Adjunctive local antibiotic therapy in the treatment of peri-implantitis II: clinical and radiographic outcomes

AIM: To monitor over 12 months clinical and radiographic changes occurring after adjunctive local delivery of minocycline microspheres for the treatment of peri-implantitis. MATERIAL AND METHODS: In 25 partially edentulous subjects, 31 implants diagnosed with peri-implantitis were treated. Three weeks after oral hygiene instruction, mechanical debridement and local antiseptic cleansing using 0.2% chlorhexidine gel, baseline (Day 0) parameters were recorded. Minocycline microspheres (Arestin) were locally delivered to each implant site with bone loss and a probing pocket depth (PPD) >or=5 mm. Rescue therapy with Arestin was allowed at Days 180 and 270 at any site exhibiting an increase in PPD>or=2 mm from the previous visit. The following clinical parameters were recorded at four sites/implant at Day 0, 10, 30, 60, 90, 180, 270 and 360: PPD, clinical attachment level (CAL), bleeding on probing (BOP) and plaque index (PlI). RESULTS: Six implants in six subjects were either rescued or exited because of persisting active peri-implantitis. Successful implants showed a statistically significant reduction in both PPD and percentage of sites with BOP between baseline and Day 360 (P<0.05). At mesial implant sites, the mean PPD reduction amounted to 1.6 mm (95% CI: 0.9-2.2 mm, P<0.001) and was accompanied by a statistically significant reduction of the BOP value (P<0.001). Binary regression analysis showed that the clinical parameters and smoking history could not discriminate between successfully treated and rescued or exited implants at any observation time point. CONCLUSION: Non-surgical mechanical treatment of peri-implantitis lesions with adjunctive local delivery of microencapsulated minocycline led to positive effects on clinical parameters up to 12 months.

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.

Clinical and radiographic outcomes at 2 years and the effect of tocilizumab discontinuation following sustained remission in the second and third year of the ACT-RAY study

OBJECTIVE To assess the efficacy and safety of tocilizumab (TCZ) plus methotrexate/placebo (MTX/PBO) over 2 years and the course of disease activity in patients who discontinued TCZ due to sustained remission. METHODS ACT-RAY was a double-blind 3-year trial. Patients with active rheumatoid arthritis despite MTX were randomised to add TCZ to ongoing MTX (add-on strategy) or switch to TCZ plus PBO (switch strategy). Using a treat-to-target approach, open-label conventional synthetic disease-modifying antirheumatic drugs (csDMARDs), other than MTX, were added from week 24 if Disease Activity Score in 28 joints based on erythrocyte sedimentation rate (DAS28-ESR) >3.2. Between weeks 52 and 104, patients in sustained clinical remission (DAS28-ESR <2.6 at two consecutive visits 12 weeks apart) discontinued TCZ and were assessed every 4 weeks for 1 year. If sustained remission was maintained, added csDMARDs, then MTX/PBO, were discontinued. RESULTS Of the 556 randomised patients, 76% completed year 2. Of patients entering year 2, 50.4% discontinued TCZ after achieving sustained remission and 5.9% achieved drug-free remission. Most patients who discontinued TCZ (84.0%) had a subsequent flare, but responded well to TCZ reintroduction. Despite many patients temporarily stopping TCZ, radiographic progression was minimal, with differences favouring add-on treatment. Rates of serious adverse events and serious infections per 100 patient-years were 12.2 and 4.4 in add-on and 15.0 and 3.7 in switch patients. In patients with normal baseline values, alanine aminotransferase elevations >3×upper limit of normal were more frequent in add-on (14.3%) versus switch patients (5.4%). CONCLUSIONS Treat-to-target strategies could be successfully implemented with TCZ to achieve sustained remission, after which TCZ was stopped. Biologic-free remission was maintained for about 3 months, but most patients eventually flared. TCZ restart led to rapid improvement. TRIAL REGISTRATION NUMBER NCT00810199.

