Linear and volumetric gain after vertical bone augmentation in the posterior mandible using an autologous cortical tenting method

This study was performed to evaluate the linear and volumetric effects of a technique for reconstruction of the posterior atrophic mandible, including the final bone gain of the graft, by three-dimensional assessment. Thirteen individuals were recruited into the study and submitted to a total of 15 mandibular autogenous bone block surgeries. Cone beam computed tomography images were obtained at three different times. Bone graft length and thickness, and the volume, height, and width of the graft were measured. Data were compared statistically among the time points using the Friedman test, and cluster analysis was performed to identify the association between the study variables and the resorption rate (α = 0.05). Linear analysis of the width and height of the recipient area at the different time points revealed a statistically significant difference. The final average increase in height was 1.6 mm; all subjects showed an average volume gain of 3.412 mm³, and 77% of the subjects showed an average graft resorption of 0.688 mm³ construction of three-dimensional vertical defects of the posterior mandible resulted in good healing with minimal complications and minimal bone graft resorption, favouring vertical bone gain.     

Effects of EMD in combination with bone swaging and calcium phosphate bone cement on periodontal regeneration in one‐wall intrabony defects in dogs

Background and Objective: Although the application of EMD is a widely accepted periodontal‐regenerative therapy, its effects on noncontained intrabony defects are unpredictable because of the lack of a space‐making property. The combined use of EMD and autogenous bone grafts reportedly stimulates significant periodontal regeneration in intrabony defects. The aim of the present study was to evaluate the effects of EMD in combination with bone swaging (BS) and injectable calcium phosphate bone cement (CPC), which was placed into the spaces between the grafted swaged bone and the proximal host bone, on periodontal healing in one‐wall intrabony defects in dogs. Material and Methods: One‐wall intrabony defects (3 mm wide and 5 mm deep) were surgically created on the mesial and distal sides of the bilateral mandibular premolars in four dogs. The 16 defects were assigned to one of the following treatments: EMD only, BS only, EMD with BS (EMD + BS), or EMD with BS and CPC (EMD + BS + CPC). The animals were killed 8 wk after surgery for histologic evaluation. Results: The height of newly formed bone was significantly greater in the EMD + BS + CPC group (3.73 ± 0.30 mm) than in the BS‐only (2.74 ± 0.33 mm; p < 0.05) and EMD + BS (2.88 ± 0.98 mm; p < 0.05) groups. The area of newly formed bone was significantly larger in the EMD + BS + CPC group (5.68 ± 1.66 mm²) than in the EMD‐only (3.68 ± 0.33 mm²; p < 0.05), BS‐only (3.48 ± 1.26 mm²; p < 0.05) and EMD + BS (3.38 ± 1.37 mm²; p < 0.05) groups. The EMD‐only (4.63 ± 0.42 mm), EMD + BS (4.67 ± 0.30 mm) and EMD + BS + CPC (4.78 ± 0.54 mm) groups showed significantly greater cementum formation than did the BS‐only group (3.93 ± 0.56 mm; p < 0.05). Conclusion: These results indicate that treatment with EMD + BS + CPC promotes favorable periodontal healing in one‐wall intrabony defects in dogs.     

Alveolar ridge reconstruction with titanium mesh and autogenous particulate bone graft: computed tomography-based evaluations of augmented bone quality and quantity

Purpose: The purpose of this study was to evaluate the quality and quantity of augmented bone following alveolar ridge reconstruction with titanium mesh and autogenous particulate bone graft for implant placement in terms of the preoperative bone defect. Materials and Methods: Forty‐one patients (50 sites) rehabilitated between September 2000 and May 2009 with autogenous particulate intraoral bone or iliac cancellous bone marrow grafts and micro‐titanium meshes were enrolled. We classified the bone defects by means of shape as complex horizontal–vertical (HV), horizontal (H), and socket (S) types, and the augmented bone was evaluated based on preoperative computed tomographic data. The postsurgical complications were assessed during the healing period and after implant superstructure placement. Results: The bone defects were successfully augmented using the titanium mesh technique. The HV‐type defect was the most difficult to augment (mean horizontal gain, 3.7 ± 2.0 [SD] mm; mean vertical gain, 5.4 ± 3.4 [SD] mm). The mean horizontal gain with the H‐type defect was 3.9 ± 1.9 mm. The S‐type defect achieved the most efficient bone augmentation (mean horizontal gain, 5.7 ± 1.4 [SD] mm; mean vertical gain, 12.4 ± 3.1 [SD] mm). The major postsurgical complications were mesh exposure, infection, total or partial bone resorption, and temporary neurological disturbances. Implant failure was observed in one case. The HV‐type defect showed significantly higher bone resorption (p < .05) than the other defect types. Conclusions: Autogenous bone grafting with titanium mesh allows adequate vertical and horizontal alveolar bone reconstruction both quantitatively and qualitatively for implant placement. However, the clinical outcome of augmentation depends on the type of preoperative bone defect.     

