Clinical study of guided bone regeneration and/or bone grafts in the treatment of ligature-induced peri-implantitis defects in dogs.

This study evaluated, by clinical analysis, the hard tissue response following treatment of ligature-induced peri-implantitis defects in 5 dogs. The mandibular premolars were removed from both sides of the jaw. After 3 months of healing, two titanium implants were placed on each side of the mandible. Following abutment connection, 3 months later, experimental peri-implantitis was induced by the placement of cotton ligatures in a submarginal position. Ligatures and abutments were removed after one month and the bony defects were randomly assigned to one of the following treatments: debridement (DE), debridement plus guided bone regeneration (GBR), debridement plus mineralized bone graft (BG) and debridement plus guided bone regeneration associated with mineralized bone graft (GBR + BG). The peri-implant bone defects were clinically measured before and 5 months post-treatment. Results showed a higher percentage of vertical bone fill for GBR + BG (27.77 +/- 14.07) followed by GBR (21.78 +/- 16.19), BG (21.26 +/- 6.87), DE (14.03 +/- 5.6). However, there were no statistically significant differences between any of the treatments proposed (one way repeated measures analysis of variance, P = 0.265).     

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.     

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.     

Effect of autogenous harvest site location on the outcome of ridge augmentation for implant dehiscences

Treatment planning for the placement of an implant in a site with a thin crestal ridge should address the probability that a buccal dehiscence will result. The aim of the present investigation was to perform guided bone regeneration (GBR) around implants with buccal dehiscences and evaluate the outcomes of using autogenous bone grafts harvested from three different intraoral sites. Forty-six Osseotite implants, 4 mm in diameter, were placed in thin crestal ridges, resulting in an uncovered implant surface from the buccal aspect. The lengths of the buccal dehiscences ranged from 3 to 7 mm as measured from the implant cervix to the most apical extent of the uncovered threads. A standard GBR technique was carried out to augment the bone defect around the buccal implant surface immediately after implant placement. The cases were divided into three groups according to receipt of an autogenous bone graft from the ramus, tuberosity, or mandibular symphysis. In all cases, e-PTFE membranes were used to cover the grafted areas. Grafted sites were exposed after 6 months, membranes were removed, and residual distance between the implant cervix and most uncovered thread was recorded. All grafting materials were able to produce a certain degree of bone regeneration. In terms of bone change level, the three groups were not equal. The mandibular symphysis group exhibited the highest mean bone growth level, followed by the ramus group. The tuberosity produced the poorest result. Mandibular and ramus autogenous bone grafts represent the best choice in materials for GBR procedures around implants, while tuberosity bone grafts can be used as an alternative.     

Evaluation of guided bone regeneration and/or bone grafts in the treatment of ligature-induced peri-implantitis defects: a morphometric study in dogs

The goal of this study was to evaluate, morphometrically, hard-tissue healing following the treatment of ligature-induced peri-implantitis defects in dogs and guided bone regeneration and/or bone grafts. Five dogs were used, and the mandibular premolars were removed. Three months later, two titanium implants were installed on each side of the mandible, and after another 3 months, abutment connection was performed. Following abutment connection, experimental periimplantitis was induced by placing cotton ligatures in a submarginal position. Ligatures and abutments were removed after 1 month and the bony defects were randomly assigned to one of the following treatments: debridement (DE), debridement plus guided bone regeneration (GBR), debridement plus mineralized bone graft (BG), and debridement plus guided bone regeneration associated with mineralized bone graft (GBR/BG). The dogs were euthanatized after 5 months. Morphometric analysis did not reveal significant differences among the treatments neither with respect to the percentage of bone to implant contact (p = 0.996) nor to the bone area (p = 0.946) within the limits of the threads of the implant. Within the limits of this investigation, there is insufficient evidence to indicate that any of the treatments presented an improved response in dealing with bony defects resulting from peri-implantitis.     