Implants placed in fresh extraction sockets in the maxilla: clinical and radiographic outcomes from a 3-year follow-up examination

AIM The aim of this prospective, randomized, controlled multicenter study was to determine the 3-year efficacy and stability of the soft and hard tissues at implants with a different geometry that were placed in fresh extraction sockets. MATERIAL AND METHODS Implants with two different configurations, cylindrical (Group A) or conical/cylindrical (Group B) were installed, and healing abutments were attached. Sixteen weeks after implant placement, subjects returned for a re-entry procedure. Prosthetic restorations were delivered 22 weeks after implant placement. Each subject was placed in a 3-year follow-up program, including examinations at yearly visits including various soft tissue and bone level parameters. RESULTS The percentage of sites that were considered inflamed during the follow-up period was stable and varied between 8.8% and 10.2%. The radiographic examinations documented improved bone levels at the final examination and the mean improvement from baseline (placement of permanent restoration; PR) amounted to 0.17 ± 0.67 mm. More than 70% (54 of 76) of the implants monitored in this study suffered no bone loss during the maintenance period. Moreover, there was an obvious "gain" of interproximal soft tissue volume and at the 3-year examination around 25% of all embrasure gaps were completely filled with "papillae". CONCLUSIONS Both conical/cylindrical and cylindrical implants placed in fresh extraction sockets allowed proper soft and hard tissue healing to occur. At both types of implants, mucosal inflammation was infrequent, marginal bone levels were maintained, and soft tissue volume increased gradually after the placement of the permanent restoration.

Clinical and radiographic outcomes of a combined resective and regenerative approach in the treatment of peri-implantitis: a prospective case series

AIM To assess the clinical and radiographic outcomes applying a combined resective and regenerative approach in the treatment of peri-implantitis. MATERIALS AND METHODS Subjects with implants diagnosed with peri-implantitis (i.e., pocket probing depth (PPD) ≥5 mm with concomitant bleeding on probing (BoP) and ≥2 mm of marginal bone loss or exposure of ≥1 implant thread) were treated by means of a combined approach including the application of a deproteinized bovine bone mineral and a collagen membrane in the intrabony and implantoplasty in the suprabony component of the peri-implant lesion, respectively. The soft tissues were apically repositioned allowing for a non-submerged healing. Clinical and radiographic parameters were evaluated at baseline and 12 months after treatment. RESULTS Eleven subjects with 11 implants were treated and completed the 12-month follow-up. No implant was lost yielding a 100% survival rate. At baseline, the mean PPD and mean clinical attachment level (CAL) were 8.1 ± 1.8 mm and 9.7 ± 2.5 mm, respectively. After 1 year, a mean PPD of 4.0 ± 1.3 mm and a mean CAL of 6.7 ± 2.5 mm were assessed. The differences between the baseline and the follow-up examinations were statistically significant (P = 0.001). The mucosal recession increased from 1.7 ± 1.5 at baseline to 3.0 ± 1.8 mm at the 12-month follow-up (P = 0.003). The mean% of sites with BoP+ around the selected implants decreased from 19.7 ± 40.1 at baseline to 6.1 ± 24.0 after 12 months (P = 0.032). The radiographic marginal bone level decreased from 8.0 ± 3.7 mm at baseline to 5.2 ± 2.2 mm at the 12-month follow-up (P = 0.000001). The radiographic fill of the intrabony component of the defect amounted to 93.3 ± 13.0%. CONCLUSION Within the limits of this study, a combined regenerative and resective approach for the treatment of peri-implant defects yielded positive outcomes in terms of PPD reduction and radiographic defect fill after 12 months.

Immediate implant placement with simultaneous guided bone regeneration in the esthetic zone: 10-year clinical and radiographic outcomes.