Age‐related new bone formation following the use of cancellous bone‐block allografts for reconstruction of atrophic alveolar ridges

Background

An age‐related decrease in the number of osteogenic progenitor cells may compromise bone augmentation.

Purpose

Histomorphometrical assessment of age‐related new bone formation, following atrophic alveolar ridge reconstruction, using cancellous bone‐block allografts.

Material and methods

Ninety‐three consecutive patients (58 females and 35 males) were referred for implant‐supported restoration of 122 severe atrophic alveolar ridges. Alveolar ridge deficiency locations were classified as anterior maxilla (n = 58), posterior maxilla (n= 32), and posterior mandible (n = 32). A bony deficiency of at least 3 mm horizontally and up to 3 mm vertically according to computerized tomography (CT) in the posterior mandible and anterior maxilla, served as inclusion criteria. In the posterior maxilla, a residual alveolar ridge up to 4 mm vertically according to CT served as inclusion criteria. Augmentation was performed by the use of cancellous bone‐block allografts. Bone biopsies (9‐month posterior maxilla, 4 months anterior maxilla and posterior mandible) of young (≤40 years) versus older (>40 years) patients were histomorphometrically evaluated.

Results

In the posterior maxilla, no statistically significant histomorphometric differences were noted. While at the anterior maxilla and posterior mandible, statistically significant more newly formed bone was found in young versus older individuals, respectively (38.6% vs 19.8%, P = 0.04 and 69% vs 31%, P = .05).

Conclusion

New bone formation following residual alveolar ridge bone grafting is age‐related. Longer bone consolidation and healing time may be recommended for older individuals.     

Clinical efficacy of autogenous dentin grafts with guided bone regeneration for horizontal ridge augmentation: a prospective observational study

The aim of this study was to evaluate the efficacy of autogenous dentin grafts with guided bone regeneration (GBR) for horizontal ridge augmentation. Nineteen patients with dentition and bone defects in whom tooth/teeth extraction was indicated were recruited. Autogenous teeth were prepared, fixed on the buccal sides of the defects, and covered with bone powder and resorbable membranes before implantation. The horizontal bone mass at 0 mm (W1), 3 mm (W2), and 6 mm (W3) from the alveolar crest was recorded using cone beam computed tomography, before, immediately after, and 6 months after dentin grafting. All adverse effects were recorded. The implant stability quotient (ISQ) was measured 6 months after implantation. Twenty-eight implants were placed 6 months after dentin grafting. At this time point, the bone mass was 4.72 ± 0.72 mm (W1), 7.35 ± 1.57 mm (W2), and 8.96 ± 2.38 mm (W3), which was significantly different from that before the surgery (P < 0.05). The bone gain was 2.50 ± 0.72 mm (W1), 4.10 ± 1.42 mm (W2), and 4.56 ± 2.09 mm (W3). No soft tissue dehiscence or infection was observed. Overall, 26.3% of the patients experienced severe pain after dentin grafting. The ISQ was 78.31 ± 6.64 at 6 months after implantation. Autogenous tooth roots with GBR might be effective for horizontal ridge augmentation. This technique could be an alternative to augmentation using autogenous bone grafts.     

