Implant survival rates after maxillary sinus augmentation

Implant therapy in the atrophic posterior maxilla becomes challenging in the presence of reduced maxillary bone height. Sinus augmentation can be performed for resolving this condition prior to implant placement. The aim of this article was therefore to evaluate implant survival rates in the grafted sinus taking into account the influence of the implant surface, graft material, and implant placement timing. A systematic review of the literature was performed. Articles retrieved from electronic databases were screened using specific inclusion criteria, and data extracted were divided according to: graft material (autogenous, non‐autogenous, composite graft), implant surface (machined or textured), and implant placement (simultaneous with grafting or delayed). Fifty‐nine articles were included. Survival rates for implants placed in grafts made of bone substitutes alone and grafts of composite material were slightly better than the survival rates for implants placed in 100% autogenous grafts. Over 90% of implants associated with non‐autogenous grafts had a textured surface. Textured surfaces achieved better outcomes compared with machined surfaces, and this was independent of the graft material. Simultaneous and delayed procedures had similar outcomes. It may be concluded that bone substitutes can be successfully used for sinus augmentation, reducing donor‐site morbidity. Long‐term studies are needed to confirm the performance of non‐autogenous grafts. The use of implants with a textured surface may improve the outcome in any graft type.     

Maxillary sinus lift with solely autogenous bone compared to a combination of autogenous bone and growth factors or (solely) bone substitutes. A systematic review

Literature regarding the outcome of maxillary sinus floor elevation to create sufficient bone fraction to enable implant placement was systematically reviewed. Bone fraction and implant survival rate were assessed to determine whether grafting material or applied growth factor affected bone fraction. Trials where sinus floor elevations with autogenous bone (controls) were compared with autogenous bone combined with growth factors or bone substitutes, or solely with bone substitutes (test groups) were identified; 12 of 1124 fulfilled all inclusion criteria. Meta-analyses comparing the bone fraction after applying: autogenous bone; autologous bone with growth factors (platelet rich plasma); or autogenous bone and bone substitutes (bovine hydroxyapatite, bioactive glass, corticocancellous pig bone) revealed no significant differences in bone formation after 5 months. A significantly higher bone fraction was found in the autogenous bone group compared to the sole use of β-tricalciumphosphate (P=0.036). The one-year overall implant survival rate showed no significant difference between implants. Bone substitutes combined with autogenous bone provide a reliable alternative for autogenous bone as sole grafting material to reconstruct maxillary sinus bony deficiencies, for supporting dental implants after 5 months. Adding growth factors (platelet rich plasma) to grafting material and the sole use of β-tricalciumphosphate did not promote bone formation.     

Sinus augmentation bone grafts for the provision of dental implants: report of clinical outcome

PURPOSE: The aim of this study was to report the outcome of sinus augmentation surgery with autogenous bone grafting in routine dental implant practice. MATERIALS AND METHODS: Twenty-seven sinus augmentation procedures were undertaken on 18 consecutive patients (mean age 43.7 years). The mandibular symphysis was used as the donor site for 11 patients. The iliac crest was used as a donor site for 7 bilateral cases. RESULTS: Six patients had implants placed at the time of grafting: the other 13 had a mean bone graft consolidation period of 24.7 weeks (range 9 to 39 weeks) before implants were placed. One patient who had a repeat procedure had both immediate and delayed techniques. A total of 79 Br?nemark System Mk II implants were placed in grafted bone (and 2 Mk IV implants were placed in a patient who had to have a repeat procedure) and proceeded to occlusal loading. After a mean follow-up period of 162 weeks (range 76 to 288 weeks), 16 implants failed to integrate in grafted bone, representing an 80.25% survival rate. Fourteen patients proceeded to the planned prosthesis, 3 patients had a compromised treatment plan, and 1 patient was restored conventionally. This represents 94% of patients who were rehabilitated. DISCUSSION AND CONCLUSION: The sinus augmentation procedure using autogenous bone grafting can Increase bone volume to allow implant placement where there is insufficient bone. The survival of implants in the grafted bone, as measured by integration and successful loading, was reduced compared to implants placed in normal maxillary bone. Infection during the healing of the grafted site reduces the success of subsequent implant osseointegration.     

