Simultaneous sinus membrane elevation and dental implant placement without bone graft: a 6-month follow-up study

Background: Previous studies have shown that simultaneous elevation of the sinus mucosal lining and placement of dental implants without graft materials can be a predictable procedure. Nevertheless, few prospective, controlled, and randomized studies have evaluated this technique. The aim of this prospective, controlled, and randomized clinical study is to evaluate whether sinus membrane elevation and simultaneous placement of dental implants without autogenous bone graft can create sufficient bone support to allow implant success 6 months post‐surgically. Methods: Sinus membrane elevation and simultaneous placement of dental implants were performed bilaterally in 15 patients in a split‐mouth design. The sinuses were assigned to two groups: the test group, with simultaneous sinus mucosal lining elevation and placement of dental implants without graft materials; and the control group, with simultaneous sinus mucosal lining elevation and placement of dental implants with intraoral autogenous bone graft. After 6 months of healing, abutments were connected. For each implant, length of implant protrusion into the sinus, resonance frequency analysis, and bone gain were recorded at baseline and 6 months follow‐up. Results: Clinical complications were not observed, except for two postoperative fistulas and suppuration in both groups. Only one implant of the test group was lost, reaching a success rate of 96.4% and 100% for the test and control groups, respectively. After healing, radiographic new peri‐implant bone was observed in both groups ranging between 8.3 ± 2.6 and 7.9 ± 3.6 mm for the control and test groups, respectively (P >0.05). Resonance frequency analysis values were lower for the control group compared to baseline (P <0.05). However, these values were similar at 6 months (P >0.05). A significant positive correlation was found between the protruded implant length/bone gain and implant survival/sinusitis (P <0.0001). Conclusion: Implants placed simultaneously to sinus membrane elevation without graft material resulted in bone formation over a period of 6 months.     

Sinus bone formation and implant survival after sinus membrane elevation and implant placement: a 1- to 6-year follow-up study

Objectives: To investigate the long‐term clinical and radiographic results of the maxillary sinus membrane elevation technique where implants were inserted in a void space created by the elevation of the sinus membrane without adding any graft material. Materials and methods: A total of 84 patients were subjected to 96 membrane elevation procedures and simultaneous placement of 239 implants. Changes of intra‐sinus and marginal bone height in relation to the implants were measured in intraoral radiographs taken at insertion, after 6 months of healing, after 6 months of loading and then annually. Computerized tomography was performed pre‐surgically and 6 months post‐surgically. Resonance Frequency Analyses measurements were performed at the time of implants placement, at abutment connection and after 6 months of loading. The implant follow‐up period ranged from a minimum of one to a maximum of 6 years after implants loading. Results: All implants were stable after 6 months of healing. A total of three implants were lost during the follow‐up period giving a survival rate of 98.7%. Radiography demonstrated on average 5.3±2.1 mm of intra‐sinus new bone formation after 6 months of healing. RFA measurements showed adequate primary stability (implant stability quotient 67.4±6.1) and small changes over time. Conclusion: Maxillary sinus membrane elevation and simultaneous placement of implants without the use of bone grafts or bone substitutes result in predictable bone formation with a high implant survival rate of 98.7% during a follow‐up period of up to 6 years. The intra‐sinus bone formation remained stable in the long‐term follow‐up. It is suggested that the secluded compartment allowed for bone formation according to the principle of guided tissue regeneration. The high implant survival rate of 98.7% indicated that the implants sufficiently supported the fixed bridges throughout the study period. This technique reduces the risks for morbidity related to harvesting of bone grafts and eliminates the costs of grafting materials. To cite this article:
Cricchio G, Sennerby L, Lundgren S. Sinus bone formation and implant survival after sinus membrane elevation and implant placement: a 1‐ to 6‐year follow‐up study.
Clin. Oral Impl. Res. 22 , 2011; 1200–1212.
doi: 10.1111/j.1600‐0501.2010.02096.x     

Long-term results of implants treated with guided bone regeneration: a 5-year prospective study.