Efficacy of tissue engineered bone grafts containing mesenchymal stromal cells for cleft alveolar osteoplasty in a rat model

The development of sufficient tissue engineered bone grafts for alveolar cleft osteoplasty could reduce the necessity of autogenous bone grafts and its donor site morbidity. The aim of the study was to evaluate tissue engineered bone grafts in an artificially created bone defect.Bone grafts were created in vitro colonizing a synthetic hydroxyapatite–tricalciumphosphate scaffold (BONITmatrix^®) with either undifferentiated mesenchymal stromal cells (group 1) or osteogenic differentiated mesenchymal stromal cells (group 2). Cells were multiplied from bone marrow of donor rats. Unmodified scaffolds (group 3) and the tissue engineered bone grafts were inserted into artificial maxillary defects of 54 Lewis rats. In 18 animals the defects remained unfilled (control). After one, three and six weeks the rats were sacrificed. The defect was evaluated radiologically and histologically with regard to the remaining defect volume and diameter. Statistical analysis followed.The bone grafts led to a specific bone formation at the defect margin. No complete reunion of any defect was observed within the healing time. After six weeks, the remaining defect volume was 6.86 ± 3.21 mm³ (control), 4.08 ± 1.36 mm³ (group 1), 5.00 ± 0.84 mm³ (group 2) 5.50 ± 1.05 mm³ (group 3). The remaining defect diameter measured 2.63 ± 0.52 mm (control), 2.39 ± 0.23 mm (group 1), 2.53 ± 0.22 mm (group 2) and 2.70 ± 0.66 mm (group 3). In all experimental groups the defect volume and diameter decreased over time, which was significant for group 1 (p = 0.014), group 2 (p = 0.025) and group 3 (p = 0.048). The defect volume and width was significantly reduced for bone grafts containing undifferentiated cells compared to control (p = 0.035) or scaffolds only (p = 0.05).ConclusionTissue engineered bone grafts induce a pronounced bone formation in artificial bone defects compared to unfilled controls or scaffolds only.     

Osteoinductive potential of recombinant BMP-9 in bone defects of mice treated with antiresorptive agents

The aim of the present study was to investigate the effects of recombinant human (rh)BMP-9 on bone regenerative potential in a mouse model of antibody-mediated antiresorptive therapy (AMART). A monoclonal anti-murine receptor activator of nuclear factor-kappa B ligand (RANKL) antibody (mAb) was used to create an AMART model in mice. rhBMP-9 combined with collagen membrane was implanted in calvarial defects in mAb-treated mice. After 4 weeks, the bone formative potential in the defects was evaluated by micro-computed tomography and histological approaches. The groups implanted with rhBMP-9-containing collagen membranes demonstrated substantial osteopromotive potential, with significantly greater new bone volume (Sham + BMP-9 group; 0.86 ± 0.29 mm³ and mAb + BMP-9 group; 0.64 ± 0.16 mm³) than control PBS-membranes (Sham + PBS group; 0.44 ± 0.29 mm³ and mAb + PBS group; 0.24 ± 0.12 mm³) in both sham and mAb-treated mice. In line with in vivo study, bone marrow cells isolated from both sham and mAb-treated mice confirmed greater osteogenic potential upon stimulation with rhBMP-9 in vitro. These findings suggest for the first time that local rhBMP-9 administration might be a strategy to accelerate bone regeneration in the context of AMART.     

下颌正中管的锥形束CT三维重建

目的 通过锥形束CT(CBCT)扫描对下颌正中管的存在与否、走向及其与周围组织的三维关系进行评估及测量,为颏下区手术的安全提供保障.方法 对100例患者的CBCT图像进行三维重建并测量.测量项目包括Mandibular Icisive Canal(MIC)的存在与否,MIC垂直向和水平向直径,MIC在下颌管起始点,第一前磨牙对应点,尖牙对应点,切牙对应点至牙根尖、下颌骨颊侧壁、舌侧壁、下颌下缘以及牙槽嵴顶的垂直距离.结果 100例CBCT中百分百可见MIC.MIC与颊侧骨板和舌侧骨板平均距离分别为3.52±0.54 mm和5.37±0.25 mm,与下颌骨下缘、牙根尖和牙槽嵴顶的平均距离为10.44±0.61、10.57±0.76及20.21±0.83 mm.MIC到下颌骨下缘的距离男性为10.70±0.43 mm,女性为10.17±0.63 mm,P<0.05,差异具有统计学意义.结论 MIC在CBCT中检出率高且走向各异.     