A systematic review of the success of sinus floor elevation and survival of implants inserted in combination with sinus floor elevation

Objectives: The objectives of this systematic review were to assess the survival rate of grafts and implants placed with sinus floor elevation.
Material and Methods: An electronic search was conducted to identify studies on sinus floor elevation, with a mean follow-up time of at least 1 year after functional loading.
Results: The search provided 839 titles. Full-text analysis was performed for 175 articles resulting in 48 studies that met the inclusion criteria, reporting on 12,020 implants. Meta-analysis indicated an estimated annual failure rate of 3.48% [95% confidence interval (CI): 2.48%–4.88%] translating into a 3-year implant survival of 90.1% (95% CI: 86.4%–92.8%). However, when failure rates was analyzed on the subject level, the estimated annual failure was 6.04% (95% CI: 3.87%–9.43%) translating into 16.6% (95% CI: 10.9%–24.6%) of the subjects experiencing implant loss over 3 years.
Conclusion: The insertion of dental implants in combination with maxillary sinus floor elevation is a predictable treatment method showing high implant survival rates and low incidences of surgical complications.
The best results (98.3% implant survival after 3 years) were obtained using rough surface implants with membrane coverage of the lateral window.     

Healing in smokers versus nonsmokers: survival rates for sinus floor augmentation with simultaneous implant placement

PURPOSE: Evidence suggests that smoking is detrimental to the survival of dental implants placed in grafted maxillary sinuses. Studies have shown that improving bone quantity and quality, using rough-surfaced implants, and practicing good oral hygiene may improve outcomes. In this prospective study, the long-term survival rates of implants placed simultaneously with sinus grafting in smokers and nonsmokers were compared. MATERIALS AND METHODS: Implants with roughened surfaces were immediately placed into maxillary sinus grafts in patients with 1 to 7 mm of residual bone. A total of 2132 simultaneous implants were placed into the grafted sinuses of 226 smokers (627 implants) and 505 nonsmokers (1505 implants). A majority of the patients received a composite graft consisting of 50% autogenous bone. In both smokers and nonsmokers, approximately two thirds of the implants had microtextured surfaces; the remainder had hydroxyapatite-coated surfaces. The implants were restored and monitored during clinical follow-up for up to 9 years. RESULTS: Cumulative survival of implants at 9 years was 97.9%. There were no statistically significant differences in implant failure rates between smokers and nonsmokers. DISCUSSION: Implant survival was believed to depend on the following aspects of the technique used: creation of a large buccal window to allow access to a large recipient site; use of composite grafts consisting of at least 50% autogenous bone; meticulous bone condensation; placement of long implants (i.e., 15 mm); use of implants with hydroxyapatite-coated or microtextured surfaces; use of a membrane to cover the graft and implants; antibiotic use and strict oral hygiene; use of interim implants and restricted use of dentures; and adherence to a smoking cessation protocol.     

A prospective 1-year clinical and radiographic study of implants placed after maxillary sinus floor augmentation with bovine hydroxyapatite and autogenous bone.

PURPOSE: The purposes of this study were 1) to evaluate the survival rate of implants placed in maxillary sinuses augmented with bovine hydroxyapatite and autogenous bone 6 months before implant surgery and 2) to estimate dimensional changes of the bone graft with time using a new radiographic method. PATIENTS AND METHODS: Thirty maxillary sinuses in 20 consecutive patients with severe resorption (mean, 3.8 mm of remaining alveolar bone) were augmented with a mixture of 80% bovine hydroxyapatite and 20% autogenous bone mixed with fibrin glue to enable the placement of screw-shaped dental implants. After 6 months of primary healing, 108 implants were placed and followed with clinical and radiographic examinations during the first year of loading. Measurements of changes in height, width, and length of the grafted material were made on tomographic Scanora (Soredex Orion Corporation Ltd, Helsinki, Finland) and panoramic radiographs taken 3 and 12 months after grafting and after 1 year of bridge loading. RESULTS: Ten implants in 6 patients were lost during the study (9 before loading and 1 after 1 year of functional loading), for a survival rate of 90.7%. All patients received fixed restorations, and the bridge survival rate was 100% after 1 year of loading. Small (<10%) but statistically significant dimensional changes in the grafted material were seen during the study period. CONCLUSIONS: Acceptable short-term results can be obtained with implants placed after the use of bovine hydroxyapatite and autogenous bone for maxillary sinus floor augmentation. These grafts show good resistance to resorption.     

