Early peri-implant bone loss as a predictor for peri-implantitis: A 10-year prospective cohort study.

PURPOSE: To evaluate the effect of early bone loss (EBL), on long-term bone stability and future peri-implantitis development. MATERIALS AND METHODS: Patients referred for implant placement between 2005 and 2009 were consecutively treated and followed for 10 years. After 10 years, patients were invited for a scientific diagnostic visit to evaluate implant survival and bone loss. Bone level changes were compared with baseline. Non-parametric testing was performed in cross-tabs (Pearson Chi-square and Fishers's exact test). Kaplan-Meier-estimated survival curves were plotted for different thresholds for EBL at different timepoints. Generalized linear mixed models with binomial distribution and logit link for peri-implantitis were fitted. An adjusted logistic mixed model was made to evaluate peri-implantitis, in relation with smoking status, history of periodontitis, and EBL > 0.5 mm. RESULTS: Four hundred and seven patients (mean age of 64.86 years [range 28-92, SD 10.11]), with 1482 implants, responded to the 10-year recall invitation. After an average follow-up time of 10.66 years (range 10-14, SD 0.87), implant survival was 94.74%. Mean crestal bone loss after 10 years was 0.81 mm (SD 1.58, range 0.00-17.00). One hundred and seventy five implants in 76 patients had peri-implantitis (11.8% on implant level, 18.7% on patient level). EBL of 0.5, 1, and 2 mm were significant predictors for peri-implantitis and implant loss after 10 years. Implants with EBL ≥0.5 mm during the first year of function showed a 5.43 times higher odds for future peri-implantitis development. Probability in developing peri-implantitis was 52.06% when smoking, Periodontal history and EBL of >0.5 mm was combined. CONCLUSION: The present study suggests that EBL is a predictor for long-term peri-implant pathology, with a significant higher risk for peri-implantitis when early bone loss exceeds the thresholds of 0.5 and 1 mm, especially when additional risk factors such as smoking or susceptibility for periodontal disease prior to implant treatment are present. Clinical trial registration number B670201524796.

The Long-Term Effect of Smoking on 10 Years' Survival and Success of Dental Implants: A Prospective Analysis of 453 Implants in a Non-University Setting.

BACKGROUND: The purpose of this study was to compare the survival and peri-implant bone loss of implants with a fluoride-modified surface in smokers and non-smokers. MATERIAL AND METHODS: All patients referred for implant treatment between November 2004 and 2007 were scrutinized. All implants were placed by the same surgeon (B.C.). The single inclusion criterion was a follow-up time of at least 10 years. Implant survival, health, and bone loss were evaluated by an external calibrated examiner (S.W.) during recall visits. Radiographs taken at recall visits were compared with the post-surgical ones. Implant success was based on two arbitrarily chosen success criteria for bone loss (≤1 mm and ≤2 mm bone loss after 10 years). Implant survival in smokers and non-smokers was compared using the log-rank test. Both non-parametric tests and fixed model analysis were used to assess bone loss in both groups. RESULTS: A total of 453 implants in 121 patients were included for survival analysis, and 397 implants in 121 patients were included for peri-implant bone-loss analysis. After a mean follow-up time of 11.38 years (SD 0.78; range 10.00-13.65), 33 implants out of 453 initially placed had failed in 21 patients, giving an overall survival rate of 92.7% and 82.6% on the implant and patient level, respectively. Cumulative 10 years' survival rate was 81% on the patient level and 91% on the implant level. The hazard of implant loss in the maxilla was 5.64 times higher in smokers compared to non-smokers (p = 0.003). The hazard of implant loss for implants of non-smokers was 2.92 times higher in the mandible compared to the maxilla (p = 0.01). The overall mean bone loss was 0.97 mm (SD 1.79, range 0-17) at the implant level and 0.90 mm (SD 1.39, range 0-7.85) at the patient level. Smokers lost significantly more bone compared to non-smokers in the maxilla (p = 0.024) but not in the mandible. Only the maxilla showed a significant difference in the probability of implant success between smokers and non-smokers (≤1 mm criterion p = 0.003, ≤2 mm criterion p = 0.007). Taking jaw into account, implants in smokers experienced a 2.6 higher risk of developing peri-implantitis compared to non-smokers (p = 0.053). CONCLUSION: Dental implants with a fluoride-modified surface provided a high 10 years' survival with limited bone loss. Smokers were, however, more prone to peri-implant bone loss and experienced a higher rate of implant failure, especially in the upper jaw. The overall bone loss over time was significantly higher in smoking patients, which might be suggestive for a higher peri-implantitis risk. Hence, smoking cessation should be advised and maintained after implant placement from the perspective of peri-implant disease prevention.