Clinical study of guided bone regeneration with resorbable polylactide-co-glycolide acid membrane

The guided bone regeneration (GBR) technique is often applied to provide sufficient bone for ideal implant placement. The objective of this study was to evaluate whether GC membrane^®, which has already been used for guided tissue regeneration (GTR), can also be available for GBR. Twenty-three implants in 18 patients were evaluated in the study. All patients underwent implant placement with GBR using GC membrane^®. Cone-beam computed tomography was performed at 13–30 weeks after surgery and the amount of augmented bone was assessed. The implant stability quotient (ISQ) was measured at the second operation to evaluate implant stability. Although wound dehiscence was observed at 4 of 23 regions (17.4%), all wounds closed quickly without any events by additional antibiotic administration. GBR-induced bone augmentation of 0.70–2.56 mm horizontally and 0–6.82 mm vertically. Only 0.18 mm of bone recession was observed at 16–24 months after implant placement. GBR with GC membrane^® induced sufficient bone augmentation, leading to successful implant treatment. The present results suggest that GC membrane^® is available not only for GTR, but also for GBR.     

Enamel matrix derivative and bone healing after guided bone regeneration in dehiscence-type defects around implants. A histomorphometric study in dogs

BACKGROUND: The goal of this investigation was to histometrically evaluate the effect of enamel matrix derivative (EMD) on bone healing after guided bone regeneration (GBR) in dehiscence-type osseous defects around dental implants; i.e., in the absence of periodontal ligament cells. METHODS: Six mongrel dogs were used. The second, third, and fourth mandibular premolars (p2, p3, and p4) and first molars (ml) were extracted. After 3 months, 2 implant osteotomies were prepared in each side of the mandible, dehiscence-type defects were created on the buccal aspect of each implant osteotomy (3.5 mm x 5.0 mm), and titanium implants were placed (3.75 mm x 8.5 mm). The surgically-created defects were randomly assigned to one of the treatments: EMD, GBR, EMD+GBR, or control. After 2 months, 4 additional defects were created and treated. The animals were sacrificed 3 months after the placement of the first implants, thus allowing the healing periods of 1 and 3 months. Undecalcified sections were obtained for the histometric evaluation including the percentage of bone-to-implant contact and new bone area on the implant threads related to the defect. RESULTS: No statistically significant differences were observed among the groups in the evaluated parameters after 1 month of healing. After 3 months, no statistically significant differences were observed among the groups for the percentage of bone-to-implant contact. The values for the new bone area were: 55.5+/-11.8, 53.8+/-16.3, 62.1+/-18.4, and 36.9+/-25.1 for EMD, GBR, EMD+GBR, and control, respectively. The difference between EMD+GBR and control was statistically significant (P <0.05). CONCLUSIONS: Within the limits of this study, it can be concluded that EMD may positively influence bone healing after GBR around titanium implants. EMD alone, however, had no statistically significant effect.     

Guided bone regeneration for dehiscence and fenestration defects on implants using an absorbable polymer barrier

BACKGROUND: Guided bone regeneration (GBR) using a non-absorbable barrier has provided clinicians the ability to place implants in sites compromised by insufficient bone, including immediate extraction sites. Recent evidence suggests that successful GBR outcomes may be possible using bioabsorbable polymer barriers. METHODS: This report presents a case series of 9 patients with 8 fenestration and 3 dehiscence defects on implants consecutively treated with GBR. A bioabsorbable polymer barrier of poly(DL-lactide) was used in conjunction with a composite graft of freeze-dried bone allograft (FDBA)/demineralized freeze-dried bone allograft (DFDBA) mixed in a ratio of 1:1. Second-stage surgeries were performed at 4 to 8.5 months (5. 7 months average) post-placement. Biopsy material from 2 sites was obtained while exposing the implant for healing abutment connection. RESULTS: Ten of the 11 defects (90.9%) achieved complete coverage of the osseous defects. Histologic evaluations revealed the formation of viable bone, frequently in close amalgamation with residual graft particles. CONCLUSION: These case reports suggest that a poly(DL-lactide) polymer can be used as a physical barrier with a composite bone replacement graft to achieve successful GBR results of dehiscence/fenestration defects when placing implants.     