The aim of this prospective 5-year longitudinal study was to follow endosteal implants in which guided bone regeneration (GBR) was applied during implant placement. In 75 patients, defects around implants (Branemark System) were treated with Bio-Oss and Bio-Gide (112 implants). In split-mouth patients in this group, Bio-Oss and Gore-Tex were used in the second defect site (41 implants). All 75 patients had at least 1 implant that was entirely surrounded by bone and served as the control (112 implants). After placement of the definitive prostheses (single-tooth, fixed, or removable implant prostheses), patients were recalled after 6 months and then every 12 months during a 5-year observation period. The following variables were investigated: implant survival, marginal bone level (MBL), presence of plaque, peri-implant mucosal conditions, height of keratinized mucosa (KM), and marginal soft tissue level (MSTL). The cumulative implant survival rate after 5 years varied between 93% and 97% for implants treated with or without GBR. The mean MBL after 60 months was 1.83 mm for sites treated with Bio-Oss and Bio-Gide, 2.21 mm for sites treated with Bio-Oss and Gore-Tex, and 1.73 mm for the control sites. The MBL values were found to increase significantly with time and differed significantly among the treatment groups. During the observation period, KM varied between 3.16 and 3.02 mm. A slight recession of 0.1 mm was observed, and plaque was found in 15% of all sites and was associated with inflammatory symptoms of the peri-implant mucosa. It was observed that such symptoms and recession correlated more strongly with the type of restoration than with the type of treatment. This study demonstrated that implants placed with or without GBR techniques had similar survival rates after 5 years, but that bone resorption was more pronounced in sites with GBR treatment. It was assumed that the use of GBR is indeed indicated when the initial defect size is larger than 2 mm in the vertical dimension.     

Sinus floor elevation using anorganic bovine bone matrix (OsteoGraf/N) with and without autogenous bone: a clinical, histologic, radiographic, and histomorphometric analysis--Part 2 of an ongoing prospective study.

One of the goals of the sinus elevation procedure is the creation of vital bone to effect the osseointegration of dental implants placed in the posterior maxilla. With this goal in mind, in 1993 the Department of Implant Dentistry at New York University College of Dentistry began a long-term clinical, histologic, histomorphometric, and radiographic study of the sinus elevation procedure. The primary parameters included the effects of graft material selection, time allowed for graft maturation, and the effect of barrier membrane placement on the creation of vital bone in the sinus cavity. The effects of these and other parameters on implant survival rates were also to be evaluated. This paper reports the data collected on a subgroup of 113 sinus elevations that used anorganic bovine bone matrix (OsteoGraf/N) alone or in combination with autogenous bone and/or demineralized freeze-dried bone as a graft material. This is the second in a proposed series of papers that will result from this ongoing research project. The results of this study indicate that: OsteoGraf/N appears to be an effective graft material with a 98.2% implant survival rate to date: vital bone formation increased with time; vital bone formation increased moderately when demineralized freeze-dried bone allograft was added, and increased substantially when intraoral autogenous bone was added or when an expanded polytetrafluoroethylene membrane was used; and the increased height achieved by the procedure was stable over a 3-year period. Because of the high overall implant survival rate, it was not possible to determine the relationship between vital bone formation or membrane usage and implant survival.     

上颌窦底提升不植骨同期植入种植体的临床疗效观察

目的 观察冲压式上颌窦底提升术(osteotome sinus floor elevation,OSFE)不植骨并同期植入种植体的临床疗效及技术特点.方法 自2000年1月至2008年12月对65例患者经牙槽嵴顶入路,行OSFE并同期行种植体植入术,共植入96枚种植体,手术过程中上颌窦内不植入任何骨充填材料.缺牙区牙槽骨可用骨高度为5～8 mm,平均(6.78 4±1.04)mm.观察方法 为临床和X线片检查.对种植体凸入上颌窦内不同长度、安底改建情况进行卡方检验.结果 除1例单牙种植术后15 d因种植体松动、牙龈红肿取出种植体,其余64例患者随访>5年12例,>3年14例,>2年28例,>1年lO例,平均随访33.4个月.96枚种植体中除1枚于种植15 d后松动取bm外,其余种植体均获得良好的骨结合并完成上部义齿修复,种植体周围软组织无炎症,咀嚼功能良好.种植体凸入上颌窦内1～5 mm,平均2.57 mm,51枚(54%)种植体根方有不同程度的新骨形成,33枚(35%)种植体根方形成了新的上颌窦底,11枚(12%)种植体根周末见明显新骨形成.统计分析显示,种植体凸入上颌窦内的长度与上颌窦底骨改建差异无统计学意义(x2=6.113,P=0.191).结论 应严格把握OSFE适应证;OSFE时不植骨并同期植人种植体的短期临床效果是可预期的;新的窦底形成与上颌窦底提升高度无明显相关性.