Relationship between trabecular bone architecture and early dental implant failure in the posterior region of the mandible.

OBJECTIVE: To investigate the relationship between preoperative trabecular bone structure and implant outcome based on bone morphometric bone parameters from CBCT scans. MATERIALS AND METHODS: Twenty consecutive cases with early implant failure in the posterior region of the mandible were matched with 20 control patients with a successful implant osseointegration selected. All patients had taken a preoperative CBCT image according to a standardized acquisition protocol. On these CBCT scans, the trabecular bone of each implantation site was selected and segmented, after which 3D morphometric bone parameters were calculated and used in a cluster analysis to objectively differentiate trabecular bone patterns. Fisher's exact test was used to determine whether there is a significant association between trabecular pattern and implant outcome. RESULTS: A sparse, intermediate, and dense trabecular bone pattern was distinguished by cluster analysis. The relationship between the trabecular bone pattern and early implant failure was significant (z = 9.6; p < .05). Early implant failure was more likely to occur in the sparse bone types, while implant survival was associated with intermediate bone types. CONCLUSION: Prior to implant placement, attention should be given to extreme deviations in trabecular structure at the planned implant sites. Very sparse or very dense bone should be carefully evaluated at the potential implant site, while intermediate bone types seem favorable for implant survival.

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.

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.

On Speech Problems with Fixed Restorations on Implants in the Edentulous Maxilla: Introduction of a Novel Management Concept.

BACKGROUND: Little attention has been paid to the effect of implant restorations on speech. PURPOSE: The aim of this study was threefold: (1) to find out if speech problems occur after inserting a fixed provisional restoration in the edentulous maxilla; (2) to explore speech adaptation in case articulation problems arise after rehabilitation; and (3) to describe the effect of changing the shape of the restoration on improving speech. MATERIALS AND METHODS: Ten patients with an edentulous maxilla were treated with fixed rehabilitation on implants. Speech evaluation was performed at four occasions: before implant surgery, immediately after restoration, and 3 weeks later before and after managing the speech problem by changing the shape of the restoration if speech problems occurred. Comparative three-dimensional-analysis of casts of the restoration before and after changing the shape of the restoration was carried out. RESULTS: The majority of patients (n = 7) experienced speech problems immediately after rehabilitation. Three weeks later, none of the seven patients with deteriorated speech returned to baseline speech. Then, volumetric reduction of the palatal aspects of the (pre)molars was performed, which allowed speech to return to baseline levels in five out of seven patients. In the two remaining patients, the intervention resulted in an improvement of speech without reaching their baseline levels. Three-dimensional-analysis showed that reducing the palatal volume of the premolars was effective in correcting speech. CONCLUSIONS: Speech problems may frequently occur after fixed rehabilitation of the completely edentulous maxilla. A novel speech management concept, consisting of reducing the palatal volume of the (pre)molars, is introduced, demonstrating to solve speech problems in most cases.

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.

Peri-implant bone innervation: histological findings in humans.

PURPOSE: The aim of the present study was to describe nerve fibres around osseointegrated implants in humans. MATERIALS AND METHODS: Twelve mechanically failed implants, retrieved from 10 patients were collected from three dental centres over a period of 5 years. After implant removal, decalcified semi-thin sections (0.5 µm) were stained with thionic methylene blue for light microscopic analysis. In addition, an ultrastructural analysis was performed on serial ultra-thin sections (0.06 µm) using transmission electron microscopy. RESULTS: Both myelinated and unmyelinated nerve fibres could be identified inside the Haversian canals of the osteonal bone near the implant threads. Myelinated fibres were also located at the woven bone around the implant. However, no differentiated nerve endings could be observed around the implants. CONCLUSIONS: This study shows the presence of nerve fibres in human peri-implant bone. Previous studies in animals showed that those fibres participate in the process of bone modelling and remodelling. Yet, the role of peri-implant bone innervation in the osseoperception phenomenon cannot be ruled out since the mechanism of mechanoreception in bone is not fully understood.

