A prospective clinical study of bone augmentation techniques at immediate implants

The efficacy of combinations of membranes and autogenous bone grafts at immediate implants were compared in a prospective study. Sixty-two consecutively treated patients each received an immediate implant for a single tooth replacement at a maxillary anterior or premolar site. Dimensions of the peri-implant defect at the implant collar were measured as follows: vertical defect height (VDH), horizontal defect depth (HDD) and horizontal defect width (HDW). Each implant randomly received one of five augmentation treatments and were submerged with connective tissue grafts: Group 1 (n=12)--expanded polytetrafluoroethylene membrane only, Group 2 (n=11)--resorbable polylactide/polyglycolide copolymer membrane only, Group 3 (n=13)--resorbable membrane and autogenous bone graft; Group 4 (n=14)--autogenous bone graft only, and Group 5 (n=12)--no membrane and no bone graft control. At re-entry, all groups showed significant reduction in VDH, HDD and HDW. Comparisons between groups showed no significant differences for VDH (mean 75.4%) and HDD (mean 77%) reduction. Significant differences were observed between groups for HDW reduction (range, 34.1-67.3%), with membrane-treated Groups 1, 2 and 3 showing the greatest reduction. In the presence of dehiscence defects of the labial plate, HDW reduction of 66.6% was achieved with membrane use compared with 37.7% without membranes. Over 50% more labial plate resorption occurred in the presence of a dehiscence defect irrespective of the augmentation treatment used. The results indicate that VDH and HDD reduction at defects adjacent to immediate implants may be achieved without the use of membranes and/or bone grafts.     

钛膜在上颌前牙区骨缺损延期即刻种植术中的临床应用观察

目的：通过钛膜在前牙区骨缺损的延期即刻种植术的应用,观察其成骨效果。方法：选取12例前牙区骨缺损病例,拔除患牙4-6周后,植入种植体,钛膜覆盖骨缺损区,6个月后二期手术观察成骨效果并完成冠修复。结果：共植入Frialit-2种植体16个,钛膜19片。2片钛膜术后2周发生部分暴露,予以再次缝合关闭创面。其余钛膜固位良好。术后6个月成骨效果满意。16个种植体均稳固,修复效果良好。结论：钛膜具有良好的引导骨再生作用,在前牙区骨缺损延期即刻种植中可发挥良好的成骨作用。     

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.     

Prognostic factors for alveolar regeneration: bone formation at teeth and titanium implants

OBJECTIVES: There is a limited understanding of the effect of defect characteristics on alveolar bone healing. The objectives of this study were to assess the effect of alveolar bone width and space provision on bone regeneration at teeth and titanium implants, and to test the hypothesis that the regenerative potentials at teeth and implants are not significantly different. METHODS: Critical size, 5-6-mm, supra-alveolar, periodontal defects were surgically created in 10 young adult dogs. Similarly, critical size, 5-mm, supra-alveolar, peri-implant defects were created in four dogs. A space-providing expanded polytetrafluoroethylene device was implanted for guided tissue regeneration/guided bone regeneration. The animals were euthanized at 8 weeks postsurgery. Histometric analysis assessed alveolar bone regeneration (height) relative to space provision by the device and the width of the alveolar crest at the base of the defect. Statistical analysis used the linear mixed models. RESULTS: A significant correlation was found between bone width and wound area (r=0.55892, p<0.0001). Generally, bone width and wound area had statistically significant effects on the extent of bone regeneration (p<0.0005 and p<0.0001, respectively). Bone regeneration was linearly correlated with the bone width at periodontal (p<0.001) and implant (p=0.04) sites, and with the wound area at periodontal (p<0.0001) and implant (p=0.03) sites. The relationships of bone regeneration with these two variables were not significantly different between teeth and implants (bone width: p=0.83; wound area: p=0.09). When adjusted for wound area, bone regeneration was significantly greater at periodontal than at implant sites (p=0.047). CONCLUSIONS: The horizontal dimension of the alveolar bone influences space provision. Space provision and horizontal dimension of the alveolar bone appear to be important determinants of bone regeneration at teeth and implants. The extent of alveolar bone formation at implant sites is limited compared with that at periodontal sites.     