Delayed immediate implants: alveolar bone chamzes durinrr the healing period

Delaying the placement of immediate fixtures by 6–8 weeks after extraction of the natural dentition allows for the elimination of associated infective processes, the achievement of maximum osteoblastic activity that theoretically could help the osseointegration process and complete wound covering that simplifies the placement of grafts or membranes. This study examines the healing associated with 21 fixtures in 14 patients. The fixtures were placed into sockets 6–8 weeks after tooth extraction without the use of barrier membranes or bone substitutes. Measurements were taken immediately prior to fixture placement and 3–6 months later at the abutment placement. Alveolar bone height, the remaining socket depth and diameter and the depth to which a 3.75 mm fixture could be inserted into the socket were measured. After fixture placement the vertical and horizontal measurements from the cover screw to the surrounding alveolar bone and the distance from the cover screw to the CEJ of the adjacent tooth were recorded. All fixtures were integrated at exposure with 1 failure during the follow-up period. The distance from the cover screw to the buccal plate decreased by a mean of 2.17 mm. There was an increase in the mean vertical bone height at all 4 surfaces. When horizontal defects were present, the mean vertical distance decreased from 2.5±0.37 mm to 0.36±0.64 mm. When horizontal defects were absent, the mean vertical distance decreased from 3.86±0.58 mm to 0.48±0.25 mm. There was also a marked decrease in the horizontal distance between the bone margin and the surface of the fixture from 1.6±l.73 mm 1 to 0.02±0.02 mm. These results indicate a strong tendency for the defects to fill-in in the horizontal plane and for bone growth to occur in the vertical plane to the height of the cover screw. In conclusion the delayed immediate placement of fixtures has a good short-term prognosis with bone regeneration occurring around the defect without the use of barrier membranes or bone substitutes.     

Outcomes of alveolar segmental ‘sandwich’ osteotomy with interpositional particulate allograft for severe vertical defects in the anterior maxilla and mandible

The purpose of this study was to report the outcomes of interpositional osteotomy with mineralized allograft in the treatment of alveolar vertical defects in preparation for implant placement. Thirteen defects (11 maxillary and two mandibular) were treated with osteotomy segments ranging in length from two to five missing teeth. The segments were positioned 5–7 mm coronally, with the gap space filled with allograft and then fixated with titanium hardware. Vertical bone augmentation was analyzed by superimposing pre- and post-surgical cone beam computed tomography images and stratified based on the length and number of missing teeth in each edentulous segment. The mean vertical bone gain was 3.7 ± 1.6 mm in the area of greatest vertical defect and the mean length of the transport segment was 20.5 ± 8.1 mm. These segments represented two-, three-, four-, or five-tooth edentulous sites; the mean vertical bone gain for these segments was 1.7 ± 0.5 mm, 3.8 ± 1.0 mm, 4.6 ± 0.9 mm, and 6.7 ± 0.0 mm, respectively. Stability of vertical height gain was found to be directly proportional to the span length of the osteotomy segment, with the largest five-tooth segment achieving the greatest gain. Vertical bone gain in two-tooth segments was minimal, indicating a moderate amount of resorption.     

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.     

Rosuvastatin 1.2 mg In Situ Gel Combined With 1:1 Mixture of Autologous Platelet‐Rich Fibrin and Porous Hydroxyapatite Bone Graft in Surgical Treatment of Mandibular Class II Furcation Defects: A Randomized Clinical Control Trial