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.

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.

Long-term clinical, microbiological, and radiographic outcomes of Brånemark™ implants installed in augmented maxillary bone for fixed full-arch rehabilitation.

PURPOSE: The purpose of this study was to document the long-term outcome of Brånemark implants installed in augmented maxillary bone and to identify parameters that are associated with peri-implant bone level. MATERIAL AND METHODS: Patients of a periodontal practice who had been referred to a maxillofacial surgeon for iliac crest bone grafting in the atrophic maxilla were retrospectively recruited. Five months following grafting, they received 7-8 turned Brånemark implants. Following submerged healing of another 5 months, implants were uncovered and restorative procedures for fixed rehabilitation were initiated 2-3 months thereafter. The primary outcome variable was bone level defined as the distance from the implant-abutment interface to the first visible bone-to-implant contact. Secondary outcome variables included plaque index, bleeding index, probing depth, and levels of 40 species in subgingival plaque samples as identified by means of checkerboard DNA-DNA hybridization. RESULTS: Nine out of 16 patients (eight females, one male; mean age 59) with 71 implants agreed to come in for evaluation after on average 9 years (SD 4; range 3-13) of function. One implant was deemed mobile at the time of inspection. Clinical conditions were acceptable with 11% of the implants showing pockets ≥ 5 mm. Periodontopathogens were encountered frequently and in high numbers. Clinical parameters and bacterial levels were highly patient dependent. The mean bone level was 2.30 mm (SD 1.53; range 0.00-6.95), with 23% of the implants demonstrating advanced resorption (bone level > 3 mm). Regression analysis showed a significant association of the patient (p < .001) and plaque index (p = .007) with bone level. CONCLUSIONS: The long-term outcome of Brånemark implants installed in iliac crest-augmented maxillary bone is acceptable; however, advanced peri-implant bone loss is rather common and indicative of graft resorption. This phenomenon is patient dependent and seems also associated with oral hygiene.

Effective dose range for dental cone beam computed tomography scanners.

OBJECTIVE: To estimate the absorbed organ dose and effective dose for a wide range of cone beam computed tomography scanners, using different exposure protocols and geometries. MATERIALS AND METHODS: Two Alderson Radiation Therapy anthropomorphic phantoms were loaded with LiF detectors (TLD-100 and TLD-100 H) which were evenly distributed throughout the head and neck, covering all radiosensitive organs. Measurements were performed on 14 CBCT devices: 3D Accuitomo 170, Galileos Comfort, i-CAT Next Generation, Iluma Elite, Kodak 9000 3D, Kodak 9500, NewTom VG, NewTom VGi, Pax-Uni3D, Picasso Trio, ProMax 3D, Scanora 3D, SkyView, Veraviewepocs 3D. Effective dose was calculated using the ICRP 103 (2007) tissue weighting factors. RESULTS: Effective dose ranged between 19 and 368 µSv. The largest contributions to the effective dose were from the remainder tissues (37%), salivary glands (24%), and thyroid gland (21%). For all organs, there was a wide range of measured values apparent, due to differences in exposure factors, diameter and height of the primary beam, and positioning of the beam relative to the radiosensitive organs. CONCLUSIONS: The effective dose for different CBCT devices showed a 20-fold range. The results show that a distinction is needed between small-, medium-, and large-field CBCT scanners and protocols, as they are applied to different indication groups, the dose received being strongly related to field size. Furthermore, the dose should always be considered relative to technical and diagnostic image quality, seeing that image quality requirements also differ for patient groups. The results from the current study indicate that the optimisation of dose should be performed by an appropriate selection of exposure parameters and field size, depending on the diagnostic requirements.

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 2-year prospective study on immediate loading with fluoride-modified implants in the edentulous mandible.