Predictability of simultaneous implant placement in the severely atrophic posterior maxilla: A 9-year longitudinal experience study of 2132 implants placed into 731 human sinus grafts

PURPOSE: One-stage implant placement in the grafted maxillary sinus has traditionally been limited to patients with at least 5 mm of residual bone to ensure complete implant stabilization. The aim of this prospective study was to determine the long-term survival rates of implants with roughened surfaces placed immediately into maxillary sinus grafts in patients with 1 to 5 mm of residual bone. MATERIALS AND METHODS: A total of 2132 microtextured screw-type (n=1374) or hydroxyapatite-coated cylinder-type (n=758) implants were immediately placed into the grafted sinuses of 731 patients. The implants were restored and monitored for up to 9 years of clinical follow-up. RESULTS: Cumulative survival at 9 years was 97.9% (n=2091 implants); 20.4% of the implants were placed in 1 to 2 mm of residual bone. Discussion: Initial implant stability and parallelism were achieved through a combination of meticulous condensation of the particulate bone graft material around the implants, the frictional interface of the roughened implant surfaces and the host tissues, and selection of an appropriate graft material. CONCLUSIONS: Simultaneous implant placement into sinus floor grafts can be a predictable treatment option for patients with at least 1 to 2 mm of vertical residual bone height when careful case planning and meticulous surgical techniques are used.     

Clinical and histopathological study of simus lift procedure

Sixteen sinuses of 11 patients performed by sinus lift procedure were retrospectively discussed clinically and histopathological investigations from grafted materials. Grafted materials were 10 autogenous bones harvested from 1 iliac crest and 9 chin bones, 1 non-resorbable hydroxyapatite plus mandibular alveolar ridge bone, and 1 mixed of resorbable hydroxyapatite plus human freezed dry bone. Histopathological investigation on several small speciemens taken from grafts of these different materials was performed. New bone formation, small amount of bone resorption and fibrous encapsuling tissue were observed for autogenous bone graft, but new bone formation was delayed around non-resorbable hydroxyapatite particles, and most of all grafted specimens of human freezed dry bone was replaced and encapsulated by fibrous tissues. These results showed that autogenous bone is highly recommended as graft material for sinus lift procedure. Endosseous implants were placed for 8 patients in the first group after an average period of 9.2 months of elevation, and for 2 patients in the second group at the time of elevation. One patient in the third group received a second sinus elevation to prevent maxillary sinusitis by perforating through maxillary sinus membrane following the installation. The survival rate of dental implants with sinus lift procedure was 94.1% after fabrication of prosthesis without any complication.

     

A systematic review and meta-analysis of long-term studies (five or more years) assessing maxillary sinus floor augmentation

The objective was to test the hypothesis of no difference in long-term (≥5 years) implant treatment outcomes after maxillary sinus floor augmentation (MSFA) with autogenous bone graft compared to a mixture of autogenous bone graft and bone substitutes or bone substitutes alone. A MEDLINE (PubMed), Embase, and Cochrane Library search in combination with a hand-search of relevant journals was conducted. Human studies published in English between January 1, 1990 and October 1, 2016 were included. Nine studies fulfilled the inclusion criteria. The survival of suprastructures has never been compared within the same study. The 5-year implant survival after MSFA with autogenous bone graft was 97%, compared to 95% for Bio-Oss; the reduction in vertical height of the augmented sinus was equivalent with the two treatment modalities. Non-comparative studies demonstrated high survival rates for suprastructures and implants regardless of the grafting material used. Meta-analysis revealed an overall estimated patient-based implant survival of 95% (confidence interval 0.92–0.96). High implant stability quotient values, high patient satisfaction, and limited peri-implant marginal bone loss were revealed in non-comparative studies. No long-term randomized controlled trial comparing the different treatment modalities was identified. Hence, the conclusions drawn from the results of this systematic review should be interpreted with caution.     