Abstract：

Objective To investigate the clinical results of osteotome sinus floor elevation(OSFE)without grafting combined with simultaneous implant placement.Methods A total of 65 patients underwent maxillary sinus floor elevation from alveolus without any bone grafting from January 2000 to December 2008 and 96 implants were placed in the maxillary posterior edentulous region simultaneously.Clinical and radiography examinations were performed.The residual bone height ranged from 5 to 8 mm and the mean bone height was(6.78±1.04)mm.The mean following period was 33.4 months.Statistical analysis was perfbrmed by chi square test.Results Ninety-five of 96 implants were clinically stable and functioned without any pain and other complaints.One implant Was extracted 15 days after operation because of mobility and the other implants obtained osseointegration.The mean implant protrusion lengh Was 2.6 mm,ranging from 1 to 5 mm.Different degree of new bone formation was observed in 51(54%)of implants.New maxillary sinus floor outline Was observed in 33(35%)of implants and there was no obvious new bone in 11(12%)of implants.There Was no significant deference between the implant protrusion length and sinus floor remodeling.Conclusions Under strict indications,the clinical results of OSFE without bone grafting combined with simultaneous implant placement were predictable in short term.The new sinus floor formation was not related to the implant protrusion length.     

Histologic and clinical comparison of bilateral sinus floor elevations with and without barrier membrane placement in 12 patients: Part 3 of an ongoing prospective study

In 1993 the Department of Implant Dentistry at New York University College of Dentistry began a long-term clinical, histologic, histomorphometric, and radiographic study of the sinus elevation procedure. One of the parameters under evaluation in this study is the effect of barrier membrane placement on the creation of vital bone in the grafted sinus cavity. This report presents a histologic and histomorphometric evaluation of healing with and without the placement of an expanded polytetrafluoroethylene (e-PTFE) barrier membrane over the lateral window at the time of sinus grafting. The data were collected from 12 patients who underwent bilateral sinus elevation surgery. In each of these 12 patients the same grafting material was used in both sinuses, making the presence or absence of an e-PTFE barrier membrane the only controlled variable. Under the conditions of this study, the results indicate that (1) placement of the barrier membrane tends to increase vital bone formation; (2) placement of a barrier membrane has a positive effect on implant survival; and (3) membrane placement should be considered for all sinus elevation procedures.     

Bone reformation with sinus membrane elevation: a new surgical technique for maxillary sinus floor augmentation

