Deproteinized bovine bone mineral in marginal defects at implants installed immediately into extraction sockets: an experimental study in dogs

Aim: To evaluate the influence of deproteinized bovine bone mineral (DBBM) particles concomitant with the placement of a collagen membrane on alveolar ridge preservation and on osseointegration of implants placed into alveolar sockets immediately after tooth extraction. Material and methods: The pulp tissue of the mesial roots of ₃P₃ was removed in six Labrador dogs and the root canals were filled. Flaps were elevated in the right side of the mandible, and the buccal and lingual alveolar bony plates were exposed. The third premolar was hemi‐sectioned and the distal root was removed. A recipient site was prepared and an implant was placed lingually. After implant installation, defects of about 0.6 mm wide and 3.1 mm depth resulted at the buccal aspects of the implant, both at the test and at the control sites. The same surgical procedures and measurements were performed on the left side of the mandible. However, DBBM particles with a size of 0.25–1 mm were placed into the remaining defect concomitant with the placement of a collagen membrane. Results: All implants were integrated into mature bone. No residual DBBM particles were detected at the test sites after 4 months of healing. Both the test and the control sites showed buccal alveolar bone resorption, 1.8±1.1 and 2.1±1 mm, respectively. The most coronal bone‐to‐implant contact at the buccal aspect was 2±1.1 an 2.8±1.3 mm, at the test and the control sites, respectively. This difference in the distance was statistically significant. Conclusion: The application of DBBM concomitant with a collagen membrane to fill the marginal defects around implants placed into the alveolus immediately after tooth extraction contributed to improved bone regeneration in the defects. However, with regard to buccal bony crest preservation, a limited contribution of DBBM particles was achieved. To cite this article:
Caneva M, Botticelli D, Pantani F, Baffone GM, Rangel IG Jr, Lang NP. Deproteinized bovine bone mineral in marginal defects at implants installed immediately into extraction sockets: an experimental study in dogs.
Clin. Oral Impl. Res. 23 , 2012; 106–112.
doi: 10.1111/j.1600‐0501.2011.02202.x     

Hard tissue formation adjacent to implants of various size and configuration immediately placed into extraction sockets: an experimental study in dogs

Objectives: To evaluate the influence of implant size and configuration on osseointegration in implants immediately placed into extraction sockets. Material and methods: Implants were installed immediately into extraction sockets in the mandibles of six Labrador dogs. In the control sites, cylindrical transmucosal implants (3.3 mm diameter) were installed, while in the test sites, larger and conical (root formed, 5 mm diameter) implants were installed. After 4 months of healing, the resorptive patterns of the alveolar crest were evaluated histomorphometrically. Results: With one exception, all implants were integrated in mineralized bone, mainly composed of mature lamellar bone. The alveolar crest underwent resorption at the control as well as at the test implants. This resorption was more pronounced at the buccal aspects and significantly greater at the test (2.7±0.4 mm) than at the control implants (1.5±0.6 mm). However, the control implants were associated with residual defects that were deeper at the lingual than at the buccal aspects, while these defects were virtually absent at test implants. Conclusions: The installment of root formed wide implants immediately into extraction sockets will not prevent the resorption of the alveolar crest. In contrast, this resorption is more marked both at the buccal and lingual aspects of root formed wide than at standard cylindrical implants. To cite this article:
Caneva M, Salata LA, de Souza SS, Bressan E, Botticelli D, Lang NP. Hard tissue formation adjacent to implants of various size and configuration immediately placed into extraction sockets: an experimental study in dogs.
Clin. Oral Impl. Res. 21 , 2010; 885–895.
doi: 10.1111/j.1600‐0501.2010.01931.x     