Immediate loading of the grafted maxillary sinus using platelet rich plasma and autogenous bone: a preliminary study with histologic and histomorphometric analysis

OBJECTIVE: The goal of this clinical study was to evaluate dental implant survival rates using the concept of a nonfunctional, immediate loading protocol with nonsplinted dental implants in the grafted maxillary sinus during a 52-week period. Random histomorphological and histomorphometric analysis was completed to evaluate the early healing effect of platelet rich plasma (PRP) and 50% autogenous bone combined with 3 different substitute graft materials. MATERIALS: Four to 8 months after grafting the sinus with PRP sprayed autogenous bone combined with 3 different substitute graft materials in a 50:50 composite ratio, 27 hydroxyapatite- coated dental implants were surgically placed in 41 patients and immediately loaded between 48 hours and 5 days later with custom titanium abutments and acrylic provisional restorations placed out of functional occlusion. Six months later, definitive ceramometal restorations were cemented on to the custom abutments. RESULTS: During a 52-week observation period, no implants were lost. Between 4 and 8 months of graft healing time, histologic and histomorphometric analysis revealed formation of new vital bone in different graft specimens ranging from 77% to 100%. CONCLUSION: The preliminary results of this clinical study indicate that immediate nonfunctional loading using PRP and 50% autogenous bone combined with different substitute graft materials is a predictable protocol in the grafted maxillary sinus as early as 4 months of postgrafting. The high implant survival rate is due to the early formation of large percentages of new vital bone as confirmed by using histologic and histomorphometric analysis.     

Maxillary sinus floor augmention with autogenous bone grafts to enable placement of SLA-surfaced implants: preliminary results after 15-40 months

This study presents preliminary results of placing SLA(R) surfaced ITI(R) implants in conjunction with maxillary sinus floor augmentations using autogenous bone. One hundred and eighty three ITI implants (SLA(R) surface) were inserted after 66 sinus floor elevation procedures in 41 consecutive patients. Forty-eight implants were placed simultaneously and 135 implants in a staged procedure with an average healing time of 4.9 months (148 days) after sinus grafting. Loading of the implants was allowed following an average time of 4.1 months (122 days). The follow-up time was 15-40 months after implant placement. Clinical follow-up consisted of single tooth and panoramic X-rays, and determination of Bleeding On Probing (BOP) and Plaque Index. One implant failed. One hundred and eleven of the inserted implants were used for fixed dentures, 20 for bar constructions, 41 for single crowns, and 11 were loaded provisionally until today. The total 2-year implant survival rate was 99.5%. Keeping the short follow-up period in mind, the encouraging results compared with previous studies, further support the findings of a positive influence of rough surfaces in grafted bone.     

Autologous bone graft to augment the maxillary sinus in conjunction with immediate endosseous implants: a retrospective study up to 5 years.

This study reports the successful use of osseointegrated implants to replace posterior teeth combined with the autogenous bone graft technique in the sinus. Preliminary data (1 to 6 years experience) of this one-stage procedure are presented. A total of 33 patients were treated--44 sinus grafts were augmented with bone from the anterior iliac crest. Reconstruction was completed with ceramic fixed partial dentures, and there was a follow-up of 3 to 80 months (mean 40.2 months) after loading. None of the 44 sinus grafts was lost. Of the 121 implants placed, eight failed, resulting in a failure rate of 6.6% and a cumulative failure rate of 6.8%. Of the 44 prostheses placed in the 44 sinuses, one failed, resulting in a prosthesis stability of 97.7%. Complications were encountered in three patients (three sinuses, eight implants); treatments were administered, symptoms subsided, and the implants integrated in two patients (two sinuses, six implants). One patient lost the two implants and the prosthesis, but the graft integrated. No other complications have since occurred. The results compare favorably with previous reports in terms of implant survival and stability. The implant survival rate approached that of implants placed in uncompromised maxillary bone.     