A prospective clinical study of non-submerged immediate implants: clinical outcomes and esthetic results

OBJECTIVES: To evaluate healing of marginal defects in immediate transmucosal implants grafted with anorganic bovine bone, and to assess mucosal and radiographic outcomes 3-4 years following restoration. MATERIAL AND METHODS: Thirty immediate transmucosal implants in maxillary anterior extraction sites of 30 patients randomly received BioOss (N=10; BG), BioOss and resorbable collagen membrane (N=10; BG+M) or no graft (N=10; control). RESULTS: Vertical defect height (VDH) reductions of 81.2+/-5%, 70.5+/-17.4% and 68.2+/-16.6%, and horizontal defect depth (HDD) reductions of 71.7+/-34.3%, 81.7+/-33.7% and 55+/-28.4% were observed for BG, BG+M and control groups, respectively, with no significant inter-group differences. Horizontal resorption was significantly greater in control group (48.3+/-9.5%) when compared with BG (15.8+/-16.9%) and BG+M (20+/-21.9%) groups (P=0.000). Ten sites (33.3%) exhibited recession of the mucosa after 6 months; eight (26.7%) had an unsatisfactory esthetic result post-restoration due to recession. Mucosal recession was significantly associated (P=0.032) with buccally positioned implants (HDD 1.1+/-0.3 mm) when compared with lingually positioned implants (HDD 2.3+/-0.6 mm). In 19 patients followed for a mean of 4.0+/-0.7 years, marginal mucosa and bone levels remained stable following restoration. CONCLUSION: BioOss significantly reduced horizontal resorption of buccal bone. There is a risk of mucosal recession and adverse soft tissue esthetics with immediate implant placement. However, this risk may be reduced by avoiding a buccal position of the implant in the extraction socket.     

改良式引导骨再生术+即刻修复技术在上前牙即刻种植中的应用评价

目的评估一种改良式引导骨再生术(guided bone regeneration,GBR)+即刻修复技术在上前牙即刻种植中的应用效果,特别是美学效果,并探讨其临床技巧及美学影响因素。方法选择15例单颗上前牙进行即刻种植,微创拔牙后即刻植入Replace、Straumann或Ankylos种植体共15枚,采用改良式GBR+即刻修复,均于2 h内完成临时修复。4⁶个月后完成最终修复。种植修复完成后随访66个月后完成最终修复。种植修复完成后随访6²4个月,观察种植体周围软硬组织情况,统计种植义齿存留率、种植修复体与相邻天然牙唇侧牙龈的协调性和患者主观满意度。结果在观察期内,15枚种植体均获得了良好的骨结合,无松动,未见病理性骨吸收,存留率为100%;12枚种植修复体唇侧龈缘位置与邻牙协调无差异,3枚轻度差异;14枚种植修复体与邻牙牙龈颜色质地协调无差异,1枚轻度差异。患者主观满意度VAS平均值为92。结论改良式GBR+即刻修复技术在上前牙即刻种植中,有助于获得理想的前牙美学效果,缩短治疗周期。     

Effect of barrier membranes and autologous bone grafts on ridge width preservation around implants

Background: The purpose of this study was to explore the effect of barrier membranes and autologous bone grafts on the preservation of ridge width around implants. Materials and Methods: Sixty‐one patients were chosen from a database of case series; treatment assignment was based on clinical judgment. The patients received a total of 76 implants:34 implants with guided tissue regeneration procedures, 27 with autologous bone grafts, and 15 without ridge preservation procedures (control group). Results: The ridge width around the 76 implants decreased an average of 1.4 mm (95% CI, ‐1.9 to‐1.1 mm). Implants placed with autologous bone grafts or membranes tended to have worse outcomes. When compared to the no augmentation group, implants placed with guided tissue regeneration and autologous bone grafts resulted in 0.1 mm of additional bone loss (95% CI, ‐1.7 to ‐1.5 mm; p <.93) and 0.8 mm of additional bone loss (95% CI, ‐2.3 to 0.7 mm; p <.28), respectively. Conclusions: Autologous graft procedures or barrier membranes do not appear to improve crestal ridge preservation around implants.     

