Effects of smoking on implant success in grafted maxillary sinuses.

STATEMENT OF THE PROBLEM: Cigarette smoking has been identified as a significant risk factor for dental implant treatment. PURPOSE: This retrospective study evaluated the effect of smoking and the amount of cigarette consumption on the success rates of the implants placed in grafted maxillary sinuses. MATERIAL AND METHODS: Sixty patients (16 smokers and 44 nonsmokers) were evaluated for the effects of smoking on osseointegrated implants placed in 84 grafted maxillary sinuses that contained a total of 228 endosseous root-form implants. Seventy implants were placed in 26 maxillary sinuses in smokers, whereas 158 implants were placed in 58 sinuses in nonsmokers. The number of implant failures and the amount of cigarette consumption were recorded. RESULTS: Of the 228 implants, 205 (89.9%) remained in function, after a mean follow-up period of 41.6 months (2 to 60 months). There was a significantly higher cumulative implant success rate in nonsmokers (82.7%) than in smokers (65.3%) (P =.027). Overall cumulative implant success rate was 76%. There was no correlation between implant failures and the amount of cigarette consumption (P >.99). CONCLUSION: Within the limitations of this study, cigarette smoking appeared to be detrimental to the success of osseointegrated implants in grafted maxillary sinuses regardless of the amount of cigarette consumption.     

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.     

The effect of cigarette smoking and native bone height on dental implants placed immediately in sinuses grafted by hydraulic condensation

The purpose of this study was to determine the effect of cigarette smoking and residual native bone height on the survival of dental implants placed immediately in grafted sinuses. In this retrospective study, 334 subject records were screened, and 75 subjects (155 implants) were included. Data collection based on treatment notes and radiographs included age, sex, smoking status, sinus floor bone height, dental implant information, and implant survival. The survival rates of implants for nonsmokers and smokers at stage-two surgery were 93% and 84%, respectively. After 12 months of functional loading, the survival rates of implants for nonsmokers and smokers were 87% (81 of 93) and 79% (49 of 62), respectively (P < .000). Analysis revealed that the effect of smoking on implant survival is significant when the preoperative bone height is less than 4 mm, with an 82.4% implant survival rate in nonsmokers compared to 60% in smokers (P < .05). Smoking should be considered as a high risk factor when implants are placed immediately in grafted sinuses, particularly in areas of limited bone height.     

Implant-supported maxillary overdentures retained with milled bars: maxillary anterior versus maxillary posterior concept--a retrospective study

PURPOSE: The aim of the present retrospective investigation was to evaluate implant-supported maxillary overdentures using either anterior (group 1) or posterior (group 2) maxillary implant placement. MATERIAL AND METHODS: Maxillary overdentures were planned with support by either 4 implants placed in the maxillary anterior region (group 1) or 6 to 8 implants placed in augmented maxillary posterior regions (group 2, bilateral sinus augmentation) and anchored either on an anterior or on 2 bilaterally placed milled bars. Cumulative implant survival rate, peri-implant conditions (marginal bone loss, pocket depth, Plaque Index, Gingival Index, Bleeding Index, and Calculus Index) and the incidence and type of prosthodontic maintenance were assessed and compared for the 2 groups. In addition, the cumulative survival rate for implants placed in grafted regions was compared with that of implants placed in nongrafted regions. RESULTS: Thirty-four patients (16 for group 1 and 18 for group 2) with 179 implants were available for follow-up examination after a mean period of 42.1 +/- 20.1 months. Four initially placed implants failed to osseointegrate and were replaced, but no further losses were seen during the loading period, for a 5-year cumulative implant survival rate of 978%. No differences in implant survival rates were seen between either the group-1 (98.4%) and group-2 (97.4%) concepts or nongrafted (98.0%) and grafted (97.5%) implants. The peri-implant parameters showed a healthy soft tissue, good oral hygiene, and an acceptable degree of peri-implant marginal bone loss. The rigid fixation of all overdentures was associated with a low incidence of prosthodontic maintenance, without any significant differences between the 2 groups. CONCLUSIONS: In well-planned overdenture treatment programs, a high survival rate and excellent peri-implant conditions can be achieved for implants placed in the anterior or posterior maxilla. Rigid anchorage of maxillary overdentures either on an extended anterior milled bar or on 2 bilateral posterior milled bars provides for a low incidence of prosthodontic maintenance.     