Alveolar distraction osteogenesis vs. vertical guided bone regeneration for the correction of vertically deficient edentulous ridges: a 1-3-year prospective study on humans

The purpose of this prospective study was to compare vertical guided bone regeneration (GBR) and vertical distraction osteogenesis (DO) for their ability in correcting vertically deficient alveolar ridges and their ability in maintaining over time the vertical bone gain obtained before and after implant placement. Eleven patients (group 1) were treated by means of vertical GBR with autogenous bone and e-PTFE membranes, while 10 patients (group 2) were treated by means of DO. In group 1, six patients received implants at the time of GBR (subgroup 1A), while five patients had implants placed at the time of membrane removal (subgroup 1B). In group 2, implants were placed at the time of distraction device removal. A total of 25 implants were placed in group 1 and 34 implants were placed in group 2 patients. Three to 5 months after implant placement, patients were rehabilitated with implant-borne dental prostheses. The following parameters were evaluated: (a) bone resorption of the regenerated ridges before and after implant placement; (b) peri-implant clinical parameters 1, 2, and 3 years after prosthetic loading of implants; (c) survival and success rates of implants. Bone resorption values before and after implant placement were significantly higher in group 1. The results suggested that both techniques may improve the deficit of vertically resorbed edentulous ridges, although distraction osteogenesis seems to be more predictable as far as the long-term prognosis of vertical bone gain is concerned. Implant survival rates as well as peri-implant clinical parameters do not differ significantly between the two groups, whereas the success rate of implants placed in group 2 patients was higher than that obtained in group 1 patients.     

Clinical outcomes of vertical bone augmentation to enable dental implant placement: a systematic review

Background: This review addressed the focused question of what is the predictability of vertical ridge augmentation techniques for patients, who were diagnosed with insufficient alveolar bone volume for the placement of dental implants.
Material and Methods: A systematic online review of three main databases was performed between 1966 and 1 November 2007. Four groups of vertical bone augmentation techniques have been identified and evaluated: (1) guided bone regeneration, (2) distraction osteogenesis, (3) onlay bone grafting, and (4) an array of different techniques. Data extraction was based on the following outcomes: (a) success and failure rate of the procedure (vertical bone gain/loss), (b) complication rate of the procedure, and (c) implant survival, success and failure rate.
Results: The initial search identified 189 papers from the electronic database. The review produced seven papers for GBR, 13 reporting distraction osteogenesis, five for onlay bone grafting and three describing different techniques.
Conclusions: For the concept of vertical ridge augmentation to enable dental implant placement, there are clinical and histological data supporting its potential use. Given the confined number of investigators using these techniques and the low number of patient treatments reported in the literature, the generalizability of this approach is limited at this time.     

Alveolar ridge and sinus augmentation utilizing platelet-rich plasma in combination with freeze-dried bone allograft: case series

BACKGROUND: Alveolar bone regeneration is frequently necessary prior to placement of implants. Efforts to improve wound healing have focused on factors that may enhance bone formation following guided bone regeneration (GBR) techniques alone or in combination with bone replacement graft materials. Recent reports suggest that platelet-rich plasma (PRP), presumably high in levels of peptide growth factors, may enhance the formation of new bone when used in combination with autogenous graft material. METHODS: In this report, the clinical and radiographic results are presented on 15 consecutively treated patients using autologous PRP in combination with freeze-dried bone allograft (FDBA) for sinus elevation and/or ridge augmentation. FDBA and PRP (0.5 g/2cc PRP) were mixed and placed as a composite graft material. A gel formed by mixing autologous thrombin-rich plasma with PRP (1:4 ratio) was used to cover the graft material. Core biopsies of grafted areas were obtained in several patients as part of implant site preparation and were evaluated histologically to determine site maturation. RESULTS: Of 36 implant fixtures, 32 (89%) were considered clinically successful demonstrating complete bone coverage of the implant, no mobility, and a normal radiographic appearance at the time of re-entry and 12 months post-implant exposure. Four implants were removed due to mobility at the time of surgical exposure. Histologic evaluation of biopsy specimens revealed numerous areas of osteoid and bone formation around FDBA particles, with no evidence of inflammatory cell infiltrate. CONCLUSIONS: These clinical and histological findings suggest that ridge augmentation and sinus grafting with FDBA in combination with PRP provide a viable therapeutic alternative for implant placements. Future studies are necessary to determine whether PRP enhances new bone formation or maturation with bone replacement allografts.     

