Stijn Vervaeke

The Influence of Initial Soft Tissue Thickness on Peri‐Implant Bone Remodeling

AIM To elucidate the influence of initial soft tissue thickness on peri-implant bone remodeling. The research hypothesis was that implants installed in patients or at sites with thin mucosal tissues would show increased peri-implant bone loss. MATERIAL AND METHODS 79 edentulous patients were consecutively treated with two non-splinted implants supporting an overdenture in the mandible. During recall-visits, peri-implant health was determined by means of probing pocket depth and the modified plaque/bleeding index. Digital peri-apical radiographs were taken from individual implants. Bone level changes were measured from a reference point (lower border of the smooth implant collar) to the marginal bone-to-implant contact level. The linear mixed-effect model analysis was adopted to analyze the influence of clinical parameters and transmucosal abutment height on peri-implant bone loss. RESULTS 67 patients attended the 1-year and 66 the 2-year recall-visit. Mean bone level changes were 0.89 mm (SD 0.62) and 0.90 mm (SD 0.66), plaque scores 0.82 (SD 0.94) and 0.87 (SD 0.92), bleeding scores 0.46 (SD 0.68) and 0.56 (SD 0.72) and PPD 1.65 mm (SD 0.60) and 1.78 mm (SD 0.59) after 1 year and 2 years respectively. The linear mixed-effect model revealed increasing bone level changes with decreasing abutment heights. Peri-implant bone level changes were significantly higher for implants with abutments of <2 mm (1.17 mm, p < .01; 1.23 mm, p < .01), 2 mm (0.86 mm, p < .01; 1.03 mm, p < .01) or 3 mm (0.38 mm, p = .046; 0.41 mm, p = .044) compared to ≥4 mm-abutments (bone level changes set to zero as reference value) both after 1 year and 2 years and bone level changes were significantly influenced by probing pocket depth (p < .01, p < .01), but not by plaque (p = .31, p = .09) and bleeding scores (p = .30, p = .40). CONCLUSION The present study suggests that implants with lower abutments, reflecting the initial gingival thickness, lose more peri-implant bone, possibly by a re-establishment of the biological width.

A multifactorial analysis to identify predictors of implant failure and peri-implant bone loss.

OBJECTIVE To identify risk factors for failure and bone loss of implants in a large study sample on the basis of multivariate analyses. MATERIALS AND METHODS Patient files of all patients referred for implant treatment from November 2004 to December 2007 were scrutinized, and information on implant- and patient-related factors was collected. The study sample in this retrospective cohort study consisted of both partially dentate and fully edentulous patients referred for various indications. The only inclusion criterion was a follow-up of at least 2 years. Implant survival and bone loss were assessed by an external investigator (SV) comparing digital periapical radiographs taken during recall visits with the postoperative ones. Univariate and multivariate tests were adopted to identify possible risk indicators for implant failure and peri-implant bone loss. RESULTS Twenty-one of 1,320 (1.6%) implants were lost in 19 of 376 (5.1%) patients (210 female, 166 male; mean age 56, range 17-82) after a mean follow-up of 32 months (range 24-62). Based on multivariate analysis, only smoking (p = .001) and recall compliance (p = .010) had a significant influence on implant failure, with smokers more prone to failure. The overall mean bone loss was 0.36 mm (SD 0.68, range 0.00-7.10). Smoking (p = .001) and jaw of treatment (p = .001) affected peri-implant bone loss. More peri-implant bone loss was observed in smokers and in the maxilla. A clear discrepancy was found between univariate and multivariate analysis with regard to identification of risk factors. CONCLUSION Multivariate analysis demonstrated that implant-related factors did not affect the clinical outcome, but smoking was identified as a predictor for implant failure. Predictors for peri-implant bone loss were smoking and jaw of treatment.

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.