Instrument for extraction socket measurement in immediate implant installation

The aim of the present study was to create an instrument and a computer program for measurement of extraction sockets and for planning of the immediate replacement of teeth using screw-shaped dental implants. Ten titanium screw-shaped Osteofix Dental Implant System implants (Osteofix, Oulu, Finland) were immediately installed after extraction in nine patients, four women and five men (age 17-62 years). The measurements of fresh extraction sockets were taken at six points (mesio-buccal, buccal, disto-buccal, disto-lingual, lingual and mesio-lingual) using an instrument created by the author. The area of no contact between bone and dental implant was 11-40% (mean 31%, SD 9%), calculated by computer program. If less than 30% of the implant surface area would be in contact with the bone, immediate replacement was abandoned because sufficient primary stability could not be achieved. Guided bone regeneration was promoted by covering the implant and bone defect with deproteinized bovine bone mineral (Bio-Oss, Geistlich AG, Wolhusen, Switzerland) and bioresorbable collagen membrane (Bio-Gide, Geistlich AG), fixed in place with resorbable pins (Resor Pin, Geistlich AG). After 6 months a considerable, statistically significant (P < 0.05) defect reduction of 90% (SD 7%) was noted. It was concluded that an instrument and a computer program created for extraction socket measurement are useful in some borderline cases when there is lack of bone and the success of one-stage implantation is doubtful.     

Immediate implants at fresh extraction sockets: bone healing in four different implant systems

Objectives: To describe the differences in bone healing, when placing four different implant systems in fresh extraction sockets.
Material and Methods: Eight beagle dogs received implants randomly installed into the distal socket of three P3 and four P4. Four-implant systems were evaluated. Each animal provided four test implant sites. All animals were sacrificed at 6 weeks after implant placement, providing specimens for histo-morphometric analysis of bone to implant contact (BIC), bone area, new bone formation, as well as histometric measurements of the ridge alterations.
Results: No statistically significant difference was observed among the four-implant systems. The mean BIC % ranged between 58.5% and 72.1%. Bone modelling of the buccal plate was marked and amounted approximately to 2.5 mm, independently of the system used.
Conclusion: This study failed to demonstrate differences in the healing pattern after 6 weeks when placing four different implant systems in fresh extraction sockets. In spite of achieving predictable osteointegration with the four implants studied, the occurrence of buccal bone resorption may limit the use of this surgical approach.     

Effect of immediate or delayed loading following immediate placement of implants with a modified surface

Objective: To evaluate the effect of the timing of loading on bone‐to‐implant contact (BIC) following immediate placement of implants with a hydrophilic sandblasted, large‐grit and acid‐etched surface (modSLA) into fresh extraction sockets in a minipig model. Material and methods: Six minipigs were used in this study. In each hemi‐mandible, two conical shape implants (TE, Straumann implants) with a hydrophilic surface (modSLA) were placed in fresh extraction sockets. In one side of the mandible (control), two implants were immediately placed in fresh extraction sockets. The implants were loaded after 4 weeks of healing. At the contralateral side (test), two implants were immediately placed and loaded. After 8 weeks of healing, the animals were sacrificed and histologically analysed. Results: During the experimental period, no implants were lost and all of them presented to be osseointegrated. The percentage of BIC was similar in both groups: 66.1% and 65.1% for the control and test group, respectively. Furthermore, the distance from the shoulder of the implant to bone crest and the distance from the shoulder to the first BIC were similar in both groups. Conclusion: Immediate implant placement and loading showed similar BIC with immediate placement and delayed loading when implants with a modSLA surface were used. Both procedures showed similar buccal bone crest levels, which presented some resorption irrespective of the treatment modality. To cite this article:
Liñares A, Mardas N, Dard M, Donos N. Effect of immediate or delayed loading following immediate placement of implants with a modified surface.
Clin. Oral Impl. Res. 22 , 2011; 38–46.
doi: 10.1111/j.1600‐0501.2010.01988.x     