OBJECTIVES: Chemically modified surfaces were introduced during the last decade to improve indications for implant treatment. The fluoride-modified implant (Osseospeed(®)) was launched in 2004 and clinical studies suggest a more rapid bone formation and stronger bone to implant contact. However, limited clinical data are available on marginal bone loss and the outcome after >1 year under immediate loading conditions is not fully understood. Hence, the purpose of this prospective study was to present implant survival and marginal bone level data when fluoride-modified implants are supporting a fully functional rehabilitation from the day after surgery in the completely edentulous mandible. MATERIALS AND METHODS: Twenty-five patients, completely edentulous in the mandible, were consecutively treated with five fluoride-modified implants that were functionally loaded with a provisional screw retained restoration. Marginal bone loss was measured from day of surgery to 3, 6, 12 and 24 months. Implants were considered successful after 24 months if radiographic bone loss did not exceed 1 mm and no pain or mobility was caused under a torque of 20 N cm. Statistical analysis was carried out on both patient and implant levels. RESULTS: All implants survived and mean bone loss on implant level after 3, 6, 12 and 24 months was 0.14, 0.13, 0.11 and 0.11 mm, respectively. Bone loss was only statistically significant between baseline and 3 months (P<0.001) and remained unchanged afterward. None of the implants lost >1 mm of bone after 2 years. On the patient level, the mean bone loss after 2 years was 0.12 mm (SD 0.14; range -0.06 to 0.55) with probing pocket depth 2.45 mm (SD 0.43; range 1.3-3.1) and bleeding index 0.55% (SD 0.34; range 0-1). CONCLUSION: Immediate loading of fluoride-modified implants is a predictable treatment yielding a high survival and success rate after 2 years.

The peri-implant sulcus compared with internal implant and suprastructure components: a microbiological analysis.

PURPOSE: A recent in vivo study has shown considerable contamination of internal implant and suprastructure components with great biodiversity, indicating bacterial leakage along the implant-abutment interface, abutment-prosthesis interface, and restorative margins. The goal of the present study was to compare microbiologically the peri-implant sulcus to these internal components on implants with no clinical signs of peri-implantitis and in function for many years. Checkerboard DNA-DNA hybridization was used to identify and quantify 40 species. MATERIAL AND METHODS: Fifty-eight turned titanium Brånemark implants in eight systemically healthy patients (seven women, one man) under regular supportive care were examined. All implants had been placed in the maxilla and loaded with a screw-retained full-arch bridge for an average of 9.6 years. Gingival fluid samples were collected from the deepest sulcus per implant for microbiological analysis. As all fixed restorations were removed, the cotton pellet enclosed in the intra-coronal compartment and the abutment screw were retrieved and microbiologically evaluated. RESULTS: The pellet enclosed in the suprastructure was very similar to the peri-implant sulcus in terms of bacterial detection frequencies and levels for practically all the species included in the panel. Yet, there was virtually no microbial link between these compartments. When comparing the abutment screw to the peri-implant sulcus, the majority of the species were less frequently found, and in lower numbers at the former. However, a relevant link in counts for a lot of bacteria was described between these compartments. Even though all implants in the present study showed no clinical signs of peri-implantitis, the high prevalence of numerous species associated with pathology was striking. CONCLUSIONS: Intra-coronal compartments of screw-retained fixed restorations were heavily contaminated. The restorative margin may have been the principal pathway for bacterial leakage. Contamination of abutment screws most likely occurred from the peri-implant sulcus via the implant-abutment interface and abutment-prosthesis interface.

Effect of implant design on preservation of marginal bone in the mandible.