A 9‐Year Prospective Case Series Using Multivariate Analyses to Identify Predictors of Early and Late Peri‐Implant Bone Loss

PURPOSE The study aims to identify predictors of early and late peri-implant bone loss following complete implant-supported rehabilitation using multivariate analyses. MATERIALS AND METHODS Fifty patients (28 women, 22 men; mean age 58, range 35-76) in need of a complete implant-supported rehabilitation on five to eight implants were consecutively treated. Patients were reinvited for a clinical and radiographic examination after an average 9 years of function. Implant survival and peri-implant bone loss were considered the dependent variables. Multivariate analyses were adopted to identify predictors of early and late peri-implant bone loss. RESULTS In total, 39 patients were examinated. Two implants failed after 4 years of function, resulting in an overall survival rate of 99.2%. After a mean follow-up of 9 years, mean bone loss of 1.68 mm (SD 2.08, range -1.05 to 10.95) was found. The abutment height was a significant predictor of early peri-implant bone loss (1 year) (p = .024), whereas smoking (p = .046) and history of periodontitis (p = .046) affected late peri-implant bone loss. CONCLUSION Within the limits of this study, it can be concluded that initial bone remodeling was affected by soft tissue thickness as reflected by the height of the abutment, whereas smoking and history of periodontitis affected long-term peri-implant bone stability.

The effect of implant surface modifications on survival and bone loss of immediately loaded implants in the edentulous mandible.

PURPOSE To compare the 2-year survival and peri-implant bone loss of implants with and without a fluoride modification under immediate loading conditions in completely edentulous mandibles. MATERIALS AND METHODS A total of 125 Osseospeed implants (test group) were placed in 25 patients requiring a fixed rehabilitation. Implants were loaded immediately (baseline) with a provisional screw-retained prosthesis. Implant survival and bone level changes were analyzed at 3, 12, and 24 months. Results were compared with the outcome of 25 previously treated patients with immediately loaded TiOblast implants using the same treatment protocol (control group). RESULTS Implant survival was 100% for both groups. After 3, 12, and 24 months, the mean bone loss for the control group was 0.60, 0.81, and 0.84 mm on the patient level and 0.60, 0.80, and 0.86 mm on the implant level. For the test group, a mean bone loss of 0.14, 0.11, and 0.11 mm was for the patient; and 0.14, 0.11, and 0.11 mm with the implant as statistical unit after 3, 12, and 24 months, respectively. No statistically significant differences were observed comparing peri-implant bone loss at 3 months with 12 and 24 months in both groups, but the control group showed more peri-implant bone loss compared with the test-group (P < .001). Moreover, the control group showed an increasing interquartile range over time, suggesting that not every implant is reaching steady-state bone levels. CONCLUSIONS Immediate loading of implants placed in the completely edentulous mandible is a successful treatment option with high survival rates and limited bone loss after 2 years. However, initial crestal bone preservation significantly benefits from fluoride modification.

Implant surface roughness and patient factors on long‐term peri‐implant bone loss

Dental implant placement is a common treatment procedure in current dental practice. High implant survival rates as well as limited peri-implant bone loss has been achieved over the past decades due to continuous modifications of implant design and surface topography. Since the turn of the millennium, implant surface modifications have focused on stronger and faster bone healing. This has not only yielded higher implant survival rates but also allowed modifications in surgical as well as prosthetic treatment protocols such as immediate implant placement and immediate loading. Stable crestal bone levels have been considered a key factor in implant success because it is paramount for long-term survival, aesthetics as well as peri-implant health. Especially during the past decade, clinicians and researchers have paid much attention to peri-implant health and more specifically to the incidence of bone loss. This could furthermore increase the risk for peri-implantitis, the latter often diagnosed as ongoing bone loss and pocket formation beyond the normal biological range in the presence of purulence or bleeding on probing. Information on the effect of surface topography on bone loss or peri-implantitis, a disease process that is to be evaluated in the long-term, is also scarce. Therefore, the current narrative review discusses whether long-term peri-implant bone loss beyond physiological bone adaptation is affected by the surface roughness of dental implants. Based on comparative studies, evaluating implants with comparable design but different surface roughness, it can be concluded that average peri-implant bone loss around the moderately rough and minimally rough surfaces is less than around rough surfaces. However, due to the multifactorial cause for bone loss the clinical impact of surface roughness alone on bone loss and peri-implantitis risk seems rather limited and of minimal clinical importance. Furthermore, there is growing evidence that certain patient factors, such as a history of periodontal disease and smoking, lead to more peri-implant bone loss.