Collagen membranes at immediate implants: a histomorphometric study in dogs

Aim: To evaluate the influence of resorbable membranes on hard tissue alterations and osseointegration at implants placed into extraction sockets in a dog model. Material and methods: In the mandibular premolar region, implants were installed immediately into the extraction sockets of six Labrador dogs. Collagen‐resorbable membranes were placed at the test sites, while the control sites were left uncovered. Implants were intended to heal in a submerged mode. After 4 months of healing, the animals were sacrificed, and ground sections were obtained for histomorphometric evaluation. Results: After 4 months of healing, a control implant was not integrated (n=5). Both at the test and at the control sites, bone resorption occurred. While the most coronal bone‐to‐implant contact was similar between the test and the control sites, the alveolar bone crest outline was maintained to a higher degree at the buccal aspect of the test sites (loss: 1.7 mm) compared with the control sites (loss: 2.2 mm). Conclusions: The use of collagen‐resorbable membranes at implants immediately placed into extraction sockets contributed to a partial (23%) preservation of the buccal outline of the alveolar process. To cite this article:
Caneva M, Botticelli D, Salata LA, Souza SLS, Carvalho Cardoso L, Lang NP. Collagen membranes at immediate implants: a histomorphometric study in dogs.
Clin. Oral Impl. Res. 21 , 2010; 891–897.
doi: 10.1111/j.1600‐0501.2010.01946.x     

Influence of implant positioning in extraction sockets on osseointegration: histomorphometric analyses in dogs

Aim: To evaluate the influence of implant positioning into extraction sockets on osseointegration. Material and methods: Implants were installed immediately into extraction sockets in the mandibles of six Labrador dogs. In the control sites, the implants were positioned in the center of the alveolus, while in the test sites, the implants were positioned 0.8 mm deeper and more lingually. After 4 months of healing, the resorptive patterns of the alveolar crest were evaluated histomorphometrically. Results: All implants were integrated in mineralized bone, mainly composed of mature lamellar bone. The alveolar crest underwent resorption at the control as well as at the test sites. After 4 months of healing, at the buccal aspects of the control and test sites, the location of the implant rough/smooth limit to the alveolar crest was 2±0.9 mm and 0.6±0.9 mm, respectively (P<0.05). At the lingual aspect, the bony crest was located 0.4 mm apically and 0.2 mm coronally to the implant rough/smooth limit at the control and test sites, respectively (NS). Conclusions: From a clinical point of view, implants installed into extraction sockets should be positioned approximately 1 mm deeper than the level of the buccal alveolar crest and in a lingual position in relation to the center of the alveolus in order to reduce or eliminate the exposure above the alveolar crest of the endosseous (rough) portion of the implant. To cite this article:
Caneva M, Salata LA, de Souza SS, Baffone G, Lang NP, Botticelli D. Influence of implant positioning in extraction sockets on osseointegration: histomorphometric analyses in dogs.
Clin. Oral Impl. Res. 21 , 2010; 43–49.     

The clinical use of deproteinized bovine bone mineral on bone regeneration in conjunction with immediate implant installation

Twenty-one c.p. titanium screw-shaped implants were immediately installed after extraction and thorough curettage of the alveoli in 15 patients. Granules of deproteinized bovine bone of 0.25-1.0 mm diameter were used to fill the remaining defect when the distance of the defect wall to the implant surface was > 3 mm. Dimensional measurements of the defect height and width were made with a pocket probe. Fourteen sites in the upper jaw and 7 sites in the lower jaw were thus treated. The mean defect depth varied between 7 mm vestibularly and 10 mm mesially. The mucoperiosteal flaps were hermetically closed. At re-entry, the particles were packed and firmly attached but still distinguishable from the surrounding bone. Of the 21 sites treated, 5 sites had an exposure of the implant cover screw during the healing period. An exposure of the granular material occurred in 4 sites, but loss of granules in only 3. Even in these sites no signs of infection or inflammation of the soft tissues were observed. At re-entry after 6 months, 10 sites were completely and 9 partially filled. For the partial fills, the mean remaining defect height was 1.6 mm (range: 0.6-3.0 mm). Two sites showed an increased defect of respectively 2.4 and 4.8 mm. No fixtures were lost. The present results indicate that deproteinized bovine bone is a safe filling material to fill remaining defects around implants installed in fresh extraction sockets.     