BACKGROUND: Implant design and surface may have an influence on the marginal bone response during immediate functional loading. AIM: The purpose of this study was to radiographically study the effect of implant design on marginal bone preservation at immediately loaded implants used for prosthetic rehabilitation of the completely edentulous mandible. MATERIALS AND METHODS: A total of 39 patients, previously treated with five implants for support of a full-arch fixed bridge in the mandible, were included in the study. Either machined Brånemark implants (Ma) (Nobel Biocare AB, Gothenburg, Sweden) or surface modified Astra Tech implants with (Mi) or without a microthreaded neck (Ti) (TiOblast, AstraTech AB, Mölndal, Sweden) were used. All fixtures were loaded with a provisional glass fiber or metal-reinforced screw-retained restoration within 24 hours. The provisional restorations were replaced by a 12-unit screw-retained metal-ceramic or metal-resin cantilever bridge after 3 months. Bone loss from baseline to 1 year of loading was measured by means of intraoral radiographs. Only patients with baseline and 1-year radiographs of all implants were selected for comparison. Statistical analysis was carried out on both patient and implant levels. RESULTS: The survival rates after 1 year in function were 98.6, 100, and 100% for the Ma, Ti, and Mi implants, respectively. The overall mean bone loss after 1 year was 1.03 mm (SD 0.87; range -0.77 to 2.5). The mean bone loss was calculated to 1.52 (SD 0.66) for the Ma group, 0.79 (SD 0.79) for the Ti group, and 0.70 (SD 1.01) for the Mi group. There was a significant difference between Ma and Ti (p = .023) and between Ma and Mi (p = .046) groups but not within Ti and Mi implants (p = .70). These conclusions were also valid when the statistical analysis was performed on implant level. CONCLUSIONS: There is no impact of design and surface on implant survival in the completely edentulous mandible. Bone preservation in immediately loaded implants in the mandible is influenced by implant design and significantly better on surface-modified AstraTech implants compared with machined Brånemark implants. In the mandible, a microthread design of the implant collar does not seem to improve bone preservation.

Patient-centered outcome of immediately loaded implants in the rehabilitation of fully edentulous jaws.

INTRODUCTION: Edentulism often involves functional, esthetic, phonetic and psychological problems. OBJECTIVES: To evaluate patient-centered outcomes of full-arch screw-retained rehabilitation on immediately loaded implants. MATERIAL AND METHODS: Fifty patients treated with Astra Tech(TM) implants answered self-administered questionnaires on a visual analogue scale (VAS) 100 mm scale or with multiple-choice or open questions: at baseline, 1 week, 3 or 6 months and 1 year. Changes of VAS in time were analyzed using mixed models for repeated measures, adjusting for gender, age and jaw; comparison of cross-sectional parameters between jaws was performed with the Mann-Whitney U- or chi(2)-test, all at the 0.05 significance level. RESULTS: The median calculated general satisfaction score increased from 40.25 (mean=40.9; SD=23.82; range=0-95) at baseline to 98.25 (mean=95.3; SD=6.68; range=74-100) after 1 year. Overall comfort, eating comfort, speaking comfort and perceived esthetics improved significantly within 1 week after surgery and immediate provisionalization. This did not change significantly until the final bridge was installed after 3 months (mandible) or 6 months (maxilla), when a further significant improvement was demonstrated. The most common postoperative complication was swelling, especially in the maxilla. The importance of one-stage surgery and immediate loading was rated very high by patients before treatment, especially in the mandible. The main reason for choosing fixed prosthetics was eating comfort. Phonetics and esthetics were more important in the maxilla than in the mandible. CONCLUSION: Immediate full-arch rehabilitation yeilds an instant significant improvement in general patient satisfaction and self-perceived factors related to comfort, function and esthetics. Eating comfort is the main concern for the patient and shows the highest improvement. Postoperative complications are limited and patients considered immediate loading important.

Immediate functional loading of TiOblast dental implants in full-arch edentulous maxillae: a 3-year prospective study.

INTRODUCTION: Immediate functional loading of dental implants for full-arch restoration is a patient-friendly approach, shown to be feasible with a good long-term prognosis in a completely edentulous mandible. For the complete restoration of the maxilla, acceptable long-term clinical follow-up is lacking or based on case reports rather than on prospective studies. OBJECTIVES: This prospective mono-centre study reports the 3-year outcome of immediately functionally loaded Astra Tech Dental implants in completely edentulous maxillae based on clinical survival and success based on radiographical assessment of bone level. MATERIAL AND METHODS: One hundred and ninety-five Astra Tech TiOblast surface fixtures were installed in 25 consecutively treated patients (age range: 42-76 years), of whom eight were smokers, 12 had a confirmed history of periodontitis and six had poor bone quality normally deemed for delayed loading. Fixtures and abutments were inserted in a one-stage procedure and functionally loaded within 24 h with a 10-unit provisional glass-fibre or metal-reinforced screw-retained restoration. After 6 months, each implant was checked for stability using a manual torque of 20 N cm and the provisional restoration was replaced by a 10-12-unit screw-retained metal-ceramic or metal-resin cantilever bridge. Bone level was assessed radiographically from the day of surgery up to 3 years and used to calculate mean bone loss at the patient level and individual implant success. RESULTS: No failures occurred in implants or prostheses, the total survival rate being 100%. Mean marginal bone loss was 0.58 mm (SD 0.58); 0.6 mm (SD 0.53); 0.63 (SD 0.61); and 0.72 (SD 0.63) after 6 and 12 months, and 2 and 3 years, respectively, yielding a 100% success at the patient level. Wilcoxon's signed ranks test showed only statistically significant bone loss between baseline and 6 months and a steady-state condition during all other intervals. At the individual fixture level, 82% lost <1 mm marginal bone between baseline and 1 year. After 3 years, 86% have <1.5 mm total bone loss and can be considered a success. The fixtures expressing more bone loss were all inserted in smokers. CONCLUSION: Immediate loading of a full-arch maxillary bridgework on 7-9 Astra Tech TiOblast implants is a predictable treatment option with 100% fixture survival and stable bone-to-implant contact up to 3 years. The steady state in bone remodelling is indicative of a good long-term prognosis in non-smokers but smokers seem to be more prone to bone loss.