Background: Various maxillary sinus floor augmentation techniques using bone grafts and bone substitutes are frequently used to enable placement of dental implants in the posterior maxilla. A previous case report demonstrated the possibility of promoting bone formation in the sinus by lifting the membrane without using a grafting material. However, the predictability of the technique is not known. Purpose: The aim of this study was to investigate whether sinus membrane elevation and the simultaneous insertion of titanium implants without additional grafting material constitute a valid technique for bone augmentation of the maxillary sinus floor. Materials and Methods: The study group comprised 10 patients in whom a total of 12 maxillary sinus floor augmentations were performed. A replaceable bone window was prepared in the lateral sinus wall with a reciprocating saw. The sinus membrane was dissected, elevated superiorly, and sutured to the sinus wall to create and maintain a compartment for blood clot formation. One to three dental implants were inserted through the residual bone and protruded at least 5 mm into the maxillary sinus. The bone window was replaced and secured with the overlying mucosa. Bone height was measured directly at each implant site at the time of insertion. Resonance frequency analysis (RFA) was performed on each implant at the time of initial placement, at abutment surgery, and after 12 months of functional loading. Computed tomography (CT) was performed in the immediate postoperative period and 6 months later, prior to exposure of the implants. Results: A total of 19 implants (Brånemark System®, TiUnite?, Nobel Biocare AB, Gothenburg, Sweden) in lengths of 10 to 15 mm were placed, with an average residual bone height of 7 mm (range, 4–10 mm). All implants remained clinically stable during the study period. Comparisons of pre‐ and postoperative CT radiography clearly demonstrated new bone formation within the compartment created by the sinus membrane elevation procedure. RFA measurements showed mean implant stability quotient values of 65, 66, and 64 at placement, at abutment connection, and after 12 months of loading, respectively. Conclusions: The study showed that there is great potential for healing and bone formation in the maxillary sinus without the use of additional bone grafts or bone substitutes. The secluded compartment created by the elevated sinus membrane, implants, and replaceable bone window allowed bone formation according to the principle of guided tissue regeneration. The precise mechanisms are not known, and further histologic studies are needed. Sinus membrane elevation without the use of additional graft material was found to be a predictable technique for bone augmentation of the maxillary sinus floor.     

Maxillary Sinus Floor Augmentation Surgery with Autogenous Bone Grafts as Ceiling: A Pilot Study and Test of Principle

Background: Studies have pointed out that the mere elevation of the maxillary sinus membrane might suffice to allow for bone formation indicating the additional use of augmentation materials to be redundant. Purpose: The purpose of this study was to assess whether elevation of the sinus mucosal lining combined with applying an autologous bone graft as a ceiling and placement of a short implant would allow for bone formation around the implant thus surpassing the need for applying augmentation materials around the installed implants. Materials and Methods: Fourteen consecutive patients were subjected to maxillary sinus floor elevation surgery and simultaneous placement of an implant. Using the lateral bone‐wall window technique, the membrane was exposed and elevated. Next, a bone graft taken from the zygomatic rim was placed as a ceiling above the inserted implant to ensure that the sinus membrane would not collapsed around a significant part of the implant. Finally, the bone window was returned in place. After connecting the healing abutment, the wound was closed. Results: All implants were stable and no implants were lost. There were no complications after harvesting the bone graft. Radiographic evaluation showed a bone gain of 3.2 ± 0.9 mm after 3 months and 3.6 ± 0.9 mm after 1 year. Less than 6% of the implant was not covered by bone after 1 year. Conclusion: Maxillary sinus membrane elevation and simultaneous placement of short endosseous implants with a bone graft as a ceiling on top of the implant result in predictable bone formation around the implant and good osseointegration on radiographs.     

牙周炎患者上颌窦提升术同期牙种植的临床观察

目的：对牙周炎患者行上颌窦内提升术同期植入种植体的临床效果进行评价。方法：收集2007年7月～2013年7月因上颌后牙缺失的慢性牙周炎患者25例,行单纯上颌窦内提升术并同期植入种植体43枚,修复后随访观察6～70个月。结果：观察期内种植体总留存率97．67％,窦底提升高度≥6mm者种植体留存率为94．44％。42枚种植体成功负载,无松动或脱落。所有牙周炎患者在随访期内均未发生上颌窦炎症,曲面断层片显示种植体根尖部与窦底之间可见新骨生成,种植体周围骨整合良好,窦底提升后上颌窦底至牙槽嵴顶的骨量明显增加。种植体周围软组织健康,无炎症,牙周探诊龈沟出血指数（SBI）0—1度。结论：对剩余骨高度不足的慢性牙周炎患者,上颌窦内提升术同期植入种植体可获得满意的临床效果。     

Bone reformation and implant integration following maxillary sinus membrane elevation: an experimental study in primates

