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.     

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.     

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.     

Factors affecting the survival of implants placed in grafted maxillary sinuses: a clinical report

Many factors affect the survival rate of osseointegrated implants placed in grafted maxillary sinuses. This clinical report describes the retrospective evaluation of 60 patients with 228 implants placed in 84 grafted maxillary sinuses at the Loma Linda University School of Dentistry. The factors used to determine the survival rates of these implants were implant type, simultaneous/delayed implant placement, pretreatment bone height, oral hygiene, and cigarette smoking habits. Out of the total 228 implants, 205 (89.9%) remained in function after a mean follow-up period of 41.6 months (range 0 to 60 months). A higher failure rate was associated with the use of non-threaded implants, poor oral hygiene, and smoking. This information may facilitate treatment planning and enhance communication between the dentist and patient regarding the risk/benefit ratio and outcomes of implants placed in grafted maxillary sinuses.     

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.     

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.     

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 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.     

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 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.     

Effect of Smoking Habits on Accuracy of Implant Placement Using Mucosally Supported Stereolithographic Surgical Guides

Background: Smoking is considered as a factor for implant survival and peri‐implant bone loss of dental implants. Several studies revealed the negative effect of smoking on osseointegration and its dose‐related effect. Purpose: To evaluate the effect of smoking habits on accuracy of implant placement using mucosally supported stereolithographic surgical guides. Material and Methods: Six OsseoSpeed? implants (Astra Tech AB, Mölndal, Sweden) were inserted into the maxilla in 13 patients. Patients were excluded if they suffered from any systemic disease or if they were actually taking any kind of medication. Software (Mimics® 9.0) was used to fuse images of the virtually planned and actually placed implants, and locations and axes were compared between the nonsmoking and smoking subgroups. As the mucosal biotype could probably influence accuracy data, 12 reference points were defined within each patient to define a mean mucosal thickness value. Results: In the smoking subgroup, 36 implants were placed compared with 42 in the nonsmoking subgroup. Mean coronal deviation was 1.04 mm (range: 0.29–2.45 mm) among the smokers compared with 0.80 mm among the nonsmokers (range: 0.29–1.67 mm). At apical point, mean deviation was 1.26 mm (range: 0.39–3.01 mm) among the smokers compared with 1.02 mm among the nonsmokers (range: 0.32–2.59 mm). Mean angular deviation was 2.64° (range: 0.41–6.81°) among the smokers compared with 2.57° among the nonsmokers (range: 0.16°–8.86°). Significant differences were found when comparing global coronal and apical deviation between the smokers and the nonsmokers (p < .05). Evaluating mucosal thickness, mean value was 3.19 mm (range: 2.39–4.01 mm) among the smokers compared with 2.43 mm among the nonsmokers (range: 1.44–3.03 mm). Conclusions: Statistically significant differences were found when comparing the accuracy of dental implant placement of the smokers with the nonsmokers. Smokers have significant thicker supporting mucosal tissues compared with nonsmokers, which may explain inaccuracy due to less stability of the surgical guide or the scanning prosthesis.     

吸烟对种植体周围组织影响的临床观察

目的:分析吸烟对于种植义齿周围组织的影响。方法:选取42例种植病例分为吸烟、曾经吸烟和不吸烟3组,分别测量种植体植入时、义齿修复后1年的边缘骨变化和软组织变化情况。结果:吸烟组的改良龈沟出血指数与非吸烟组有显著性差异,吸烟组的牙周探诊深度变化与其他2组均有显著性差异,而其余各项指标均无统计学意义。结论:吸烟是导致种植义齿失败的一个危险因素,应告诫患者吸烟会导致种植修复的预后更差。     

The effect of smoking on survival and bone loss of implants with a fluoride-modified surface: a 2-year retrospective analysis of 1106 implants placed in daily practice