Correlation between early perforation of cover screws and marginal bone loss: a retrospective study.

AIM: This retrospective study aimed to determine the consequence of early cover screw exposure on peri-implant marginal bone level. MATERIAL AND METHODS: Sixty Astra Tech MicroThread implants installed in partially edentulous jaws were compared: 20 implants were placed following a two-stage procedure and were unintentionally exposed to the oral cavity (two-stage exposed), 20 implants were placed following a two-stage procedure and were surgically exposed after a subgingival healing time of 3-6 months (two-stage submerged), and 20 implants were placed following a one-stage surgical protocol (one-stage). Digital radiographs were taken at implant placement for all implants, and after abutment surgery for the two-stage exposed and two-stage submerged groups or after 3 months for the one-stage group. Bone loss mesially and distally was measured with an on-screen cursor after calibration. RESULTS: Mean bone re-modelling was 1.96 mm (range: 0.2-3.2 mm) around the two-stage exposed implants, 0.01 mm (range: 0.0-0.3 mm) around the two-stage submerged implants and 0.14 mm (range: 0.0-1.2 mm) around the one-stage implants. CONCLUSION: The unintentional perforation of two-stage implants resulted in significant bone destruction, probably because the biological width was not considered.

Immediate loading in the completely edentulous mandible: technical procedure and clinical results up to 3 years of functional loading.

OBJECTIVES: This prospective mono-center study describes a clinical technique to provide dental implants with a temporary cross-arch cantilever bridge functionally loaded on the day of fixture insertion and discusses the 3-year follow-up of four to six machined surface Brånemark implants installed in the interforamina area. MATERIAL AND METHODS: Ninety Brånemark implants were installed in 18 edentulous mandibles. Five patients were heavy smokers and one had Down syndrome. The day of surgery, a 10 unit provisional glassfiber-reinforced cantilever bridge was installed. The final 12 unit bridge was in place after an average of 144 days (range 10-332). Bone-to-implant level was assessed radiologically from the day of surgery up to 3 years. RESULTS: Two out of five fixtures were lost within 3 months in the Down syndrome patient but the provisional bridge continued to function on the three remaining implants until the patient was successfully reoperated. Another implant was lost after 11 months due to a non-detected fracture in the metal framework, resulting in overloading of the cantilever part. As no additional losses occurred during the follow-up time (range 57-26 months), the total failure rate is 3/91 (3.3%). Seventeen of the 18 patients are loading their implants more than 3 years and nine have moved beyond the 4-year period. Average bone remodelling as measured on the apical radiographs from 12 patients at 0, 12 and 36 months revealed a statistically significant bone loss from the initial 0.1 mm [standard deviation (SD) 0.2; range 0-0.7] toward 1.8 mm (SD 0.2; range 1.6-2.2) during the first year of function. (Wilcoxon's signed rank test; P<0.002). After 3 years, no further significant bone loss occurred. CONCLUSION: This 3-year study shows that machined surface Brånemark implants can be immediately loaded with cross-arch cantilever bridges with an average bone-remodelling pattern indicative of a steady state after 1 year of loading.