Postoperative tomographic assessment of veneer bone grafting with implant placement in the maxillary anterior region

Various ridge augmentation and sinus lift procedures were performed in severely resorbed alveolar crests of a maxilla to provide some volume for implant treatment. It was reported that the outcome of maxillary sinus lift procedures was evaluated with conventional tomography or computerized tomography, and that grafted bone around implants markedly progressed in resorption, particularly at the implant apex. However, veneer bone grafting with implant placement has not been evaluated after treatment with imaging techniques. Therefore, the purpose of this study was to assess veneer bone grafting after maxillary anterior implant treatment. Seven patients with a mean age of 24 years, with implants placed in the maxillary anterior region with or without autogenous veneer bone grafting were postoperatively examined using conventional tomography. On tomograms, the ratio of bone-to-implant contact and the area of bone were measured in labial bones with bone grafts, and they were compared with the values without bone grafts. In cases with bone grafting, the average ratio of bone-to-implant contact was 63.6%, whereas 81.8% was formed in cases without bone grafting. The average area of bone was 12.9 mm and 23.4 mm in patients with and without bone grafting, respectively. No significant difference was found between the implants with and without bone grafts. Resorbed labial bone was observed in the maxillary anterior region with and without veneer bone grafting.     

自体植骨上颌窦底提升同期种植体植入术近期疗效观察

目的:评价自体骨开窗式上颌窦提升术对上颌后牙区牙槽骨高度严重不足(高度4～6mm)的患者种植治疗的近期疗效。方法:对4例上颌后牙骨量不足(高度4～6mm)而需种植修复的病例,实施自体植骨的开窗式上颌窦提升术,并同期植入种植体共9枚。自体移植骨来自种植窝制备时中空钻取骨,在需做牙槽嵴修整处的牙槽骨棘取骨,如不够再用刮骨器取骨或从颏部手术取骨,将所取之骨碾碎备用。结果:术后7个月拍片,均显示骨性愈合;冠修复后行使功能18～24个月效果理想。结论:自体取骨植骨用于上颌窦提升,可扩大种植手术适应证,降低种植成本。     

Sinus floor augmentation with bovine hydroxyapatite mixed with fibrin glue and later placement of nonsubmerged implants: a retrospective study in 50 patients

PURPOSE: The aim of the present study was to evaluate retrospectively both the results of using a mixture of bovine hydroxyapatite (BHA) and fibrin glue as the only grafting material in the floor of the maxillary sinus and the outcome of nonsubmerged implants placed later. MATERIALS AND METHODS: A total of 50 consecutive patients (71 maxillary sinuses) were augmented with a mixture of BHA and fibrin glue. The grafts were allowed to heal for a mean of 8 months prior to implant placement. A total of 218 solid titanium screw-type implants were placed in a nonsubmerged fashion and allowed to heal for a mean of 10 weeks before loading (range, 10 days to 10 months). The outcome of the placed dental implants was evaluated retrospectively. RESULTS: Twelve implants were lost, giving a cumulative survival rate of 94.5% after a mean loading time of 20 months (range, 6 to 42 months). DISCUSSION: This study shows that augmentation of the maxillary sinus with a BHA/fibrin glue mixture and later placement of nonsubmerged implants with short healing times preceding functional loading can be a predictable concept. However, the use of autogenous bone and placement of submerged implants in the grafts with long healing times is routine in many clinics. This article discusses the evidence on which this protocol is based. CONCLUSION: The short-term results from this retrospective clinical study indicated that BHA/fibrin glue can be used as a grafting material without autogenous bone in the maxillary sinus to produce a high survival rate for later placement of nonsubmerged implants.     