2种修复膜材料用于牙种植引导骨再生的临床效果比较

目的：比较2种修复膜材料用于牙种植引导骨再生的临床效果。方法：选择上海市静安区牙病防治所2017年9月—2018年9月行牙种植引导骨再生治疗的患者139例,按随机表法分为对照组（68例）和试验组（71例）,对照组应用博特医用胶原修复膜引导骨再生,试验组应用海奥口腔修复膜引导骨再生,术后6个月随访记录修复情况,分别比较2组修复成功率和并发症发生率,并评价成骨厚度和高度、植骨厚度和高度,以及水平和垂直骨生长情况。采用SPSS 20.0软件包对数据进行统计学分析。结果：术后6个月,对照组修复成功率为85.29%（58/68）,试验组为95.77%（68/71）,差异有统计学意义(P<0.05);2组植骨厚度和植骨高度无显著差异(P>0.05),试验组成骨厚度、成骨高度、水平骨生长和垂直骨生长均显著高于对照组(P<0.05);对照组并发症发生率为25.00%,显著高于试验组的12.67%(P<0.05)。结论：海奥口腔修复膜引导骨再生的修复成功率优于博特医用胶原修复膜,可更好促进骨和植骨生长,疗效显著,安全性更高,更适合用于牙种植引导骨再生。     

Harvesting bone in the recipient sites for ridge augmentation

A modified ridge augmentation technique is introduced for augmenting deficient alveolar ridges in preparation for endosseous implant placement. The technique is based on the principles for guided bone regeneration, in which a created space is kept isolated from the surrounding soft tissues by a resorbable membrane with an excellent extended resorption profile, thus permitting the accrual of bone-formative elements into the graft site. The absorbable membrane is propped up by an autogenous mixture of native corticocancellous bone cores taken in the graft site and reduced to smaller particle sizes and osseous coagulum collected in bone traps and with a special bone scraper. The major advantage of this technique is that all the autogenous bone graft material is obtained from the actual graft site, avoiding second remote intra- or extraoral surgical sites and attendant morbidities. Ridges augmented with this technique permit optimal endosseous implant placement.     

Diagnosis and treatment of extraction sockets in preparation for implant placement: report of three cases

This article addresses diagnostic parameters that should be assessed in the treatment of extraction sockets with dental implant placement by presenting three case reports that emphasize the relevance of the amount of remaining bone walls. Diagnosis was based on the analysis of clinical and radiographic parameters (e.g.: bone defect morphology, remaining bone volume, presence of infections on the receptor site). Case 1 presents a 5-wall defect in the maxillary right central incisor region with severe root resorption, which was treated with immediate implant placement. Cases 2 and 3 present, respectively, two- and three-wall bone defects that did not have indication for immediate implants. These cases were first submitted to a guided bone regeneration (GBR) procedure with bone graft biomaterial and membrane barriers, and the implants were installed in a second surgical procedure. The analysis of the preoperative periodontal condition of the adjacent teeth and bone defect morphology is extremely important because these factors determine the choice between immediate implant or GBR treatment followed by implant installation in a subsequent intervention.     

美学区种植同期应用异种骨行引导骨再生术后愈合期间唇侧骨改建的临床研究

目的: 研究美学区种植同期应用异种骨行引导骨再生（GBR）术后愈合期间的唇侧骨改建。方法: 纳入2015年9月—2016年4月在上海交通大学医学院附属第九人民医院口腔种植科行GBR同期种植体植入的上前牙23例。术前、手术当天及二期手术阶段拍摄锥形束CT（CBCT）,记录牙龈厚度（>2 mm或≤2 mm）、骨质分类及使用的屏障膜。利用iCAT Vision数字化软件对种植体颈部肩台下2 mm（C）、体部中点（M）及根尖处（A）唇侧骨板进行测量,测量线与种植体长轴垂直。将纵切线向近中及远中各移动1 mm,得到新的纵切面,以同样方法测量唇侧骨板厚度并记录数值。在术前CBCT上测量牙槽嵴形态特征,记录牙槽嵴高度、倒凹深度及牙槽嵴宽度。采用SPSS 21.0软件包对数据进行统计学分析。结果: 种植体肩台下2 mm、体部中点及根尖处的平均骨吸收值分别为（0.70±0.59）mm、（0.85±0.72）mm和（0.55±0.51）mm,吸收率分别为23.07%、18.53%和12.97%。与植骨吸收相关的自变量中,相关分析表明,倒凹深度和年龄与植骨吸收量显著相关（P<0.05）;将所有变量纳入多重线性回归并行逐步回归分析,仍具有统计学意义的变量为倒凹深度（P<0.05）。结论: 美学区种植同期应用异种骨行GBR术后愈合期间唇侧会有一定程度的骨吸收。患者年龄及牙槽嵴倒凹对GBR术后愈合期内种植体唇侧骨板的改建具有一定影响。牙槽嵴倒凹越大,GBR术后愈合期内唇侧骨板吸收越少。     