Influence of a microgrooved collar design on soft and hard tissue healing of immediate implantation in fresh extraction sites in dogs

Objective: This study compared the alveolar bone reduction after immediate implantation using microgrooved and smooth collar implants in fresh extracted sockets. Material and methods: Four mongrel dogs were used in this study. The full buccal and lingual mucoperiosteal flaps were elevated and the third and fourth premolars of the mandible were removed. The implants were installed in the fresh extracted sockets. The animals were sacrificed after a 3‐month healing period. The mandibles were dissected and each implant site was removed and processed for a histological examination. Results: During healing, the marginal gaps in both groups, which were present between the implant and the socket walls at implantation, disappeared as a result of bone filling and resorption of the bone crest. The buccal bone crests were located apical of its lingual counterparts. At the 12‐week interval, the mean bone–implant contact in the microgrooved group was significantly higher than that of the turned surface group. From the observations in some of the microgrooved groups, we have found bone attachment to the 12 μm microgrooved surface and collagen fibers perpendicular to the long axis of the implants over the 8 μm microgrooved surface. Conclusion: Within the limitations of this study, microgrooved implants may provide more favorable conditions for the attachment of hard and soft tissues and reduce the level of marginal bone resorption and soft tissue recession. To cite this article:
Shin S‐Y., Han D‐H. Influence of microgrooved collar design on soft and hard tissue healing of immediate implantation in fresh extraction sites in dogs.
Clin. Oral Impl. Res. 21 , 2010; 804–814.
doi: 10.1111/j.1600‐0501.2010.01917.x     

Socket grafting with the use of autologous bone: an experimental study in the dog

Background: Studies in humans and animals have shown that following tooth removal (loss), the alveolar ridge becomes markedly reduced. Attempts made to counteract such ridge diminution by installing implants in the fresh extraction sockets were not successful, while socket grafting with anorganic bovine bone mineral prevented ridge contraction. Aim: To examine whether grafting of the alveolar socket with the use of chips of autologous bone may allow ridge preservation following tooth extraction. Methods: In five beagle dogs, the distal roots of the third and fourth mandibular premolars were removed. The sockets in the right or the left jaw quadrant were grafted with either anorganic bovine bone or with chips of autologous bone harvested from the buccal bone plate. After 3 months of healing, biopsies of the experimental sites were sampled, prepared for buccal–lingual ground sections and examined with respect to size and composition. Results: It was observed that the majority of the autologous bone chips during healing had been resorbed and that the graft apparently did not interfere with socket healing or processes that resulted in ridge resorption. Conclusion: Autologous bone chips placed in the fresh extraction socket will (i) neither stimulate nor retard new bone formation and (ii) not prevent ridge resorption that occurs during healing following tooth extraction. To cite this article:
Araújo MG, Lindhe J. Socket grafting with the use of autologous bone: an experimental study in the dog.
Clin. Oral Impl. Res. 22 , 2011; 9–13.
doi: 10.1111/j.1600‐0501.2010.01937.x     

Magnesium-enriched hydroxyapatite at immediate implants: a histomorphometric study in dogs

Aim: To evaluate the influence of magnesium‐enriched hydroxyapatite (MHA) (SintLife^®) on bone contour preservation and osseointegration at implants placed immediately into extraction sockets. Material and methods: In the mandibular pre‐molar region, implants were installed immediately into extraction sockets of six Labrador dogs. MHA was placed at test sites, while the control sites did not receive augmentation materials. Implants were intended to heal in a submerged mode. After 4 months of healing, the animals were sacrificed, and ground sections were obtained for histomorphometric evaluation. Results: After 4 months of healing, one control implant was not integrated leaving n=5 test and control implants for evaluation. Both at the test and the control sites, bone resorption occurred. While the most coronal bone‐to‐implant contact was similar between test and control sites, the alveolar bony crest outline was maintained to a higher degree at the buccal aspect of the test sites (loss: 0.7 mm) compared with the control sites (loss: 1.2 mm), even though this difference did not reach statistical significance. Conclusions: The use of MHA to fill the defect around implants placed into the alveolus immediately after tooth extraction did not contribute significantly to the maintenance of the contours of the buccal alveolar bone crest. To cite this article:
Caneva M, Botticelli D, Stellini E, Souza SLS, Salata LA, Lang NP. Magnesium‐enriched hydroxyapatite at immediate implants: a histomorphometric study in dogs.
Clin. Oral Impl. Res. 22 , 2011; 512–517
doi: 10.1111/j.1600‐0501.2010.02040.x     