Aim: To compare the survival and peri‐implant bone loss of implants with a fluoride‐modified surface in smokers and nonsmokers. Materials and methods: Patient files of all patients referred for implant treatment from November 2004 to 2007 were scrutinized. All implants were placed by the same experienced surgeon (B. C.). The only inclusion criterion was a follow‐up time of at least 2 years. Implant survival and bone loss were assessed by an external calibrated examiner (S. V.) comparing digital peri‐apical radiographs taken during recall visits with the post‐operative ones. Implant success was determined according to the international success criteria ( Albrektsson et al. 1986 ). Survival of implants installed in smokers and nonsmokers was compared using the log‐rank test. Both nonparametric tests and fixed model analysis were adopted to evaluate bone loss in smokers and nonsmokers. Results: One‐thousand one‐hundred and six implants in 300 patients (186 females; 114 males) with a mean follow‐up of 31 months (SD 7.15; range 24–58) were included. Nineteen implants in 17 patients failed, resulting in an overall survival rate of 98.3% at the implant level and 94.6% at the patient level. After a follow‐up period of 2 years, the cumulative survival rates was 96.7% and 99.1% with the patient and implant as the statistical unit, respectively. Implant survival was significantly higher for nonsmokers compared with smokers (implant level P=0.025; patient level P=0.017). The overall mean bone loss was 0.34 mm (n=1076; SD 0.65; range 0–7.1). Smokers lost significantly more bone compared with nonsmokers in the maxilla (0.74 mm; SD 1.07 vs. 0.33 mm; SD 0.65; P<0.001), but not in the mandible (0.25 mm; SD 0.65 vs. 0.22 mm; SD 0.5; P=0.298). Conclusion: The present study is the first to compare peri‐implant bone loss in smokers and nonsmokers from the time of implant insertion (baseline) to at least 2 years of follow‐up. Implants with a fluoride‐modified surface demonstrated a high survival rate and limited bone loss. However, smokers are at a higher risk of experiencing implant failure and more prone to show peri‐implant bone loss in the maxilla. Whether this bone loss is predicting future biological complications remains to be evaluated.     

The relationship between cigarette smoking and dental implant failure

This paper examines the effect of tobacco use on the failure rates of dental implants. A review of 56 dental implant patients with a total of 187 endosseous dental implants, placed over a four year period, demonstrated a significant association between increased implant failure rates and cigarette smoking with failure rates of 16.6% in smokers compared to 6.9% in non-smokers. Also implant length was shown to be a significant factor with shorter implants (< or = 10 mm) being more susceptible to failure in smokers. A chi-square test was used for data analysis. Current recommendations that should be given to implant patients who smoke are included.     

Smoking and complications of endosseous dental implants

BACKGROUND: The purpose of this study was to compare the incidence of the complications and survival rate related to dental implants among smokers and non-smokers, and to evaluate the influence of smoking by analyzing data of 959 implants placed in 261 patients during the years 1995 to 1998. METHODS: Patients were divided into 3 groups: non-smokers, mild smokers (up to 10 cigarettes per day) and heavy smokers (more than 10 cigarettes per day); smokers were divided into 2 subgroups according to duration of smoking (less or more than 10 years). Complications included minor (spontaneous implant exposure), major (spontaneous implant exposure requiring surgical intervention), and implant failure. The influence of smoking was analyzed for the type of implant cover screw and immediate versus late implantation. RESULTS: The overall failure rate was 2% for non-smokers and 4% for all smokers. Minor and major complications were found in higher percentages (46%) in the smoking groups than in the non-smoking group (31%). A significantly higher incidence of complications was found among smokers who received dental implants with high cover screws (63%) compared to those who received dental implants with flat cover screws (27%). CONCLUSIONS: This study establishes a relationship between implant complications and smoking, implant type (external or internal hex), and time of implantation as significant factors. A higher incidence of complications was found in the smoking group, especially in implants that had a high cover screw. Most complications will not lead to failures. Immediate implants failed less frequently than non-immediate implants. Limiting or reducing smoking habits will decrease complications of endosseous dental implants.     

The effect of smoking on osseointegrated dental implants. Part I: implant survival

PURPOSE: Recent studies implicate smoking as a significant factor in the failure of dental implants. The purpose of this long-term retrospective study was to evaluate the survival of Br?nemark endosseous dental implants in relation to cigarette smoking. MATERIALS AND METHODS: The sample consisted of 464 consecutively treated completely and partially edentulous patients who had a total of 1852 implants placed between 1979 and 1999, and who were part of a surgical/prosthodontic prospective treatment outcomes study. The effect of cigarette smoking on implant survival in relation to the time of implant failure, gender, age, surgeon, date and site of implant placement, implant length and diameter, prosthesis design, and occlusal loading considerations was assessed in bivariate and multivariate survival analyses. RESULTS: The overall implant failure rate was 7.72%. Patients who were smokers at the time of implant surgery had a significantly higher implant failure rate (23.08%) than nonsmokers (13.33%). Multivariate survival analysis showed early implant failure to be significantly associated with smoking at the time of stage 1 surgery and late implant failure to be significantly associated with a positive smoking history. Short implants and implant placement in the maxilla were additional independent risk factors for implant failure. CONCLUSION: Cigarette smoking should not be an absolute contraindication for implant therapy; however, patients should be informed that they are at a slightly greater risk of implant failure if they smoke during the initial healing phase following implant insertion or if they have a significant smoking history.     