2种手术入路上颌窦底提升同期种植失败原因和并发症分析

目的:探讨经侧壁或牙槽嵴入路上颌窦底提升术对种植体生存率的影响,分析失败原因和并发症.方法:采用回顾性队列研究,分析2000-2015年在合肥市口腔医院口腔颌面外科就诊、由同一名医师完成上颌窦底提升同期种植的患者.主要预测变量是经侧壁入路上颌窦底提升术和经牙槽嵴入路上颌窦底提升术,混杂变量是性别、年龄、吸烟史、糖尿病史...     

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.     

Effects of smoking on the outcome of implant treatment: a literature review.

STATEMENT OF PROBLEM: The use of osseointegrated implants as a foundation for the prosthetic replacement of missing teeth has become widespread in the last decade. Owing to the remarkable success of dental implants, there has been growing interest in identifying the factors associated with implant failure. Given the well-documented deleterious effect of smoking on wound healing after tooth extraction and its association with poor quality bone and periodontal disease, a negative effect of tobacco use on implant success is to be expected. PURPOSE: To establish the relationship between smoking and implant-related surgical procedures (i.e, sinus lift procedures, bone grafts and dental implants), including the incidence of complications related to these procedures and the long-term survival and success rates of dental implants among smokers and nonsmokers based on relevant literature.MATERIALS AND METHODS: Relevant clinical studies published in English between 1990 and 2006 were reviewed. The articles were located through Medline and, manually, through the references of peer-reviewed literature. This was supplemented with a hand search of selected dental journals and text books.RESULTS: The majority of the past and current literature implicates smoking as one of the prominent risk factors affecting the success rate of dental implants with only a handful of studies failing to establish a connection. Most of the studies report the failure rate of implants in smokers as being more than twice that in nonsmokers. These findings are difficult to ignore. There is a statistically significant difference between smokers and nonsmokers in the failure rates of dental implants. Smoking also has a strong influence on the complication rates of implants: it causes significantly more marginal bone loss after implant placement, it increases the incidence of peri-implantitis and affects the success rates of bone grafts. The failure rate of implants placed in grafted maxillary sinuses of smokers is again more than twice that seen in nonsmokers.Conclusion: Smokers have higher failure rates and complications following dental implantation and implant-related surgical procedures. The failure rate of implants placed in grafted maxillary sinuses of smokers is more than twice that seen in nonsmokers.     

Maxillary sinus grafting with anorganic bovine bone: a clinical report of long-term results

PURPOSE: The aim of the present retrospective study was to evaluate the survival rate of titanium plasma spray-coated cylindric and machined screw-type implants placed in sinuses grafted with anorganic bovine bone mixed with demineralized freeze-dried bone allograft (DFDBA) or with anorganic bovine bone alone. MATERIALS AND METHODS: The patients included in this study were treated with a 1- or 2-stage technique, according to the volume of residual bone. This determined the possibility of primary stabilization and the duration of the treatment, which was 9 or 12 months, respectively. RESULTS: The overall implant survival rate was 94.5% after a mean functioning period of 6.5 +/- 1.9 years. The Implant survival rate was better in sinuses grafted with anorganic bovine bone alone than with a mixture of anorganic bovine bone with DFDBA (96.8% versus 90%). The implant survival rate was similar for cylindric and screw-type implants in sinuses grafted with anorganic bovine bone alone. DISCUSSION: Because of the good bone quality, the implant survival rate was similar for cylindric and screw-type implants in sinuses grafted with anorganic bovine bone. CONCLUSION: Anorganic bovine bone used alone appears to be a suitable material for sinus floor augmentation.     