Immediate transmucosal implant placement in molar extraction sites: a 12-month prospective multicenter cohort study

Aim: To assess the clinical and radiographic outcomes of immediate transmucosal placement of implants into molar extraction sockets. Study design: Twelve‐month multicenter prospective cohort study. Material and methods: Following molar extraction, tapered implants with an endosseous diameter of 4.8 mm and a shoulder diameter of 6.5 mm were immediately placed into the sockets. Molars with evidence of acute periapical pathology were excluded. After implant placement and achievement of primary stability, flaps were repositioned and sutured allowing a non‐submerged, transmucosal healing. Peri‐implant marginal defects were treated according to the principles of guided bone regeneration (GBR) by means of deproteinized bovine bone mineral particles in conjunction with a bioresrobable collagen membrane. Standardized radiographs were obtained at baseline and 12 months thereafter. Changes in depth and width of the distance from the implant shoulder (IS) and from the alveolar crest (AC) to the bottom of the defect (BD) were assessed. Results: Eighty‐two patients (42 males and 40 females) were enrolled and followed for 12 months. They contributed with 82 tapered implants. Extraction sites displayed sufficient residual bone volume to allow primary stability of all implants. Sixty‐four percent of the implants were placed in the areas of 36 and 46. GBR was used in conjunction with the placement of all implants. No post‐surgical complications were observed. All implants healed uneventfully yielding a survival rate of 100% and healthy soft tissue conditions after 12 months. Radiographically, statistically significant changes (P<0.0001) in mesial and distal crestal bone levels were observed from baseline to the 12‐month follow‐up. Conclusions: The findings of this 12‐month prospective cohort study showed that immediate transmucosal implant placement represented a predictable treatment option for the replacement of mandibular and maxillary molars lost due to reasons other than periodontitis including vertical root fractures, endodontic failures and caries.     

Bone regeneration in dehiscence-type defects at non-submerged and submerged chemically modified (SLActive) and conventional SLA titanium implants: an immunohistochemical study in dogs

Objectives: The aim of the present study was to evaluate bone regeneration in dehiscence‐type defects at non‐submerged and submerged titanium implants with chemically modified (mod) and conventional sandblasted/acid‐etched (SLA) surfaces. Material and Methods: Standardized buccal dehiscence defects were surgically created following implant site preparation in both the upper and lower jaws of 12 beagle dogs. Both types of implants were randomly assigned to either a non‐submerged or a submerged healing procedure. After 1, 2, 4, and 8 weeks, dissected blocks were processed for histomorphometrical [e.g. new bone height (NBH), per cent linear fill (PLF), percentage of bone to implant contact (BIC‐D), area of new bone fill (BF)] and immunohistochemical analysis. Results: At 8 weeks, non‐submerged and submerged SLA implants revealed significantly lower mean NBH (1.1±0.8–1.9±1.2 mm), PLF (27.7±20.3–46.0±28.5%), BIC‐D (26.8±10.4–46.2±16.2%), and BF (1.3±0.9–3.4±2.8 mm²) values than respective modSLA implants [NBH (2.6±0.8–4.3±0.1 mm), PLF (64.2±19.4–107.2±4.7%), BIC‐D (67.5±18.8–82.1±14.8%), BF (2.9±1.0–6.7±1.1 mm²)]. Within modSLA groups, significantly highest BF values were observed at submerged implants. Conclusion: It was concluded that (i) modSLA titanium surfaces promoted bone regeneration in acute‐type buccal dehiscence defects and (ii) a submerged healing procedure improved the outcome of healing additionally.     