Replacement of teeth exhibiting periapical pathology by immediate implants: a prospective, controlled clinical trial

OBJECTIVES: The aim of the present study was to test whether or not immediate implantation leads to more biological complications, when performed at extraction sockets of teeth exhibiting periapical pathology compared with teeth not exhibiting periapical pathology. MATERIALS AND METHODS: In 17 consecutively admitted patients, immediate implant placement was planned in order to replace single teeth exhibiting periapical pathology (test group). These teeth demonstrated pain, periapical radiolucency, fistula, suppuration or a combination of these findings. Another 17 consecutively admitted patients in need of single tooth replacement in the absence of periapical pathology served as the control group. Implant placement and accompanying bone regeneration were performed according to standard clinical procedures. Implants were loaded after a healing period of 3 months. Clinical and radiographical parameters were assessed at the time of implant placement (baseline) and at 12 months thereafter. RESULTS: Out of the 34 patients, four test and one control patient had to be withdrawn from the study due to the inability to obtain primary implant stability. The residual 29 implants revealed a survival rate of 100% 1 year after placement. Clinical and radiographical differences between 12 months and baseline comparing test and control groups showed no statistical significances for any of the parameters assessed. Within test and control groups there was a statistically significant loss of vertical bone height at the adjacent teeth (mesial test=0.4+/-0.6 mm, control=0.4+/-0.5 mm; distal test=0.3+/-0.2 mm, control=0.7+/-0.8 mm) as well as at the implant site (mesial test=1.9+/-1.4 mm, control=1.8+/-1.1 mm; distal test=1.7+/-1.4 mm, control=1.6+/-1.1 mm) and of buccal keratinized mucosa (test=-2.2+/-1.2 mm; control=-1.3+/-1.6 mm) between baseline and 12 months. During the first 13 weeks of healing, two sites of the test and one site of the control group showed signs of infection, which required intervention. Neither the incident of early exit nor of signs of infection was statistically significantly different between the test and the control group (Mann-Whitney U test). CONCLUSION: It is concluded that for those implants where primary stability was achieved, the immediate implant placement performed at extraction sockets exhibiting periapical pathology did not lead to an increased rate of complications and rendered an equally favorable type of tissue integration of the implants in both groups. Implant placement into such sites can, therefore, be successfully performed.     

Immediate implants with immediate loading vs. conventional loading: 1-year randomized clinical trial

Purpose: This 1‐year randomized clinical trial compared the bone regeneration and success rates between immediate and conventional loading of dental implants placed immediately after extraction in patients with a past history of periodontal disease. Methods: Sixty patients who chose an immediate implant treatment option to replace a hopeless tooth were included in this study. Patients: Patients were randomly assigned to receive immediate implants with either immediate loading (group A) or conventional loading after 3 months (group B). At baseline, both groups received a mucoperiosteal flap, extraction, implant placement, allograft bone, and a membrane. Group A received a provisional crown. In group B, a cover screw was placed and primary closure was achieved. The patients were evaluated at 3, 6, and 12 months postoperatively. Results: The 1‐year implant survival rate was 95% for the whole study group: 96.6% for group A, and 93.3% for group B. The bone level increased significantly in both groups (group A: 0.99 ± 0.22 mm; group B: 0.75 ± 0.17 mm), and the difference was not statistically significant (p > 0.5). At the 1‐year postoperative visit, the mucogingival junction (MGJ) was found to be displaced coronally in 65% of implant sites in group B compared with 15% sites in group A. Conclusions: Both the immediate and delayed loading of immediately placed implants showed similar outcome with regards to treatment success rates and stability of radiographic bone level. Submerging an immediately placed implant and primary soft tissue closure did not show significant outcome advantages over the transmucosal approach.     

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由于种植体生物相容性的不断改良和完善,目前的牙种植体均能获得理想的可预期的骨结合,在新拔除患牙的牙槽窝内即刻植入种植体已经成为一种常规的术式拔牙后即刻种植可有利于减少外科手术次数,有利于牙槽嵴骨量的保存,降低治疗费用并减少缺牙时间,更易被患者接受.但由其解剖生理因素决定,牙槽嵴在牙缺失后通常要出现唇侧骨板的吸收萎缩,这常导致种植体唇面暴露,出现美学上的问题.即刻种植的同时,在充分理解和使用引导骨再生原理的基础上配合骨增量材料的应用才能获得理想的修复效果,本文就我们的临床体会结合文献进行了分析讨论.     