Systematic review of survival rates for implants placed in the grafted maxillary sinus

Based on a systematic review of the literature from 1986 to 2002, this study sought to determine the survival rate of root-form dental implants placed in the grafted maxillary sinus. Secondary goals were to determine the effects of graft material, implant surface characteristics, and simultaneous versus delayed placement on survival rate. A search of the main electronic databases was performed in addition to a hand search of the most relevant journals. All relevant articles were screened according to specific inclusion criteria. Selected papers were reviewed for data extraction. The search yielded 252 articles applicable to sinus grafts associated with implant treatment. Of these, 39 met the inclusion criteria for qualitative data analysis. Only 3 of the articles were randomized controlled trials. The overall implant survival rate for the 39 included studies was 91.49%. The database included 6,913 implants placed in 2,046 subjects with loaded follow-up time ranging from 12 to 75 months. Implant survival was 87.70% with grafts of 100% autogenous bone, 94.88% when combining autogenous bone with various bone substitutes, and 95.98% with bone grafts consisting of bone substitutes alone. The survival rate for implants having smooth and rough surfaces was 85.64% and 95.98%, respectively. Simultaneous and delayed procedures displayed similar survival rates of 92.17% and 92.93%, respectively. When implants are placed in grafted maxillary sinuses, the performance of rough implants is superior to that of smooth implants. Bone-substitute materials are as effective as autogenous bone when used alone or in combination with autogenous bone. Studies using a split-mouth design with one variable are needed to further validate the findings.     

Maxillary sinus augmentation using a peptide-modified graft material in three mixtures: a prospective human case series of histologic and histomorphometric results

This prospective study assessed vital bone quality and quantity after grafting maxillary sinuses with anorganic bone mineral containing a cell binding peptide (ABM/P-15) in combination with DFDBA (Mix I), hydrogel/ABM/P-15 (Mix II), or PRP (Mix III). Fifteen maxillary sinuses in 12 patients were grafted with the ABM/P-15 mixtures and after 4 to 5 months, cores were taken and analyzed histologically and histomorphometrically. Fifty-nine screw-type implants were placed. Mixes containing a spacer material (Mix I and II) produced greater average vital bone, more mature bone, and more interconnected bone bridges from the cortical (oral) end to the most apical portion, compared to a mix that lacked a spacer material (Mix III). None of the 59 implants failed with any graft material up to 5 months following implant placement. The study demonstrates that new trabecular bone is formed after grafting ABM/P-15 in the sinus floor; that more vital bone is formed when ABM/P-15 is mixed with a spacer material than without; and that implants can be successfully placed.     

Three-year analysis of tapered screw vent implants placed into maxillary sinuses grafted with mineralized bone allograft

With an increase in the number of patients presenting for dental implant treatment, it is becoming more common for clinicians to encounter inadequate bone volume. Several surgical techniques have been advocated for placing dental implants in the posterior maxilla, including the lateral window sinus elevation technique. This article reports the results of implants placed into maxillary sinuses grafted with particulate mineralized cancellous bone allograft alone or in combination with resorbable hydroxyapatite over a 3-year period. A total of 56 sinuses were grafted, and 136 dental implants were placed into the grafted sites after a 4- to 8-month healing period. All reentries revealed a bony hard structure acceptable for osteotomy preparation. Of these implants, 124 have been restored with fixed prosthesis and 12 with removable overdentures for a total of 136 loaded implants. A total of 3 implants required removal (failure) resulting in a 97.7% implant success rate (2.3% failure rate). A conclusion was made that mineralized human allograft, placed into lateral window sinus elevations, is a clinically predicable method acceptable for implant placement and restoration.     