Background: A wide range of regenerative materials have been tried and tested in the treatment of furcation defects. Rosuvastatin (RSV) is a new synthetic, second‐generation, sulfur‐containing, hydrophilic statin with potent anti‐inflammatory and osseodifferentiation mechanisms of action. Platelet‐rich fibrin (PRF) is a platelet concentrate having sustained release of various growth factors with regenerative potential to treat periodontal defects. Porous hydroxyapatite (HA) bone grafting material has a clinically satisfactory response when used to fill periodontal intrabony defects. This double‐masked randomized study is designed to evaluate the potency of a combination of 1.2 mg RSV in situ gel with a 1:1 mixture of autologous PRF and HA bone graft in the surgical treatment of mandibular Class II furcation defects compared with autologous PRF and HA bone graft placed after open‐flap debridement (OFD). Methods: One hundred five mandibular furcation defects were treated with OFD + placebo gel (group 1), PRF + HA with OFD (group 2), or 1.2 mg RSV gel + PRF + HA with OFD (group 3). Clinical and radiologic parameters (i.e., probing depth [PD], relative vertical and relative horizontal clinical attachment level [rvCAL and rhCAL], intrabony defect depth, and percentage of defect fill) were recorded at baseline and 9 months postoperatively. Results: Mean PD reduction was greater in group 2 (3.68 ± 1.07 mm) and group 3 (4.62 ± 1.03 mm) than group 1 (2.11 ± 1.25 mm), and mean rvCAL and rhCAL gain were greater in group 2 (3.31 ± 0.52 and 2.97 ± 0.56 mm, respectively) and group 3 (4.17 ± 0.70 and 4.05 ± 0.76 mm) compared with group 1 (1.82 ± 0.78 and 1.62 ± 0.64 mm). A significantly greater percentage of mean bone fill was found in group 2 (54.69% ± 1.93%) and group 3 (61.94% ± 3.54%) compared with group 1 (10.09% ± 4.28%). Conclusions: Treatment of furcation defects with 1.2 mg RSV in situ gel combined with autologous PRF and porous HA bone graft results in significant improvements of clinical and radiographic parameters compared with OFD alone. These results imply that the combination of RSV, PRF, and HA has synergistic effects, explaining their role as a regenerative material in the treatment of furcation defects.     

Influence of two barrier membranes on staged guided bone regeneration and osseointegration of titanium implants in dogs: part 1. Augmentation using bone graft substitutes and autogenous bone

Objectives: To assess the influence of two barrier membranes and two bone graft substitutes mixed with autogenous bone (AB) on staged guided bone regeneration and osseointegration of titanium implants in dogs. Materials and methods: Four saddle‐type defects each were prepared in the upper jaw of six fox hounds and randomly filled with a natural bone mineral (NBM)+AB and a biphasic calcium phosphate (SBC)+AB and allocated to either an in situ gelling polyethylene glycol (PEG) or a collagen membrane (CM). At 8 weeks, modSLA titanium implants were inserted and left to heal in a submerged position. At 8+2 weeks, dissected blocks were processed for histomorphometrical analysis (e.g., treated area [TA], bone‐to‐implant contact [BIC]). Results: The mean TA values (mm²) and BIC values (%) tended to be higher in the PEG groups(TA: NBM+AB [10.4 ± 2.5]; SBC+AB [10.4 ± 5.8]/BIC: NBM+AB [86.4 ± 20.1]; SBC+AB [80.1 ± 21.5]) when compared with the corresponding CM groups (TA: NBM+AB [9.7 ± 4.8]; SBC+AB [7.8 ± 4.3]/BIC: NBM+AB [71.3 ± 20.8]; SBC+AB [72.4 ± 20.3]). A significant difference was observed for the mean TA values in the SBC+AB groups. Conclusion: It was concluded that all augmentation procedures investigated supported bone regeneration and staged osseointegration of modSLA titanium implants. However, the application of PEG may be associated with increased TA values. To cite this article:
Schwarz F, Mihatovic I, Golubovic V, Hegewald A, Becker J. Influence of two barrier membranes on staged guided bone regeneration and osseointegration of titanium implants in dogs: part 1. Augmentation using bone graft substitutes and autogenous bone.
Clin. Oral Impl. Res. 23 , 2012; 83–89.
doi: 10.1111/j.1600‐0501.2011.02187.x     

Cancellous Bone Block Allografts for the Augmentation of the Anterior Atrophic Maxilla