Background: Recent clinical studies have described maxillary sinus floor augmentation by simply elevating the maxillary sinus membrane without the use of adjunctive grafting materials. Purpose: This experimental study aimed at comparing the histologic outcomes of sinus membrane elevation and simultaneous placement of implants with and without adjunctive autogenous bone grafts. The purpose was also to investigate the role played by the implant surface in osseointegration under such circumstances. Materials and Methods: Four tufted capuchin primates had all upper premolars and the first molar extracted bilaterally. Four months later, the animals underwent maxillary sinus membrane elevation surgery using a replaceable bone window technique. The schneiderian membrane was kept elevated by insertion of two implants (turned and oxidized, Brånemark System®, Nobel Biocare AB, Göteborg, Sweden) in both sinuses. The right sinus was left with no additional treatment, whereas the left sinus was filled with autogenous bone graft. Implant stability was assessed through resonance frequency analysis (Osstell^TM, Integration Diagnostics AB, Göteborg, Sweden) at installation and at sacrifice. The pattern of bone formation in the experimental sites and related to the different implant surfaces was investigated using fluorochromes. The animals were sacrificed 6 months after the maxillary sinus floor augmentation procedure for histology and histomorphometry (bone‐implant contact, bone area in threads, and bone area in rectangle). Results: The results showed no differences between membrane‐elevated and grafted sites regarding implant stability, bone‐implant contacts, and bone area within and outside implant threads. The oxidized implants exhibited improved integration compared with turned ones as higher values of bone‐implant contact and bone area within threads were observed. Conclusions: The amount of augmented bone tissue in the maxillary sinus after sinus membrane elevation with or without adjunctive autogenous bone grafts does not differ after 6 months of healing. New bone is frequently deposited in contact with the schneiderian membrane in coagulum‐alone sites, indicating the osteoinductive potential of the membrane. Oxidized implants show a stronger bone tissue response than turned implants in sinus floor augmentation procedures.     

Intrasinusal locking technique: a novel use of the ring block technique at sinus perforations for simultaneous implant placement

Ten patients who underwent sinus lift surgery with simultaneous implant placement using the intrasinusal locking technique were evaluated retrospectively. All patients were scheduled for sinus floor elevation procedures with simultaneous implant placement. Schneiderian membrane perforation occurred during the lifting procedure, and conventional methods failed to repair the perforation. Therefore, an autogenous bone ring was placed at the base of the maxillary sinus and was locked to the alveolar crest with a dental implant. Marginal resorption around the dental implants was measured on panoramic radiographs. Prosthetic rehabilitation was performed at 6 months postoperative. The overall survival rate of the implants over a mean follow-up of 24.3 months was 90%. One case failed due to resorption of the alveolar crest around the implant as a result of infection; the implant and the adjacent ring were removed at 1 month postoperative. At the time of writing, the nine implants placed using the documented technique continue to function well, without any signs of peri-implant disease. The proposed approach allows for simultaneous dental implant placement in the extremely atrophic maxilla, even if there is extensive perforation of the Schneiderian membrane.     

Long-term outcome of dental implants after maxillary augmentation with and without bone grafting

Background

This study aims to evaluate the technique of sinus bone reformation, which consists of elevating the sinus membrane and placement the implant without bone graft, compared with the widely-used technique involving raising the maxillary sinus and grafting, using animal hydroxyapatite as the filler, while simultaneously fixing the implants.

Material and Methods

This is a retrospective study on two groups of patients who underwent elevation of the sinus membrane and simultaneous placement of the implant. The grafting technique was applied to one group, while the other had no graft. An alveolar ridge height of 4 to 7 mm was necessary. Radiological control was undertaken at 6 months and one year post-prosthetic loading. In each group 38 implants were placed.

Results

No significant behavioural differences were observed in the implants according to the Albrektsson success criteria. Implant failure was observed in 2 implants from the bone grafting group (success rate 93%) and in 1 implant from the reformation group (success rate 97%). In this group, bone formation was observed on both sides of each implant, the bone gain was measured using image management software (2.7±0.9mm mesial and 2.6±0.9mm distal). There was no correlation between mesial and distal bone gain and implant´s length.