Flap vs. “flapless” surgical approach at immediate implants: a histomorphometric study in dogs

Aim: To compare the remodeling of the alveolar process at implants installed immediately into extraction sockets by applying a flap or a “flapless” surgical approach in a dog model. Material and methods: Implants were installed immediately into the distal alveoli of the second mandibular premolars of six Labrador dogs. In one side of the mandible, a full‐thickness mucoperiosteal flap was elevated (control site), while contra‐laterally, the mucosa was gently dislocated, but not elevated (test site) to disclose the alveolar crest. After 4 months of healing, the animals were sacrificed, ground sections were obtained and a histomorphometric analysis was performed. Results: After 4 months of healing, all implants were integrated (n=6). Both at the test and at the control sites, bone resorption occurred with similar outcomes. The buccal bony crest resorption was 1.7 and 1.5 mm at the control and the test sites, respectively. Conclusions: “Flapless” implant placement into extraction sockets did not result in the prevention of alveolar bone resorption and did not affect the dimensional changes of the alveolar process following tooth extraction when compared with the usual placement of implants raising mucoperiosteal flaps. To cite this article:
Caneva M, Botticelli D, Salata LA, Souza SLS, Bressan E, Lang NP. Flap vs. “flapless” surgical approach at immediate implants: a histomorphometric study in dogs.
Clin. Oral Impl. Res. 21 , 2010; 1314–1319.
doi: 10.1111/j.1600‐0501.2009.01959.x     

Ridge alterations following immediate implant placement and the treatment of bone defects with Bio-Oss in an animal model

Background: Conflicting data exist on the outcome of placing Bio‐Oss® (Geitslich Pharm AG, Wolhausen, Switzerland) into extraction sockets. It is therefore relevant to study whether the incorporation of Bio‐Oss into extraction sockets would influence bone healing outcome at the extraction sites. Purpose: The aim of this study was to assess peri‐implant bone changes when implants were placed in fresh extraction sockets and the remaining defects were filled with Bio‐Oss particles in a canine mandible model. Materials and Methods: Six mongrel dogs were used in the study. In one jaw quadrant of each animal, the fourth mandibular premolars were extracted with an elevation of the mucoperiosteal flap; implants were then placed in the fresh extraction sockets and the remaining defects were filled with Bio‐Oss particles. After 4 months of healing, micro‐computed tomography at the implant sites was performed. Osseointegration was calculated as the percent of implant surface in contact with bone. Additionally, bone height was measured in the peri‐implant bone. Results: Average osseointegration was 28.5% (ranged between 14.8 and 34.2%). The mean crestal bone loss was 4.7 ± 2.1 mm on the buccal aspect, 0.4 ± 0.5 mm on the mesial aspect, 0.4 ± 0.3 mm on the distal aspect, and 0.3 ± 0.4 mm on the lingual aspect. Conclusion: The findings from this study demonstrated that the placement of implants and Bio‐Oss® particles into fresh extraction sockets resulted in significant buccal bone loss with low osseointegration.     

Soft tissues healing at immediate transmucosal implants placed into molar extraction sites with buccal self-contained dehiscences. A 12-month controlled clinical trial