Bioabsorbable materials for guided bone regeneration prior to implant placement and 7-year follow-up: report of 14 cases

BACKGROUND: The purpose of the present study was to evaluate the efficacy of a guided bone regeneration (GBR) procedure prior to implant placement and the long-term outcome of the inserted implants. METHODS: Prior to dental implant placement, GBR procedure was performed on 14 patients (mean age 48 years) using a synthetic hydroxyapatite (HA) spacer under a collagen membrane. After a mean healing period of 8 months, bone biopsies were obtained during the placement of 14 implants. The specimens were processed for histology without demineralization in order to assess bone quality and quantity of the regenerated bone. RESULTS: Both the bone density and the resorption degree of HA particles were relatively varied between samples. The different phenotypes of osteoclasts and multinucleated giant cells and the individual host response could partially explain the unpredictable results in terms of bone remodeling and biomaterial resorption. However, the presence of HA particles in the regenerated bone had no influence on the osseointegration of implants presenting a success rate of 86% after a 7-year observation period. CONCLUSIONS: These results confirm the possibility of regenerating bone by means of bioabsorbable materials, assuring at the same time the long-term success for implants inserted in regenerated sites.     

Acellular dermal matrix graft as a membrane for guided bone regeneration: a case report

Guided bone regeneration has been successfully used to treat several types of bone defects. Problems associated with the procedure, such as premature exposure of the membranes to the oral cavity and, consequently, contamination, may occur. The acellular dermal matrix graft material is presently used to treat several soft tissue problems. It could be used for guided bone regeneration with the advantage of forming soft tissue while acting as a barrier membrane. A patient in need of guided bone regeneration for the staged placement of an implant was treated by using the acellular dermal matrix graft material as a barrier membrane. Healing progressed uneventfully with the formation of adequate new bone and an increase in the width of keratinized tissue.     

Effect of diabetes and metabolic control on de novo bone formation following guided bone regeneration

Objectives: To evaluate histologically and morphometrically the effect of experimental diabetes and metabolic control on de novo bone formation following guided bone regeneration (GBR). Methods: Thirty‐five Wistar rats were allocated in three experimental groups: (a) uncontrolled, streptozotocin‐induced diabetes (D); (b) insulin‐controlled diabetes (CD); (c) healthy (H). A standardised titanium microimplant with sandblasted and acid‐etched surface was placed into the inferior border of the mandible bilaterally. On the test site, the microimplant was covered with a titanium reinforced expanded polytetrafluoroethylene membrane securely fixed in the mandible according to the GBR principle. The contralateral site served as control. Following 90 days of healing, undecalcified sections were prepared and planimetric measurements of the per cent vertical height of newly formed bone and the per cent new bone‐to‐implant contact were performed. Results: In all experimental groups, at the GBR treated sites, significant neo‐osteogenesis was observed. The vertical height of the newly formed bone and per cent bone‐to‐implant contact were not statistically significantly different among the H (51.3±7.2% and 50±6.8%), D (30.5±13.4% and 35±16.8%) and CD (41.6±8.3% and 39.9±6.5%) groups. However, uncontrolled diabetes was related to higher outcome variability and increased rate of infectious complications. In the control sites, marginal bone loss was observed in the D group, whereas, in the H and CD groups, minimal new bone formation was observed. Conclusions: Significant de novo bone formation can be achieved via GBR treatment even in the presence of uncontrolled diabetes, although less predictably compared with the healthy status. Insulin‐mediated metabolic control may reverse these adverse effects. To cite this article: Retzepi M, Lewis MP, Donos N. Effect of diabetes and metabolic control on de novo bone formation following guided bone regeneration.
Clin. Oral Impl. Res. 21 , 2009; 71–79.     