Conclusions

The results indicate that bone reformation is a valid technique in cases involving atrophy of the posterior maxilla. Primary stability, maintenance of space by the implant, and the formation of a blood clot are crucial in this technique in order to achieve bone formation around the implant. It is an alternative to the conventional technique of sinus lift with filling material, and has several advantages over this procedure, including a lower infection risk, as it does not involve a biomaterial, reduced cost, a simpler technique, and better acceptance by the patient. Key words:Bone formation, sinus membrane elevation, maxillary sinus, bone grafting.     

Sinus floor elevation utilizing the transalveolar approach

A transalveolar approach for sinus floor elevation with subsequent placement of dental implants was first suggested by Tatum in 1986. In 1994, Summers described a different transalveolar approach using a set of tapered osteotomes with increasing diameters. The transalveolar approach of sinus floor elevation, also referred to as ‘osteotome sinus floor elevation’, the ‘Summers technique’ or the ‘Crestal approach’, may be considered as being more conservative and less invasive than the conventional lateral window approach. This is reflected by the fact that more than nine out of 10 patients who experienced the surgical procedure would be willing to undergo it again. The main indication for transalveolar sinus floor elevation is reduced residual bone height, which does not allow standard implant placement. Contraindications for transalveolar sinus floor elevation may be intra‐oral, local or medical. The surgical approach utilized over the last two decades is the technique described by Summers, with or without minor modifications. The surgical care after implant placement using the osteotome technique is similar to the surgical care after standard implant placement. The patients are usually advised to take antibiotic prophylaxis and to utilize antiseptic rinses. The main complications reported after performing a transalveolar sinus floor elevation were perforation of the Schneiderian membrane in 3.8% of patients and postoperative infections in 0.8% of patients. Other complications reported were postoperative hemorrhage, nasal bleeding, blocked nose, hematomas and benign paroxysmal positional vertigo. Whether it is necessary to use grafting material to maintain space for new bone formation after elevating the sinus membrane utilizing the osteotome technique is still controversial. Positive outcomes have been reported with and without using grafting material. A prospective study, evaluating both approaches, concluded that significantly more bone gain was seen when grafting material was used (4.1 mm mean bone gain compared with 1.7 mm when no grafting material was utilized). In a systematic review, including 19 studies reporting on 4388 implants inserted using the transalveolar sinus floor elevation technique, the 3‐year implant survival rate was 92.8% (95% confidence interval: 87.4–96.0%). Furthermore, a subject‐based analysis of the same material revealed an annual failure rate of 3.7%. Hence, one in 10 subjects experienced implant loss over 3 years. Several of the included studies demonstrated that transalveolar sinus floor elevation was most predictable when the residual alveolar bone height was ≥ 5 mm and the sinus floor anatomy was relatively flat.     

Sinus floor elevation using a bovine bone mineral (Bio-Oss) with or without the concomitant use of a bilayered collagen barrier (Bio-Gide): a clinical report of immediate and delayed implant placement

Xenografts have been used extensively, either alone or in combination with autogenous bone, in sinus floor elevation techniques. However, controversy exists regarding the need to cover the lateral osteotomy site with a membrane. Also, the healing period before loading remains undefined when machined-surface implants are placed. Twenty-nine patients showing reduced bone volume in the posterior maxilla had 61 Br?nemark System implants placed in 30 sinuses augmented with a lateral osteotomy approach. Sinuses grafted with Bio-Oss and covered with a collagen membrane Bio-Gide (M+) received 29 implants, while grafted but uncovered sites (M-) received 32 implants. An immediate procedure was followed to place 41 implants and a staged procedure was used for 20 implants. Abutment connection was made in 2 distinct postoperative periods: 6 to 9 months and over 9 months. The patients were followed for an average of 22.4 months. The survival rate of the implants was dependent on the postoperative healing time and membrane presence. In case of the immediate procedure and in M- sites, when residual bone height was less than 5 mm, more failures occurred when the loading was done at 6 to 9 months than after 9 months. No failures occurred in the M- series when a staged approach was followed. The overall survival rate was 78.1% for the M- sites and 93.1% for the M+ sites. No failures occurred (0/35) in the control implants placed in adjacent native bone. Implant survival rate was related to the quality of the reconstructed cortical plate and to implant length. The concomitant use of a collagen barrier to cover the osteotomy site, when machined-surface implants were used in sinus grafting, seemed to improve the quality of the graft healing and survival rate of the implants loaded between 6 and 9 months after placement.     