骨替代材料在口腔种植领域中的成骨效果

骨替代材料目前已成为拔牙位点保存术、牙槽嵴骨增量术和上颌窦底提升术的主要材料,而羟磷灰石、磷酸钙和生物活性玻璃以其良好的生物相容性、骨传导性、生物降解性、骨再生能力和骨结合率成为骨替代材料的代表.单一成分骨替代材料的诱导骨再生能力取决于材料本身的表面形貌、结构、成分、孔径和孔隙率.按不同比例复合的新型骨替代材料,可使原单一骨替代材料的性能得以互补.骨替代材料与血小板浓缩物的联合应用,可促进前成骨细胞的增殖与分化,激发成骨细胞的活动,促进血管新生,从而利于骨替代材料存活.骨替代材料与生长因子的联合应用,可获得不同程度骨结合和骨改建,增加材料的细胞黏附率,改善支架的力学性能,在骨愈合早期即能促进新骨形成.随着科技的进步,未来骨替代材料的成骨性能日臻完善,在口腔种植领域的应用前景将会更加广阔.     

Guided bone regeneration around dental implants in the atrophic alveolar ridge using a bioresorbable barrier. An experimental study in the monkey.

The aim of this study was to evaluate guided bone regeneration (GBR) around dental implants placed in atrophic alveolar ridges using an experimental, nonporous bioresorbable barrier. In 8 Rhesus monkeys, the maxillary canines and lateral incisors were extracted bilaterally and the remaining alveoli were reduced to create atrophic ridges. After a healing period of 3 months, soft tissue expansion was performed using a subperiosteal tissue expander. After 1 month of tissue expansion, an IMZ implant was placed in the atrophic ridge on each side in such a way that its coronal 4 mm to 5 mm remained circumferentially exposed above the bone level. The test implants were covered with a bioresorbable barrier made of poly (D,L‐lactid‐co‐tri‐methylencarbonate) in a 70/30 ratio, whereas the control implants were covered with a nonresorbable expanded polytetrafluoroethylene (e‐PTFE) barrier. The e‐FTFE barriers were stabilized with titanium minipins while the bioresorbable barriers were analogously fixed using bioresorbable minipins made of poly (L‐lactid‐co‐D,L‐lactid) 70/30. Clinical healing progressed uneventfully in both groups and no soft tissue dehiscences occurred. Histometric and histomorphometric analyses were performed 5 months post surgery. Both test and control implants exhibited direct bone‐to‐implant contact to variable extents. The mean direct mineralized bone‐to‐implant contact length fraction was 32% of the total implant length in the test sites and 58% in the control sites. Control sites exhibited significantly greater bone fill compared to the experimental sites ( P <0.00l). Histologic observations of test specimens demonstrated a moderate inflammatory reaction related to the degradation and resorption products of the barrier. In conclusion, the nonresorbable e FTFE GBR barrier was found to be superior to the bioresorbable barriers tested in the present investigation.     

GBR技术应用于上前牙种植骨缺损的临床研究

目的：评估引导骨再生技术（GBR）在上前牙不同类型骨缺损种植修复中的效果。方法：对35例上前牙牙槽骨缺损种植的患者采用GBR技术进行骨增量,其中29例种植体周围骨缺损患者仅采用GBR技术,在植体植入骨床后,同期植入Bio～oss人工骨粉,表面盖Bio～gide可吸收性胶原膜;6例牙槽骨缺损患者采用移植自体块状骨联合Bio～oss人工骨粉,盖Bio～gide可吸收性胶原膜,5～6个月后行Ⅱ期种植体植入术。结果：所有患者在植体植入术后6～12个月临床观察种植体与骨结合良好,软组织形态与周围组织一致,行冠或桥修复,修复后12个月随诊复查无种植体失败。结论：引导骨再生技术皆能有效地对上前牙不同类型骨缺损进行骨增量,符合美学种植要求。