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.     

Impact of smoking on marginal bone loss

PURPOSE: To compare marginal implant bone loss (MBL), survival, and radiographic evidence of success of dental implants among smokers and nonsmokers. MATERIALS AND METHODS: Consecutive records of 161 patients (aged 23 to 89 years, mean 57 years) treated with a total of 646 implants between the years 1995 and 1998 were examined. Patients were divided into 3 groups: nonsmokers, moderate smokers, and heavy smokers. Tobacco exposure was calculated by cigarettes per day and by pack-years. Follow-up ranged from 1 to 7 years (mean 3.8 years). Postoperative panoramic radiographs obtained before implant exposure and annually thereafter were analyzed for MBL changes. The influence of smoking and other variables on MBL was analyzed at all implant sites. RESULTS: Generally, smokers had more MBL than nonsmokers (0.153 +/- 0.092 mm and 0.047 +/- 0.048 mm, respectively; P < .001). When each jaw was examined separately, smoking had a greater effect on MBL in the maxilla than in the mandible (0.158 +/- 0.171 mm versus 0.146 +/- 0.158 mm, respectively; P < .001). Furthermore, in the maxilla, heavy smokers had the greatest amount of MBL (0.1897 +/- 0.1825 mm), followed by moderate smokers (0.123 +/- 0.156 mm) and nonsmokers (0.0460 +/- 0.070 mm) (P < .001). In the mandible, there was no distinction between heavy and moderate smokers, and both had greater MBL than nonsmokers (P < .001). Only 3 of the 646 implants failed; the cumulative survival rate was 99.5%. Overall radiographic success rate was 93.2%. Nonsmokers had a higher radiographic success rate (97.1%) than smokers (87.8%) (P < .001). CONCLUSIONS: This study demonstrated a relationship between MBL and smoking habits. A higher incidence of MBL was found in the smoking group, and this was more pronounced in the maxilla.     

A 6-year prospective study of 620 stress-diversion surface (SDS) dental implants

A 6-year prospective study was conducted to assess the clinical success rates and crestal bone response of a dental implant system with a stress-diversion design. Mathematical modeling, digital radiography with applied isodensity, and finite element analysis were used to highlight the effect of the stress distribution design. A total of 386 hydroxyapatite-coated prototypes and 234 commercial grit-blasted external hex implants were placed in virgin bone as well as various grafted maxillary regions, with 36% of the posterior implants being immediately loaded. Prototypes achieved 96.6% survival over a 3-year period. The grit-blasted implant, placed from 2000 to 2003, showed a 95% survival rate. There were no significant changes in crestal bone levels after the first 12 months of prosthetic loading. Engineering evaluations suggested that undesirable stresses were distributed from the crest of the ridge down through the center of the implant body.     

Predictors of dental implant survival

PURPOSE: To summarize dental implant survival rates under a variety of clinical conditions and identify prognostic variables associated with implant survival. MATERIALS/METHODS: The articles reviewed in this paper were designed as retrospective cohort studies and composed of three subject cohorts having implants placed between 1992 and 2003. The prognostic variables were categorized as demographic/health status, anatomic, implant-specific, prosthetic, and perioperative/operative. The primary outcome variable was duration of implant survival. Kaplan-Meier methods were used to estimate implant survival rates. Multivariate Cox proportional hazards models were used to identify prognostic variables. RESULTS-During the study interval, 921 subjects had 2996 implants placed. Implant survival rates at one year ranged from 90.3 percent for immediate-load implants to 96.2 percent for implants inserted into grafted sinuses. The five-year survivals ranged from 87.9 percent (sinus graft cases) to 91.2 percent (all implants). Frequently cited prognostic variables included tobacco use and implant staging. Other prognostic variables identified included implant length, well size, implant coating, and timing of implant placement relative to tooth extraction. CONCLUSION: Using implants to replace missing teeth is a predictable procedure with five-year survival rates approximating 90 percent. Some of the prognostic variables identified in these studies are under the control, at least to some degree, of the clinician and may be manipulated to enhance implant survival.