Background: Pre‐implant augmentative surgery is a prerequisite in many cases in the anterior maxilla to achieve a stable, long‐term esthetic final result. Purpose: The aim of the present study was to evaluate the outcome of ridge augmentation with cancellous freeze‐dried block bone allografts in the anterior atrophic maxilla followed by placement of dental implants. Materials and Methods: Thirty‐one consecutive patients were included in the study. A bony deficiency of at least 3 mm horizontally and up to 3 mm vertically according to computerized tomography (CT) served as inclusion criteria. Sixty‐three implants were inserted after a healing period of 6 months. Nineteen of sixty‐three implants were immediately restored. Bone measurements were taken prior to bone augmentation, during implant placement, and at second‐stage surgery. Results: Forty‐six cancellous allogeneic bone blocks were used. The mean follow‐up was 34 ± 16 months. Mean bone gain was 5 ± 0.5 mm horizontally, and 2 ± 0.5 mm vertically. Mean buccal bone resorption was 0.5 ± 0.5 mm at implant placement, and 0.2 ± 0.2 mm at second‐stage surgery. Mean bone thickness buccal to the implant neck was 2.5 ± 0.5 mm at implant placement, and 2.3 ± 0.2 mm at second‐stage surgery. There was no evidence of vertical bone loss between implant placement and second‐stage surgery. Block and implant survival rates were 95.6 and 98%, respectively. All patients received a fixed implant‐supported prosthesis. Conclusion: Cancellous block allografts appear to hold promise for grafting the anterior atrophic maxilla.     

RhBMP-2/alphaBSM induces significant vertical alveolar ridge augmentation and dental implant osseointegration

Background: Recombinant human bone morphogenetic protein 2 (rhBMP‐2) in a carrier has been shown to induce significant bone formation. Several candidate carriers, however, lack structural integrity to offset compressive forces that may compromise rhBMP‐2 bone induction, in particular, for challenging onlay indications such as alveolar ridge augmentation. Purpose: The objective of this study was to evaluate rhBMP‐2 in a calcium‐phosphate cement carrier, αBSM, for vertical alveolar ridge augmentation and immediate dental implant Osseointegration. Materials and Methods: Six adult Hound Labrador mongrels with 5 mm critical size supra‐alveolar peri‐implant defects were used. Three animals received rhBMP‐2/αBSM (rhBMP‐2 at 0.40 and 0.75 mg/mL) in contralateral jaw quadrants (total implant volume/defect ～ 1.5 mL). Three animals received αBSM without rhBMP‐2 (control group). The animals were euthanized at 16 weeks post surgery, and block biopsies were processed for histologie and histometric analysis. Results: rhBMP‐2/αBSM induced substantial augmentation of the alveolar ridge. Control sites exhibited limited new bone formation. Vertical bone augmentation averaged (SD) 4.9 ± 1.0 mm (rhBMP‐2 at 0.40 mg/mL), 5.3 ± 0.3 mm (rhBMP‐2 at 0.75 mg/mL), and 0.4 ± 0.4 mm (control); new bone area 8.5 ± 4.2 mm ², 9.0 ± 1.9 mm ², and 0.5 ± 0.4 mm ²; new bone density 55.1 ± 6.4%, 61.1 ± 6.0%, and 67.7 ± 9.5%; and new bone‐implant contact 26.9 ± 17.5%, 28.5 ± 1.4%, and 24.6 ± 16.1%, respectively. Residual αBSM comprised 1% of the new bone. Bone density for the contiguous resident bone ranged from 65 to 71%, and bone‐implant contact ranged from 49 to 64%. Conclusions: Surgical implantation of rhBMP‐2/αBSM appears an effective protocol for vertical alveolar ridge augmentation procedures and immediate dental implant Osseointegration and for onlay indications of lesser complexity.     

Clinical evaluation of particulate allogeneic with and without autogenous bone grafts and resorbable collagen membranes for bone augmentation of atrophic alveolar ridges