A Prospective 1‐Year Clinical and Radiographic Study of Implants Placed after Maxillary Sinus Floor Augmentation with Synthetic Biphasic Calcium Phosphate or Deproteinized Bovine Bone

Background: The technique of using bone grafts or different biomaterials for augmentation of the maxillary sinus prior to implant placement is well accepted by clinicians. However, clinical documentation of some bone substitutes is still lacking. Purpose: This prospective study was designed to evaluate the success rate of implants placed after maxillary sinus augmentation with a novel synthetic biphasic calcium phosphate (BCP) or deproteinized bovine bone (DBB), the latter acting as control. Material and Methods: Nine edentulous patients and two partially edentulous patients with a mean age of 67 years with a bilateral need for sinus augmentation, <5 mm residual bone in the floor of the sinus and a crestal width ≥4 mm, were included in the study. After bilateral elevation of the Schneiderian membrane, all patients were randomized for augmentation with synthetic BCP in one side and DBB in the contralateral side. After 8 months of graft healing, 62 implants with an SLActive surface were placed. Implant survival, graft resorption, plaque index, bleeding on probing, sulcus bleeding index, probing pocket depth, and implant success rate were evaluated after 1 year of functional loading. Results: After a mean of 118 days, all patients received their fixed prosthetic constructions. One implant was lost in each biomaterial, giving an overall survival rate of 96.8%. Success rates for implants placed in BCP and DBB were 91.7 and 95.7%, respectively. No significant difference in marginal bone loss was found around implants placed in BCP, DBB, or residual bone, respectively. The mean graft resorption was 0.43 mm (BCP) and 0.29 mm (DBB). Conclusion: In this limited study, implant success rate was not dependent on the biomaterial used for maxillary sinus augmentation. Similar results were found after 1 year of functional loading for implants placed after sinus augmentation using BCP or DBB.     

Long-term results with different bone substitutes used for sinus floor elevation

One of the surgical procedures preceding implantation is elevation of the base of the maxillary sinus. Numerous bone substituting materials (grafts) may be used for this purpose, including autogenous bone, heterografts, xenogenous bone, and synthetic materials alone or in combination or mixed with growth factors and bone morphogenetic protein (BMP) preparations. A study of the frequencies of the failures (graft material resorption or implant loss) after sinus elevations with various graft materials or their combinations was conducted. In the 5-year period from 1996 through 2001, a follow-up investigation of 810 maxillary sinus augmentations was performed, in which the sinus elevations involved the use of autogenous bone, a calcium carbonate-coated polymer, hydroxylapatite of algal origin, calcium carbonate gel produced from coral or beta-tricalcium phosphate alone, autogenous bone mixed with these bone substitutes, or a combination of beta-tricalcium phosphate and platelet-rich plasma. The incidences of graft resorption and implant loss after the augmentations with various bone substitutes were recorded. Total resorption (disappearance) of the bone substitute material was observed in 2.7% of the cases. An essential difference was not experienced between the various bone substitutes from this aspect, with the exception of the gel-state calcium carbonate, where 40% of the grafts were resorbed. In total, 5.46% of the implants were lost; the differences between the various materials were not significant.     

Rehabilitation of Deficient Alveolar Ridges Using Titanium Grids Before and Simultaneously With Implant Placement: A Systematic Review

Background: The aim of the present study is to perform a systematic review of the literature on the use of titanium grids for implant surgery before and simultaneously with implant placement and to assess the success rate of the procedure, as well as survival and success rates of implants placed in the regenerated areas. Methods: Medline was used to identify studies in English published from 1996 to 2011. An additional hand search was performed of the relevant journals and of the bibliographies of the papers identified. Articles retrieved by two independent authors were screened using specific inclusion criteria: randomized controlled trials (RCTs), controlled clinical trials, and prospective clinical studies regarding vertical and/or horizontal regeneration of the alveolar ridge using titanium grids, in association or not with biomaterials, before and simultaneously with implant placement. Results: Six articles were selected, including a total of 79 patients, 87 titanium grids, and 141 implants. Twenty‐four implants were placed simultaneously with titanium grids, and 117 implants were inserted after a period of 4 to 9 months. Titanium grids in combination with autogenous bone were used in 43 cases, 25 in combination with a mixture of autogenous bone and bone substitutes, 14 in association with bone substitutes, five using only titanium grids. The overall success rate of the regenerative procedures was 98.86%; the overall survival and success rates of implants were 100% and 93.2%, respectively. Conclusions: The main limit of the present systematic review is the scarcity of papers with an adequate and consistent methodology regarding the data collection and analysis and the lack of RCTs and large well‐designed long‐term trials. Survival and success rates of implants placed in the areas treated with titanium grids were comparable to those of implants placed in native, non‐regenerated bone and of implants placed in bone regenerated with resorbable and non‐resorbable membranes.     