Aim: To assess soft tissues healing at immediate transmucosal implants placed into molar extraction sites with buccal self-contained dehiscences.
Material and methods: For this 12-month controlled clinical trial, 15 subjects received immediate transmucosal tapered-effect (TE) implants placed in molar extraction sockets displaying a buccal bone dehiscence (test sites) with a height and a width of ≥3 mm, respectively. Peri-implant marginal defects were treated according to the principles of Guided Bone Regeneration (GBR) by means of deproteinized bovine bone mineral particles in conjunction with a bioresorbable collagen membrane. Fifteen subjects received implants in healed molar sites (control sites) with intact buccal alveolar walls following tooth extraction. In total, 30 TE implants with an endosseous diameter of 4.8 mm and a shoulder diameter of 6.5 mm were used. Flaps were repositioned and sutured, allowing non-submerged, transmucosal soft tissues healing. At the 12-month follow-up, pocket probing depths (PPD) and clinical attachment levels (CAL) were compared between implants placed in the test and the control sites, respectively.
Results: All subjects completed the 12-month follow-up period. All implants healed uneventfully, yielding a survival rate of 100%. After 12 months, statistically significantly higher ( P <0.05) PPD and CAL values were recorded around implants placed in the test sites compared with those placed in the control sites.
Conclusions: The findings of this controlled clinical trial showed that healing following immediate transmucosal implant installation in molar extraction sites with wide and shallow buccal dehiscences yielded less favorable outcomes compared with those of implants placed in healed sites, and resulted in lack of 'complete' osseointegration.     

Platelet-rich plasma may not provide any additional effect when associated with guided bone regeneration around dental implants in dogs

OBJECTIVE: The aim of this study was to evaluate histometrically bone healing in surgically created dehiscence-type defects around titanium implants treated with an association of platelet-rich plasma (PRP) and guided bone regeneration (GBR). MATERIALS AND METHODS: Ten male adult mongrel dogs were used, from which the three low premolars (P2, P3, P4) and the first molar were extracted. Three months after teeth extraction, two implant sites were bilaterally drilled, buccal bone dehiscences were created and four titanium implants were placed. Dehiscences were randomly assigned to the following groups: (1) PRP, (2) GBR, (3) PRP+GBR and (4) control. After 3 months, the animals were sacrificed and the implants and adjacent hard tissues were processed for undecalcified sections. Bone-to-implant contact (BIC), bone density within the limits of implant threads (BW), bone density (BD) and new bone area (BA) in a zone lateral to the implant corresponding to bone defects were obtained and measured. RESULTS: Intergroup analysis (two-way ANOVA -alpha=5%) demonstrated that when PRP was utilized,no differences were observed for all parameters (P>0.05). However, significant differences were observed for BIC and BW toward membrane-treated groups (P<0.05). CONCLUSION: Within the limits of this study, it was concluded that PRP does not exert additional effects on bone healing in bone defects created around dental implants and treated by GBR.     

Deproteinized bovine bone and biodegradable barrier membranes to support healing following immediate placement of transmucosal implants: a short-term controlled clinical trial

This 6-month clinical study evaluated the use of a porous bone mineral matrix xenograft (Bio-Oss) as an adjunct to a biodegradable barrier membrane (Bio-Gide) to support healing following the immediate placement of transmucosal implants into extraction sockets. Twenty adult patients scheduled for tooth replacement with dental implants were accepted for participation. Following implant placement into the extraction site, subjects were assigned to one of two treatment alternatives for the remaining bone defect around the implant: (1) Bio-Oss + Bio-Gide membrane (test); or (2) Bio-Gide membrane (control). The treatment outcome was evaluated after 6 months by the use of clinical and radiographic variables. The null hypothesis of no treatment group differences was tested by ANOVA. At 6 months, the radiographic bone level remained unchanged compared to baseline in the test and control groups. No differences were observed between test and control groups in terms of mean probing attachment level. At proximal sites, the soft tissue margin was located 2.6 mm more coronal than the shoulder of the implant in the test group, compared to 1.3 mm in the control group. The corresponding figures for the lingual aspect were 2.3 mm and 1.1 mm, respectively, and at buccal sites 2.1 mm and 0.9 mm, respectively. The use of deproteinized bovine bone mineral as a membrane support at immediately placed transmucosal implants may offer an advantage in areas with high esthetic demands in terms of soft tissue support.     