Objectives: The evaluate the clinical outcome of bone augmentation with the use of particulate mineralized freeze‐dried bone allograft (FDBA) with or without the addition of autogeneous bone chips, applied in a bi‐layered (BL) technique, covered by a resorbable cross‐linked collagen membrane. Material and methods: Fifty patients presenting with a vertical and/or lateral ridge deficiency of at least 3 mm were included: Group FDBA, N=27 patients, particulate FDBA was the only graft; and Group BL, N=23 patients, a BL bone grafting procedure where autogenous bone chips were the inner layer and FDBA the outer. Bone graft was covered with a ribose cross‐linked collagen barrier membrane. Ridge dimensions were clinically or radiographically (computerized tomography scan) measured at the time of the bone augmentation procedure and at implant placement or uncovering and the maximum linear vertical or horizontal calcified tissue gain was calculated. Statistical analysis consisted of linear regression analysis, with maximum bone gain being the dependent variable. Results: In the FDBA group, mean vertical bone gain was 3.47 mm (SD 1.25) and the horizontal, 5 mm (SD 1.28), while in the BL values were 3.5 mm (SD 1.2) and 3.6 mm (SD 1.72), respectively. Addition of autogenous bone does not appear to statistically significantly enhance the results. Spontaneous membrane exposure occurred in 24% of the cases and was the only variant that significantly influenced results (P<0.001). Conclusions: Large vertical and/or horizontal ridge deficiencies may be treated with FDBA and ribose cross‐linked collagen barrier membranes with good clinical outcome. No added effect of the application of a layer of autogenous bone in these bone augmentation procedures could be demonstrated. Spontaneous membrane exposure was the only parameter to affect the degree of new calcified tissue formation. To cite this article:
Beitlitum I, Artzi Z, Nemcovsky CE.
Clinical evaluation of particulate allogeneic with and without autogenous bone grafts and resorbable collagen membranes for bone augmentation of atrophic alveolar ridges.
Clin. Oral Impl. Res. 21 , 2010; 1242–1250.
doi: 10.1111/j.1600‐0501.2010.01936.x     

Two-stage reconstruction of the severely deficient alveolar ridge: bone graft followed by alveolar distraction osteogenesis

Distraction osteogenesis for the augmentation of severe alveolar bone deficiency has gained popularity during the past two decades. In cases where the vertical bone height is not sufficient to create a stable transport segment, performing alveolar distraction osteogenesis (ADO) is not possible. In these severe cases, a two-stage treatment protocol is suggested: onlay bone grafting followed by ADO. An iliac crest onlay bone graft followed by ADO was performed in 13 patients: seven in the mandible and six in the maxilla. Following ADO, endosseous implants and prosthetic restorations were placed. In all cases, the onlay bone graft resulted in inadequate height for implant placement, but allowed ADO to be performed. ADO was performed to a mean total vertical augmentation of 13.7 mm. Fifty-two endosseous implants were placed. During a mean follow-up of 4.85 years, two implants failed, both during the first 6 months; the survival rate was 96.15%. In severe cases lacking the required bone for ADO, using an onlay bone graft as a first stage treatment increases the bone height thus allowing ADO to be performed. This article describes a safe and stable two-stage treatment modality for severely atrophic cases, resulting in sufficient bone for implant placement and correction of the inter-maxillary vertical relationship.     

Influence of two barrier membranes on staged guided bone regeneration and osseointegration of titanium implants in dogs. Part 2: augmentation using bone graft substitutes

Objectives: To assess the influence of two barrier membranes and two bone graft substitutes on staged guided bone regeneration and osseointegration of titanium implants in dogs. Materials and methods: Saddle‐type defects were prepared in the lower jaws of 6 fox hounds and randomly filled with a natural bone mineral (NBM) and a biphasic calcium phosphate (SBC) and allocated to either an in situ gelling polyethylene glycol (PEG) or a collagen membrane (CM). At 8 weeks, modSLA titanium implants were inserted and left to heal in a submerged position. At 8+2 weeks, respectively, dissected blocks were processed for histomorphometrical analysis (e.g., mineralized tissue [MT], bone‐to‐implant contact [BIC]). Results: The mean MT values (mm²) and BIC values (%) tended to be higher in the PEG groups (MT: NBM [3.4±1.7]; SBC [4.2±2]/BIC: NBM [67.7±16.9]; SBC [66.9±17.8]) when compared with the corresponding CM groups (MT: NBM [2.5±0.8]; SBC [2.3±1.6]/BIC: NBM [54.1±22.6]; SBC [61±8.7]). These differences, however, did not reach statistical significance. Conclusion: It was concluded that all augmentation procedures investigated supported bone regeneration and staged osseointegration of modSLA titanium implants. To cite this article :
Mihatovic I, Becker J, Golubovic V, Hegewald A, Schwarz F. Influence of two barrier membranes on staged guided bone regeneration and osseointegration of titanium implants in dogs. Part 2: augmentation using bone graft substitutes.
Clin Oral Impl Res. 23 , 2012; 308–315.
doi: 10.1111/j.1600‐0501.2011.02238.x     