Maxillary sinus augmentation using different grafting materials and dental implants in monkeys. Evaluation of autogenous bone combined with porous hydroxyapatite.

The aim of this study was to evaluate clinically, histologically, and histometrically the use of autogenous bone combined with porous hydroxyapatite (Interpore 200®) as a grafting material for maxillary sinus augmentation procedures. In 4 adult male rhesus monkeys (Macaca mulatta) the 1st, 2nd and 3rd maxillary molars on one side of the jaws were extracted. After a healing period of 3 months. maxillary sinus augmentation procedures were performed in each monkey, and the sinuses were grafted with autogenous bone from the monkeys' tibia mixed in a 3:1 ratio with porous hydroxyapatite. At the same time. 2 pure titanium plasma-sprayed IMZB cylinder implants were immediately placed into the augmented sinuses (i.e. simultaneous implants-loaded group). After 4 months, 2 additional similar implants were placed into the previously augmented sinuses (i.e. delayed implants-loaded group). Four months later, the abutment connection was performed and all 4 implants were loaded with a gold-alloy bridge for 6 months (i.e. until sacrifice of the animals). The contralateral side of each monkey received similar treatment with the exception that the extractions were performed 7 months after those in the opposite side and that the implants were not loaded. Thus, 2 additional study groups (i.e. simultaneous implants unloaded group and delayed implants unloaded group) were obtained. Clinically, all loaded implants were stable at the day of sacrifice. Histologically, the grafted sinuses exhibited a significant amount of new bone formation. The porous hydroxyapatite granules appeared integrated with the newly formed bone. Histometric analyses revealed that delayed implant placement resulted in a greater amount of direct mineralized bone-to-implant contact in the augmented area than the simultaneous implant placement. Furthermore, the percentage of direct mineralized bone-to-implant contact was far more significant in the residual bone than in the augmented area. It was concluded that the autogenous bone/porous hydroxyapatite graft combination enhanced bone formation and mineralized bone-to-implant contact in the augmented sinuses and that the delayed implant placement may be favorable for sinus augmentation procedures.     

Implant placement immediately after the lateral approach of the trap door window procedure to create a maxillary sinus lift without bone grafting: a 2-year retrospective evaluation of 47 implants in 33 patients.

PURPOSE: The present study was undertaken to retrospectively evaluate the status of implants in patients subjected to a maxillary sinus lift and immediate implant placement without bone grafting. PATIENTS AND METHODS: Seventy-five implants were placed in 47 patients from 2000 to 2006. Lateral approach for the trap-door, open-window method for sinus lifting without placement of either autogenous bone grafts or allogeneic bone substitute was carried out. A 5-mm of the bone level was required in the alveolar ridge for all. All implants were placed synchronously with sinus lifting procedure. Patients underwent strict oral hygiene instruction, periodontal charting, presurgical/postsurgical panoramic radiographs, and postsurgical computed tomographic scan during the follow-up. The implant survival was defined when the prosthesis had been delivered and followed for 2 years without infection, pain, or more than 2-mm peri-implant bone loss. RESULTS: Thirty-three patients (23 males, 10 females) having an average age of 55 years old, with a total of 47 fixtures were followed for more than 2 years after prosthesis delivery. No patients developed sinusitis or other complications leading to loss of an implant subsequent to performance of the sinus lifting-combined immediate implant surgery. The 2-year survival of fixture was 100%. Increases in lifted sinus bone height ranged from 3 mm to 9 mm with an average of 4.5 mm. The peri-implant health was judged to be good with a peri-implant sulcus depth of 2.7 +/- 0.5 mm at 2-year follow-up. CONCLUSIONS: A good survival rate was observed in the immediate implant placement synchronously with the lateral approach for maxillary sinus lift without bone grafting.