Clinical and radiographic outcome of implants placed using stereolithographic guided surgery: a prospective monocenter study.

PURPOSE The number of clinical reports giving detailed information on clinical outcomes with guided surgery is rather scarce despite its large-scale introduction over the last decade. The aim of this report was to determine implant survival and success in terms of peri-implant bone loss and evaluate whether smoking affects the outcome. MATERIALS AND METHODS A total of 26 cases with a partially or totally edentulous maxilla were selected for implant treatment using the Facilitate software system (Astra Tech). In totally edentulous cases, six fluoride-modified OsseoSpeed implants (Astra Tech) were inserted. Immediately after implantation, abutments were screwed onto the implants. Within 8 hours, a provisional screw-retained fiber-reinforced acrylic fixed dental prosthesis was screwed on the abutments. For the partial cases, the surgical guide rested on the remaining teeth and implants were not immediately loaded. RESULTS In total 13 out of 114 implants were lost within 12 months after surgery, resulting in 88.6% survival at 1 year. Twelve of those failures occurred in smokers, leading to 69.2% implant survival compared to 98.7% in nonsmokers. Implants were lost in 7 out of 26 (26.9%) patients; only 1 out of 17 nonsmokers (5.9%) compared to 6 out of 9 (66.7%) smokers lost one or more implants. In total, 38.5% of the subjects with a full immediately loaded fixed dental prosthesis experienced implant failures compared with 15.4% of the partially delayed loaded cases. The overall mean bone loss based on all implants was 0.47 mm (SD, 0.94). Mean bone loss was 0.36 mm for nonsmokers and 0.62 mm for smokers. CONCLUSIONS On the basis of the current case control study, it is tempting to suggest that smoking is an exclusion factor when placing implants using stereolithographic guided surgery in conjunction with immediate loading. There is still not enough scientific evidence to show if this method is as safe and predictable as the traditional method.

Immediate loading of implants in the maxilla: survival and bone loss after at least 2 years in function

PURPOSE To compare survival and peri-implant bone loss around immediately loaded surface-enhanced implants in the maxilla supporting single crowns (SCs), fixed partial dentures (FPDs), and fixed full-arch dentures (FFDs). MATERIALS AND METHODS The study included all subjects referred for implant treatment in the maxilla followed by immediate loading between November 2004 and 2007 with at least 2 years of follow-up. Smokers were excluded. Implant survival and bone loss were assessed by a calibrated external examiner who compared digital periapical radiographs taken during recall visits with baseline radiographs (day of loading = day after implant placement). An implant was considered successful when bone loss did not exceed 1 mm. Survival of implants supporting SCs, FPDs, and FFDs was compared using the log-rank test. A linear mixed-effect model analysis was used to evaluate bone loss because of clustering of implants in patients. RESULTS Three hundred six implants were placed in 55 patients (31 women, 24 men; mean age, 57.5 ± 11.4 years; range, 19 to 77 years) and followed for a mean of 35 ± 10.2 months (range, 24 to 58 months). One implant failed, resulting in an overall survival rate of 99.7% on the implant level and 98.2% on the patient level. No statistically significant differences were observed in the survival rates for SCs (100%), FPDs (98%), and FFDs (100%). The overall mean bone loss was 0.27 ± 0.37 mm (range, 0.00 to 2.55 mm) and was not influenced by the prosthetic reconstruction. CONCLUSION Immediate loading of fluoride-modified implants in the maxilla is a predictable and reliable treatment option with high survival rates and limited peri-implant bone loss after 2 years. No statistically significant differences were found between implants supporting SCs, FPDs, and FFDs.