Efficacy of Using PDGF and Xenograft With or Without Collagen Membrane for Bone Regeneration Around Immediate Implants With Induced Dehiscence‐Type Defects: A Microcomputed Tomographic Study in Dogs

Background: Use of collagen membrane (CM) with xenograft and recombinant human platelet‐derived growth factor (rhPDGF) in guided bone regeneration (GBR) is debatable. The aim of this microcomputed tomographic experiment was to assess the efficacy of using PDGF and xenograft (with or without CM) for GBR around immediate implants with dehiscence defects. Methods: Ten beagle dogs underwent atraumatic bilateral second and fourth premolar extractions from both arches. A standardized dehiscence defect (6 × 3 mm) was created on the buccal bone and immediate implants were placed in distal sockets in each site. Animals were randomly divided into three groups: 1) group 1, xenograft with rhPDGF was placed and covered with CM; 2) group 2, xenograft with rhPDGF was placed over the defects; and 3) group 3, four immediate implants were associated with dehiscence (controls). After 16 weeks, animals were sacrificed and jaw segments were assessed for buccal bone thickness (BBT), buccal bone volume (BBV), vertical bone height (VBH), and bone‐to‐implant contact (BIC) using microcomputed tomography. Results: BBT was higher in group 2 (1.533 ± 0.89 mm) than group 1 (0.745 ± 0.322 mm) (P <0.001) and group 3 (0.257 ± 0.232 mm) (P <0.05). BBV was higher in group 2 (67.87 ± 19.83 mm³) than group 1 (42.47 ± 6.78 mm³) (P <0.05) and group 3 (19.12 ± 4.06 mm³) (P <0.001). VBH was higher in group 2 (6.36 ± 1.37 mm) than group 3 (0.00 ± 0.00 mm) (P <0.001). VBH was higher in group 1 (3.91 ± 2.68 mm) than group 3 (0.00 ± 0.00 mm) (P <0.05). BIC was higher in group 2 (67.25% ± 13.42%) than group 1 (36.25% ± 12.78%) (P <0.05) and group 3 (30.25% ± 7.27%) (P <0.01). Conclusion: GBR around immediate implants with dehiscence defects using PDGF and xenograft alone resulted in higher BBT, BBV, VBH, and BIC than when performed in combination with CM.     

Microcomputed Tomographic Analysis of the Alveolar Ridge Alteration around Extraction Sites with and without Immediate Implants Placement: In Vivo Study

Background: The aim was to assess the alveolar ridge alteration around extraction sites with and without immediate implants according to extraction socket classification (ESC) using microcomputed tomography (micro‐CT). Material and Methods: Ten beagle dogs (mean age and weight: 24 ± 0.83 months and 13.8 ± 0.49 kg, respectively) were randomly divided into three groups according to the ESC. In Group 1 (ESC‐I), bilateral first and third premolars were extracted and replaced with immediate implants. In Group 2 (ESC‐II), two adjacent premolars were extracted with one immediate implant placement in the mesial socket in the maxilla and in the distal socket in the mandible. In Group 3 (ESC‐III), three adjacent teeth were extracted and an immediate implant was placed in the central socket. Primary closure was achieved using resorbable sutures. Buccal sites with dehiscence defects were excluded. After 4 months, subjects were sacrificed and alveolar ridge widths were measured at 1 mm interval in axial and sagittal views, using micro‐CT in sites with and without immediate implants. Results: In sites without immediate implant placement, alveolar ridge width was significantly higher in Group 1(6.1 ± 1.35 mm) than Group 3 (4.14 ± 1.53 mm) (p < .05). In sites with immediate implant placement, the alveolar ridge width was higher among sites in Group 1 (6.4 ± 3.8 mm) than Group 2 (4.8 ± 0.46 mm) (p < .05) and Group 3 (5.02 ± 0.84 mm) (p < .05). Overall, between each corresponding group in both sites with and without immediate implant placement at 1 mm thickness, there was no significant difference in the alveolar ridge widths. Conclusion: With the exception of Group 1 (ESC‐I), immediate implant placement did not prevent or minimize bone remodeling in extraction sites according to ESC.