove to be an aid in the diagnosis of periodontal disease.

Methods: A medline search was conducted and the relevant literature concerning the applications of saliva for periodontal diagnosis was reviewed.

Results: Based on the literature, salivary markers that have been studied as potential diagnostic tests for periodontal disease include proteins of host origin (i.e., enzymes, immunoglobulins), phenotypic markers, host cells, hormones (cortisol), bacteria and bacterial products, ions and volatile compounds.

Conclusions: A number of markers show promise as sensitive measures of disease and the effectiveness of therapy. At this time, host‐derived enzymes and other inflammatory mediators orginating from the gingival crevice appear to hold the greatest promise as salivary diagnostic tests for periodontal disease. Longer‐term longitudinal studies, however, are required to establish the relationship between specific markers and progression of periodontal disease. Furthermore, analysis of saliva may offer a cost‐effective approach to assessment of periodontal disease in large populations.
Effect of 3 dentifrices containing triclosan and various additives
Authors: Nogueira‐Filho G. R. , Toledo S. , Cury J. A.
Published: March 2003

Background: The antiplaque and antigingivitis effect of 3 dentifrices was evaluated using the 21‐day partial‐mouth experimental model of gingivitis.

Method: 25 volunteers took part in this cross‐over, double‐blind study, carried out in 4 phases of 21 days each. For each phase of the study, a toothshield of the IV quadrant was constructed for each volunteer. 2 antiplaque dentifrices from the market, one containing triclosan + pvm/ma and the other triclosan + Zn, were compared with an experimental formulation and its placebo. The experimental dentifrice contained triclosan + pvm/ma + Zn + PPi and the placebo (control) did not contain these substances. The subjects were stratified according to their whole‐mouth baseline plaque (PI), gingivitis (GI) and bleeding (BI) index scores, and then randomly assigned to 1 of 4 dentifrices. During each phase, while the volunteers brushed their teeth with one of the dentifrices, the IV quadrant was protected by the toothshield filled with the dentifrice used. After each phase, dental plaque, gingivitis and bleeding indices were determined.

Results: The results showed that only the formulation containing triclosan + pvm/ma + Zn + PPi was able to reduce PI (28.8%), GI (35.9%) and BI (30.4%) in comparison with controls (p<0.05).

Conclusions: The data suggest that a dentifrice containing the combination of triclosan + pvm/ma + Zn + PPi should be formulated for dental plaque control.
Factors influencing phenytoin‐induced gingival enlargement
Authors: Majola M. P. , McFadyen M. L. , Connolly C. , Nair Y. P. , Govender M. , Laher M. H. E.
Published: March 2003

Aim: To ascertain the prevalence and severity of phenytoin‐induced gingival enlargement (PIGE) as well as the relationship between PIGE and risk factors.

Method: An outpatient population of patients on phenytoin treatment and attending the epilepsy clinic at Prince Mshiyeni Memorial Hospital (PMMH) in Durban, South Africa, was requested to participate. A structured questionnaire was used to collect data on patients' demographics, social habits (e.g., drinking and smoking), dental and oral hygiene practices and medication history. Gingival enlargement, dental plaque and gingival bleeding was also measured to assess gingival health. Venous blood was collected for serum folate and phenytoin serum levels measurements. A regression analyses was then undertaken to ascertain the association between PIGE and the risk factors. Factors tested for correlation were serum phenytoin and folate levels, age, bacterial plaque, gingival inflammation, toothbrushing, smoking and alcohol consumption. The association between PIGE and the risk factors was assessed either individually, i.e., as a single entity or in combination – multifactorially.

Results: Of the 134 patients studied, 62% had PIGE scores 1, while 8% had a PIGE score of zero. With the exception of plaque, which showed a moderate association with PIGE (r=0.4), no other factor on its own was statistically significantly related to PIGE. In the multiple linear regression analysis, factors which on their own did not have a strong influence became more important. Bacterial plaque (p=0.0001), younger age (p=0.01) and higher free serum phenytoin levels (p=0.03), were associated with PIGE. Although known to be associated with periodontal diseases, smoking and alchol, (p=0.03 and p=0.04 respectively), appeared to give some protection against PIGE.

Conclusion: Risk factors associated with PIGE may have a synergistic effect. Bacterial plaque, however, appears the most important determinant of PIGE severity. This latter finding emphasises the importance of instituting a preventive plaque‐control programme, particularly in young patients on phenytoin therapy.
Masticatory mucosa in subjects with different periodontal phenotypes
Authors: Müller Hans‐Peter , Heinecke Achim , Schaller Nils , Eger Thomas
Published: March 2003

Aims: The aim of the present investigation was to study thickness of masticatory mucosa and gingival width in subjects with different periodontal phenotypes.

Methods: Periodontal phenotypes were defined with the aid of cluster analysis of standardised parameters including mean gingival thickness and width as well as ratio of crown width to its length at maxillary canines, lateral and central incisors of 40 young adults with healthy periodontal conditions.

Results: 3 groupings could be observed. Clusters A1 and A2 comprised 75% of all subjects. They were characterised by thin gingiva and a slender tooth form. Clusters A1 and A2 were differentiated by gingival width. Cluster B comprised 11 subjects with relatively thick and wide gingiva and a quadratic tooth shape. In general, characteristics of the frontal sextant in the maxilla were also found in other parts of the dentition. Thus, mean thickness of masticatory mucosa as well as gingival width and crown form differed significantly among clusters. In addition, cluster B subjects had a significantly greater mean periodontal probing depth. Multiple linear regression analysis was employed to identify significant factors influencing palatal mucosal thickness. Women had considerably thinner palatal mucosa than men. Furthermore, cluster affiliation had a significant influence on thickness of palatal mucosa. Thickest tissue was found in the premolar region, whereas the mucosa over the root prominence of the first molar represented an anatomical barrier for graft harvesting.

Conclusions: Thickness of masticatory mucosa strongly depends on gender and the periodontal phenotype.