Healing of dehiscence-type defects in implants placed together with different barrier membranes: a comparative clinical study

OBJECTIVE: Premature exposure of membranes used in guided bone regeneration (GBR) results in decreased bone formation. The effect of an expanded polytetrafluoroethylene (e-PTFE) and two collagen membrane on bone healing of buccal dehiscence defects around implants in cases with and without premature membrane exposure was clinically evaluated. METHODS: Three groups were established: Group OS (Ossix, n=73 implants, 41 patients), Group BG (Bio-Gide, n=53 implants, 28 patients) and Group GT (e-PTFE, Gore-Tex, n=34 implants, 17 patients). Defect height and width were measured at the time of implant placement and at second stage surgery. Surface area was calculated as half ellipses. When several implants were placed simultaneously, a mean of their defect width and height was calculated. RESULTS: Mean percentage reduction of defect area (92.2+/-13.78% Group OS, 94.6+/-6.69% Group BG, and 97.3+/-4.91% Group GT) and height (81.6+/-23.19%, 85.4+/-12.26%, and 93.4+/-9.39% respectively) did not show statistically significant differences between groups. Differences between groups were not statistically significant for all parameters when cases without spontaneous membrane exposure were compared. However, differences were significant when spontaneous membrane exposure occurred. Mean percentage reduction of defect area among cases where membrane exposure occurred was 91.5+/-10.86% Group OS, 71.5+/-8.61% Group BG, and 73.7+/-13.97% Group GT. Mean percentage reduction of defect height among cases with membrane exposure was 76.4+/-18.28%, 53.4+/-9.86%, and 49.4+/-11.05%, respectively. CONCLUSIONS: Premature exposure of membranes and subsequent and consequent exposure of implants results in impaired bone healing. Certain barrier membranes, as used in group OS, are apparently capable of supporting gingival healing even when prematurely exposed that could be advantageous in GBR procedures.     

Simultaneous dental implant placement and endoscope-guided internal sinus floor elevation: 2-year post-loading outcomes

Aims: To determine whether endoscope‐guided sinus elevation procedures can be consistently used to create sufficient bone support for stable implant placement and long‐term implant success. Material and methods: Sixty‐two implants were surgically placed into 30 patients (14 men and 16 women) following internal sinus elevation without the use of graft material. Panoramic radiographs were made pre‐, post‐operative and after 24 months in order to evaluate the peri‐implant bone and maxillary sinuses. Resonance frequency analysis (RFA) was used to evaluate implant stability immediately upon placement and just before prosthesis delivery. Results: The average pre‐operative height of the maxillary alveolar bone was 8.4±2.2 mm at the premolar and 7.3±3.1 mm at the molar regions. The average bone gain was 3.5±1.8 and 4.5±1.9 mm in the premolar and molar sites, respectively. Clinical parameters and the RFA (4 and 12 weeks post‐operative) outcomes show sufficient stability (ISQ=60) of the inserted implants. Three implants failed during the healing period of 12 weeks. The overall implant success rate was 94%. After loading, no further implant failure was observed. The overall success rate after beginning of implant loading was 100%. Conclusions: Sinus floor elevation is a well‐established procedure for augmentation of the atrophic maxillary posterior region. The minimally invasive internal sinus floor elevation procedure visually guided by an endoscope helped to prevent, diagnose and manage complications such as sinus membrane perforation. The clinical outcomes of this study show that endoscope‐controlled internal sinus floor elevation combined with implant placement results in low intra operative trauma, good implant stability upon placement, low incidence of post‐operative symptoms and high success rates after 24 months of loading.     