美学区种植同期应用异种骨行引导骨再生术后愈合期间唇侧骨改建的临床研究

目的: 研究美学区种植同期应用异种骨行引导骨再生（GBR）术后愈合期间的唇侧骨改建。方法: 纳入2015年9月—2016年4月在上海交通大学医学院附属第九人民医院口腔种植科行GBR同期种植体植入的上前牙23例。术前、手术当天及二期手术阶段拍摄锥形束CT（CBCT）,记录牙龈厚度（>2 mm或≤2 mm）、骨质分类及使用的屏障膜。利用iCAT Vision数字化软件对种植体颈部肩台下2 mm（C）、体部中点（M）及根尖处（A）唇侧骨板进行测量,测量线与种植体长轴垂直。将纵切线向近中及远中各移动1 mm,得到新的纵切面,以同样方法测量唇侧骨板厚度并记录数值。在术前CBCT上测量牙槽嵴形态特征,记录牙槽嵴高度、倒凹深度及牙槽嵴宽度。采用SPSS 21.0软件包对数据进行统计学分析。结果: 种植体肩台下2 mm、体部中点及根尖处的平均骨吸收值分别为（0.70±0.59）mm、（0.85±0.72）mm和（0.55±0.51）mm,吸收率分别为23.07%、18.53%和12.97%。与植骨吸收相关的自变量中,相关分析表明,倒凹深度和年龄与植骨吸收量显著相关（P<0.05）;将所有变量纳入多重线性回归并行逐步回归分析,仍具有统计学意义的变量为倒凹深度（P<0.05）。结论: 美学区种植同期应用异种骨行GBR术后愈合期间唇侧会有一定程度的骨吸收。患者年龄及牙槽嵴倒凹对GBR术后愈合期内种植体唇侧骨板的改建具有一定影响。牙槽嵴倒凹越大,GBR术后愈合期内唇侧骨板吸收越少。     

Bone reconstruction following implantation of rhBMP-2 and guided bone regeneration in canine alveolar ridge defects

BACKGROUND: Alveolar ridge aberrations commonly require bone augmentation procedures for optimal placement of endosseous dental implants. The objective of this study was to evaluate local bone formation following implantation of recombinant human bone morphogenetic protein-2 (rhBMP-2) in an absorbable collagen sponge (ACS) carrier with or without provisions for guided bone regeneration (GBR) as potential treatment modalities for alveolar augmentation. METHODS: Surgically induced, large, mandibular alveolar ridge saddle-type defects (2 defects/jaw quadrant) in seven young adult Hound dogs were assigned to receive rhBMP-2/ACS, rhBMP-2/ACS combined with GBR (rhBMP-2/GBR), GBR, and surgery controls. The animals were euthanized at 12 weeks post-surgery when block sections of the defect sites were collected for histologic analysis. RESULTS: Clinical complications included swelling for sites receiving rhBMP-2 and wound failure with exposure of the barrier device for sites receiving GBR (4/6) or rhBMP-2/GBR (3/7). The radiographic evaluation showed substantial bone fill for sites receiving rhBMP-2/ACS, rhBMP-2/GBR, and GBR. In particular, sites receiving rhBMP-2/GBR presented with seroma-like radiolucencies. The surgery control exhibited moderate bone fill. To evaluate the biologic potential of the specific protocols, sites exhibiting wound failure were excluded from the histometric analysis. Sites receiving rhBMP-2/ACS or rhBMP-2/GBR exhibited bone fill averaging 101%. Bone fill averaged 92% and 60%, respectively, for sites receiving GBR and surgery controls. Bone density ranged from 50% to 57% for sites receiving rhBMP-2/ACS, GBR, or surgery controls. Bone density for sites receiving rhBMP-2/GBR averaged 34% largely due to seroma formation encompassing 13% to 97% of the sites. CONCLUSION: rhBMP-2/ACS appears to be an effective alternative to GBR in the reconstruction of advanced alveolar ridge defects. Combining rhBMP-2/ACS with GBR appears to be of limited value due to the potential for wound failure or persistent seromas.