Alveolar bone formation at dental implant dehiscence defects following guided bone regeneration and xenogeneic freeze‐dried demineralized bone matrix

The present study evaluated rate and extent of alveolar bone formation in dental implant dehiscence defects following guided bone regeneration(GBR) and implantation of xenogeneic freeze‐dried demineralized bone matrix (xDBM). A total of 16 titanium plasma‐sprayed (TPS) and 16 hydroxyapatite‐coated (HA) titanium cylinder implants were inserted in 4 mongrel dogs following extraction of the mandibular premolar teeth. Four implant sites per jaw quadrant (2 TPS and 2 HA implant sites) were prepared into extraction sockets in each dog. Buccal alveolar bone was removed to create 3 x 5 mm dehiscence defects. Two jaw quadrants in separate animals received GBR, GBR+xDBM, xDBM (control), or gingival flap surgery alone (GFS; control). Thus, four conditions were available for each implant type (TPS or HA): GBR, GBR+xDBM; xDBM and GFS. The animals received fluorescent bone labels to allow observations of rate and extent of bone formation. Animals were sacrificed at 12 weeks postsurgery and block sections were harvested for histologic analysis. There were no apparent histologic differences between TPS and HA implant defects. GBR and GBR+xDBM resulted in almost complete bone closure of the dental implant dehiscence defect. Rate of bone formation appeared higher following GBR alone. Extent of bone formation appeared somewhat greater following GBR+xDBM; however, delayed. xDBM alone did not adequately resolve the bony defect. In conclusion, GBR results in rapid, clinically relevant bone closure of dental implant dehiscence defects. Adjunctive implantation of xDBM does not appear to significantly improve the healing response in the model used.     

Single stage surgery combining transmucosal implant placement with guided bone regeneration and bioresorbable materials

The aim of the present clinical study was to test whether peri-implant bone defects can successfully be filled with bone by applying bioresorbable materials for guided bone regeneration (GBR) procedures in conjunction with implants in the transmucosal healing position. Three women and 7 men ranging in age from 32 to 68 years (median 54.5) needed tooth replacement with dental implants. Eight to 14 weeks following careful tooth extraction, implants of the ITI Dental Implant System were placed at the extraction sites. At this time, all implants presented dehiscence defects of the alveolar bone partly exposing the rough titanium plasma sprayed (TPS) surfaces. GBR procedures were performed using deproteinized bovine bone mineral (Bio-Oss) as a membrane-supporting material and a bioresorbable collagen membrane (Bio-Gide) as a barrier. The membranes and the flaps were adjusted to fit around the necks of the implants, thus leaving the implants extending transmucosally into the oral cavity. Clinical measurements were taken at 6 sites around each implant (mesio-buccal, buccal, disto-buccal, disto-lingual, lingual, mesio-lingual) using a calibrated periodontal probe. These included: i) defect depth measured from the shoulder of the implant to the first bone-to-implant contact, ii) infrabony defect component measured from the bone crest to the first bone-to-implant contact, iii) defect width measured from the crest to the implant body in a direction perpendicular to the long axis of the implant. The Wilcoxon Matched Pairs Signed Rank Test was applied to detect differences over time. At baseline, the mean defect depth per patient amounted to 3.6 mm (Standard Deviation 1.6 mm, range 1.8-6.8 mm). The deepest extensions of the defects were located at the buccal aspects (mean 7.8 mm, SD 1.9 mm). At re-entry, the mean defect had decreased to 2.5 mm (SD 0.6 mm). This difference was statistically significant (P < 0.01). Initially, in 62% of sites the depth ranged from 0-3 mm, in 23% it ranged from 2-4 mm, and in 15% it amounted to more than 6 mm. Six to 7 months later, at re-entry, 95% of sites were 3 mm and less in depth and 5% ranged from 4-6 mm. Defect resolution, as assessed by the amount of coverage of the initially exposed rough implant surface, reached a mean value of 86% (SD 33%). One hundred percent resolution was accomplished at 8 out of 10 implants, 60% at one and 0% at another implant. The tissue at the latter implant showed signs of infection and inflammation during the healing phase. It is concluded that bioresorbable materials in GBR procedures at transmucosal implants can lead to successful bone regeneration into peri-implant defects.