Clinical and Radiographic Comparison between Platform-Shifted and Nonplatform-Shifted Implant : A One-Year Prospective Study

BACKGROUND Developments in implant hardware and biologic understanding improved treatment predictability in terms of implant survival. Current research focuses on accelerated loading protocols and crestal bone preservation. PURPOSE This prospective, monocenter study analyzed the clinical and radiographic outcome of a novel parallel-walled implant, with and without platform shift. MATERIALS AND METHODS Forty-eight consecutively treated patients (30 women, 18 men) with crowns/bridges supported by 115 implants were included. Eighty-three percent of implants were nonocclusal, immediately loaded, and 17% were subjected to one-stage surgery and delayed loading after 10 weeks; 39.1% were of diameter 5.0 mm, enabling platform shifting with a 4.0 mm-wide prosthetic component; 60.9% were of diameter 4.0 mm with a 4.0 mm component. Radiographic crestal bone levels were assessed at baseline and 1 year. A multivariate statistical analysis was performed to determine factors affecting crestal bone loss after 1 year. RESULTS All implants survived and mean marginal bone loss was 0.73 mm (SD: 0.13; range: -0.60 to 5.0 mm). There was a statistically significant difference between platform-shifted (0.63 mm; SD: 0.18) and nonplatform-shifted (1.02 mm; SD: 0.14) implants. Implants in abundant bone volume lost significant less crestal bone (0.45 mm; SD: 0.14) compared with implants in small volume (1.20 mm; SD: 0.21). Implant diameter, loading time, anatomical position, smoking, and bone quality did not affect crestal bone loss. CONCLUSION After 1 year of loading, both implant-prosthetic features yield a high survival and limited crestal bone loss. Crestal bone loss is minimized using platform-shifted implants placed in sufficiently voluminous bone. To limit the crestal bone loss, an adopted implant diameter with platform shifting should be considered.

Ten‐year follow‐up of dental implants used for immediate loading in the edentulous mandible: A prospective clinical study

PURPOSE The purpose of this study is to evaluate the 10-year outcome of 25 patients with immediate loading in the edentulous mandible. MATERIAL AND METHODS Twenty-five patients were consecutively treated with 5 immediately loaded fluoride-modified implants in the edentulous mandible. Implant survival and bone loss were evaluated by an external researcher comparing digital periapical radiographs taken during recall visits with baseline (at implant insertion). Statistical descriptive analysis and nonparametric tests were performed using SPSS v23, multilevel analysis was performed by means of R version 3.1.0. to identify risk factors for bone loss. RESULTS Twenty-one patients (8 males, 13 females, mean age 68.4, range 49-84) responded to the 10-year recall invitation. No implants were lost during follow-up, resulting in a 100% survival rate. After 10 years, bleeding on probing and plaque were present at 49.5% and 67.6% of the sites, respectively. The mean pocket probing depth was 3.77 mm (SD 0.73, range 3.0-6.83). Bone loss on implant level after 3, 12, 24, and 120 months was 0.16 mm (SD 0.33, range 0-1.75), 0.14 mm (SD 0.24, range 0-1.05), 0.17 mm (SD 0.27, range 0-1.5), and 0.49 mm (SD 1.08, range 0-7.8). Five implants were identified with or at risk for progressive bone loss. Forty-seven percent of the implants did not show any bone loss after 10 years in function and 87% lost less than 1 mm. Multilevel statistical analysis identified 2-year bone loss as a predictor for bone loss after 10 years of function. CONCLUSION Immediate loading of 5 fluoride-modified dental implants with a fixed prosthetic rehabilitation is a predictable and reliable treatment in the edentulous mandible, based on a 100% implant survival and limited peri-implant bone loss. Implants used for immediate loading in the edentulous mandible who are showing early bone loss may be at higher risk to develop peri-implantitis.