上颌窦内提升术植骨与不植骨对种植体骨结合的影响

目的探讨上颌窦内提升术植骨与不植骨对种植体骨整合的影响及两者之间的差异。方法将120枚需要进行内提升手术的种植体随机平均分为两组,第一组60枚为实验组,在上颌窦内提升后植入骨材料同期植入种植体;第二组60枚为对照组,上颌窦内提升后不植骨同期植入种植体。对两组种植体进行临床追踪（平均18个月）,观察种植体骨整合、临床检查指标、种植体存留率及影像学变化。结果仅有1例种植体覆盖螺丝暴露,种植体颈部出现骨吸收。所有两组种植体均能完成修复,种植体存留率达到100%,无1例脱落。种植体均能正常行使咀嚼功能,骨整合良好。影像学检查种植体周围均有新骨生长,骨整合良好。结论上颌窦内提升术后不植骨可以取得与植骨同样的效果,可以明显减少患者的种植牙费用,是一种值得推广应用的手术方法。     

Bone quality at the implant site after reconstruction of a local defect of the maxillary anterior ridge with chin bone or deproteinised cancellous bovine bone

The purpose of this study was to investigate the quality of bone at grafted implant sites in the anterior maxilla. Grafting of these sites was necessary because of insufficient bone volume in a buccopalatinal direction (width at the top of the crest 1-3mm). Reconstruction was performed with chin bone (N=5), chin bone and a resorbable Bio-Gide((R)) GBR membrane (N=5) or Bio-Oss((R)) spongiosa granules in combination with a Bio-Gide((R)) GBR membrane (N=5). Biopsies were taken prior to implantation, i.e. 3 months after grafting with chin bone, and 6 months after grafting with Bio-Oss((R)). Evaluation was done by assessing the histological and histomorphometric characteristics of full-length biopsies taken from the actual implant site. Both areas with non-vital bone and areas with apposition of bone and remodelling phenomena were observed in the chin bone group at the time of placement of the implants. Similar results were observed at implant sites reconstructed with a chin bone graft covered by a membrane. In the chin bone group without and with a GBR membrane, the mean total bone volume (TBV) was 55.2+/-6.8% and 57.7+/-11.5%, respectively; the marrow connective tissue volume (MCTV) was 44.8+/-6.8% and 42.3+/-11.5%, respectively. Remnants of the resorbable GBR membrane were not detected. In the Bio-Oss((R)) group, at implant placement some newly formed bone was observed in the connective tissue surrounding the Bio-Oss((R)) particles (mean TBV (newly formed bone) 17.6+/-14.5%), but most particles were surrounded by connective tissue. No convincing signs of remodelling were observed (mean remaining Bio-Oss((R)) volume 40.5+/-9.3%; mean MCTV 41.9+/-13.1%). No implants were lost during follow up (12 months). At the time of placement of the implants the grafting material (either chin bone or Bio-Oss((R))) is still not fully replaced by new vital bone. In case of Bio-Oss((R)), most of the grafting material is even still present. Despite these differences, the 1-year clinical results were very good and comparable between the various grafting techniques applied.     

Lateral sinus floor elevation without grafting materials. Individual- and aggregate-data meta-analysis

Purpose

To perform a systematic review and individual- and aggregate-data meta-analysis of observational studies to determine the success rate of the lateral sinus floor elevation with simultaneous implant placement and without grafting materials.

Flapless approach to maxillary sinus augmentation using minimally invasive antral membrane balloon elevation

In the atrophic posterior maxilla, successful implant placement is often complicated by the lack of quality and volume of available bone. In these cases, sinus floor augmentation is recommended to gain sufficient bone around the implants. Sinus elevation can be performed by either an open lateral window approach or by a closed osteotome approach depending on available bone height. This case series demonstrates the feasibility and safety of minimally invasive antral membrane balloon elevation, followed by bone augmentation and implant fixation in 20 patients with a residual bone height of 2 to 6 mm below the sinus floor. The surgical procedure was performed using a flapless approach. At 18 months follow-up, the implant survival rate was 100%. Absence of patient morbidity and satisfactory bone augmentation with this minimally invasive procedure suggests that minimally invasive antral membrane balloon elevation should be considered as an alternative to some of the currently used methods of maxillary bone augmentation.