Survival of cylindrical implants in composite grafted maxillary sinuses

Purpose: This retrospective study investigated the survival of dental implants placed in the maxilla after composite grafting of the sinus and an average of 55 months of loading.Patients and Methods: Maxillary sinuses of 88 patients were grafted with autogenous cancellous bone combined with dense hydroxyapatite particles. After an average healing period of 3.4 months, hydroxyapatite-coated titanium endosseous implants were placed. A total of 388 implants were placed in grafted sinus floors, and 82 were placed in onlay grafted nonsinus position in the canine region. The implants were loaded with overdentures and fixed bridges 4 months (mean) after implantation, with a follow-up for a mean of 55 months.Results: The cumulative implant survival was calculated according to the Kaplan-Meier method. Implant survival from the time of loading was 89% in full reconstructed cases and 90% in partially edentulous cases. The overall cumulative implant survival rate, including the loss in the surgical stage, was 82%.Conclusion: Implant loss in composite grafted maxillae after 70 months of follow-up was similar to loss in nongrafted maxillae.     

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.     

Dental implants placed in grafted maxillary sinuses: a retrospective analysis of clinical outcome according to the initial clinical situation and a proposal of defect classification

Objective of the study: To present a classification of maxillary defects necessitating sinus floor elevation procedures (SFEPs) with two objectives: (a) to propose a standardization of surgical procedures according to initial type of atrophy and (b) to allow the evaluation of the success/survival rates of implants placed in the grafted areas according to the initial situation. Materials and methods: Nine‐hundred and fifty‐two consecutive SFEP were performed on 692 patients. Initial defects were classified according to a new classification, which considered not only residual bone height below the sinus but also the width of the alveolar crest and horizontal/vertical intermaxillary relationship. Results were evaluated according to the different classes. The sinuses were grafted with autogenous bone taken from intra‐oral or extra‐oral sites: 579 SFEP were associated with vertical and/or horizontal onlay grafts to correct concomitant alveolar ridge deficits. A total of 2037 implants were inserted into the grafted sinuses either immediately or 4–6 months later. Three to 6 months afterwards, implants were loaded. The mean follow‐up was 59 months (range: 12–144 months). Results: The success rate of the reconstructive procedures varied between 93.2% and 100%, according to class of atrophy; the overall survival and success rates of implants were 95.8% and 92.5%, respectively, whereas the survival and success rates according to class of atrophy varied between 90% and 97.6%, and between 85.4% and 95.5%, respectively. Lower success rates were found in classes presenting with more severe atrophy. Conclusion: The results obtained demonstrated that sinus floor elevation, alone or in association with reconstructive procedures with autogenous bone grafts, is a reliable procedure to allow implant placement in atrophic edentulous maxillae, irrespective of the initial clinical situation. However, it must be underlined that the success rates of reconstructive procedures and implants differ according to class of atrophy, showing lower success rates in classes presenting with more severe atrophy.     

Private practice results of screw-type tapered implants: survival and evaluation of risk factors

PURPOSE: The aims of this study were to examine the long-term survival and the prosthetic treatment outcome of screw-type, tapered implants placed in a private practice setting and to explore potential risk factors of implant failures. MATERIALS AND METHODS: In this retrospective analysis of patients treated with endosseous screw-type tapered implants, data relative to implant placement and failure, implant length, location, prosthetic treatment, medical history, smoking habits, and oral health behavior were gathered by chart review and questionnaire. An oral examination was also conducted. Cumulative survival rates were estimated through Kaplan-Meier methods. Comparisons between subgroups of patients were made using the log-rank statistical test. The association between several factors and implant failures was analyzed using Cox regression analyses (random and dependent models). Differences were considered significant when P < .05. RESULTS: The survival rate of 663 implants placed in 159 patients (65 men, 94 women; 80.7% of 197 eligible patients) was 91.8% after 120 months. Mandibular implants had a higher survival rate than maxillary implants (96% versus 89%, P = .011). The failure rates for implants were 15.0% among current smokers, 9.6% among former smokers, and 3.6% among nonsmokers. The differences between nonsmokers, former smokers, and current smokers were significant (nonsmokers versus former smokers: P = .036, nonsmokers versus current smokers: P < .001, former smokers versus current smokers: P = .003). Only number of years of smoking was significantly associated with an increased risk of implant failures (P = .036 using dependent estimation; P = .004 using independent estimation). The HR increased to 6.6 for patients who had smoked for 45 years. Loosening of prosthetic components were rare (n=12). No fractures of screws or implants were found. DISCUSSION: Higher failure rates for former smokers and a dose-response effect between duration of smoking and implant failure rates suggested that permanent tissue damage from smoking may occur in addition to immediate local and systemic effects. The frequency of prosthetic complications was comparable to other studies. CONCLUSIONS: Screw-type tapered implants placed in a private dental office demonstrated a cumulative survival rate of 91.8%. The relative risk of implant failure increased with the duration of smoking.     

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.     

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.     

Survival Rate for Implants Placed in the Posterior Maxilla With and Without Sinus Augmentation: A Comparative Cohort Study

Background: The reduced bone height and proximity of the maxillary sinus are the most common limitations for placement of dental implants in the posterior maxilla. Reconstruction of the atrophic posterior maxilla can be performed with a sinus augmentation procedure. The aim of this cohort study is to compare the survival rate of implants placed in augmented sinus to implants placed in native bone in the posterior maxilla. Methods: This study was designed as a prospective cohort study and included consecutively treated patients. Patients who required the sinus augmentation (test group) were treated according to the two‐stage technique. Patients were scheduled for follow‐up evaluation at 3, 6, and 12 months after implant placement and then every 6 months for ≤6 years. Results: One hundred and five patients with 393 implants were enrolled in the study. Two hundred and one implants were placed after preliminary sinus floor grafting in 41 patients. The control group contained 64 patients with 192 implants that were placed in pristine bone of the posterior maxilla. The cumulative implant survival rates were 86.1% and 96.4%, respectively. The difference between the two groups was highly significant (P <0.005). Conclusions: These findings show that implants placed in augmented sinuses had a lower survival rate compared to implants placed in pristine bone. All the implant failures in the augmented sinuses occurred before the prosthetic rehabilitation. Moreover, it should be considered that most of the failures were observed in few patients, thus suggesting cluster behavior.     

Maxillary sinus augmentation using different grafting materials and dental implants in monkeys

The aim of this study was to evaluate clinically, histologically and histometrically the use of anorganic bovine bone matrix (i.e. Bio-oss®) as a grafting material for maxillary sinus augmentation procedures. In 4 adult male rhesus monkeys (i.e. Mucaca mulattu) the 1st 2nd and 3rd maxillary molars on one side of the jaws were extracted. The remaining bone between the alveolar crest and the bottom of the sinus was then reduced to 3–4 mm. After 3 months, maxillary sinus augmentation procedures were performed on one side of the jaws in each monkey and the sinuses were grafted with the bovine bone matrix. At that time, 2 IMZ pure titanium plasma coated implants were immediately placed into the augmented sinuses (i.e. simultaneous implants-loaded group). After 4 months, 2 additional similar implants were placed into these 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 the same treatment with the exception that the extractions were performed 7 months after those in the opposite side and that the implants in this side 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 significant bone formation with integration of the bovine bone matrix particles to the new bone. Direct mineralized bone-to-implant contact was greater for the delayed implant placement groups than for the implants installed simultaneously with the sinus augmentation. Furthermore, the percentage of direct mineralized bone-to-implant contact was greater in the residual bone than in the augmented area. It was concluded that the anorganic bovine bone matrix facilitated bone formation and implant osseointegration in the augmented sinuses and that the delayed implant placement in combination with the sinus augmentation procedure seemed to be preferable.