AIM To associate the dimension of the facial bone wall with clinical, radiological, and patient-centered outcomes at least 10 years after immediate implant placement with simultaneous guided bone regeneration in a retrospective study. MATERIAL AND METHODS Primary endpoint was the distance from the implant shoulder (IS) to the first bone-to-implant contact (IS-BIC10y ). Secondary endpoints included the facial bone thickness (BT10y ) 2, 4, and 6 mm apical to the IS, and the implant position. At baseline, the horizontal defect width (HDWBL ) from the implant surface to the alveolar wall was recorded. At recall, distance from the IS to the mucosal margin (IS-MM10y ), degree of soft tissue coverage of the mesial and distal aspects of the implants (PISm10y , PISd10y ; Papilla Index), pocket probing depth (PPD10y ), and patient-centered outcomes were determined. Width of the keratinized mucosa (KM), Full-Mouth Plaque and Bleeding Score (FMPS, FMBS) were available for both time points. RESULTS Of the 20 patients who underwent immediate implant placement with simultaneous guided bone regeneration and transmucosal healing, nine males and eight females with a median age of 62 years (42 min, 84 max) were followed up for a median period of 10.5 y (min 10.1 max 11.5). The 10-year implant survival rate was 100%. Multivariate regression analysis revealed a correlation of the IS-BIC10y , controlled for age and gender, with four parameters: HDWBL (P = 0.03), KMBL -10 (P = 0.02), BT10 4 mm (P = 0.01), and BT10 6 mm (P = 0.01). CONCLUSION Within the conditions of the present study, the horizontal defect width was the main indicator for the vertical dimension of the facial bone. The facial bone dimension was further associated with a reduction in the width of the keratinized mucosa and the dimension of the buccal bone.

Guided tissue regeneration/deproteinized bovine bone mineral or papilla preservation flaps alone for treatment of intrabony defects. II: radiographic predictors and outcomes

OBJECTIVES: This study reports the secondary analysis of a randomized-controlled clinical trial designed to assess the efficacy of deproteinized bovine mineral and a collagen membrane in the treatment of intrabony defects. The specific aims of this report are (1) to analyse the radiographic bone changes 1 year after therapy and (2) to assess the association between radiographic defect angle and treatment outcomes. MATERIALS AND METHODS: Baseline and 12-month radiographs were collected from 120 patients with advanced chronic periodontitis from 10 centres in seven countries as part of a multi-centre clinical trial. All patients had at least one intrabony defect > or =3 mm in depth. The treatment consisted of simplified or modified papilla preservation flaps to access the defect. After debridement of the area, a deproteinized bovine mineral and a collagen membrane were applied in the test subjects, and omitted in the controls. Main outcome measures were radiographic bone fill and defect resolution 1 year after surgery. RESULTS: One hundred and twenty pairs of radiographs were obtained, of which 110 pairs were measurable (57 tests and 53 controls). One year after treatment, radiographic resolution of the intrabony component was significantly higher in the test group (3.2+/-1.7 mm) when compared with the controls (1.7+/-1.9 mm). Multivariate analysis indicated that the treatment and the baseline radiographic depth of the intrabony defect significantly influenced the radiographic bone fill of the intrabony defect 1 year following treatment. The percentage of resolution of the defect was influenced by the treatment provided and the baseline plaque score. The baseline radiographic defect angle did not show a significant impact on the clinical and radiographic outcomes. CONCLUSIONS: Regenerative periodontal surgery with a deproteinized bovine bone mineral and a collagen membrane offered additional benefits in terms of radiographic resolution of the intrabony defect and predictability of outcomes with respect to papilla preservation flaps alone.

Piezoelectric alveolar ridge-splitting technique with simultaneous implant placement: a cohort study with 2-year radiographic results

PURPOSE Extended grafting procedures in atrophic ridges are invasive and time-consuming and increase cost and patient morbidity. Therefore, ridge-splitting techniques have been suggested to enlarge alveolar crests. The aim of this cohort study was to report techniques and radiographic outcomes of implants placed simultaneously with a piezoelectric alveolar ridge-splitting technique (RST). Peri-implant bone-level changes (ΔIBL) of implants placed with (study group, SG) or without RST (control group, CG) were compared. MATERIALS AND METHODS Two cohorts (seven patients in each) were matched regarding implant type, position, and number; superstructure type; age; and gender and received 17 implants each. Crestal implant bone level (IBL) was measured at surgery (T0), loading (T1), and 1 year (T2) and 2 years after loading (T3). For all implants, ΔIBL values were determined from radiographs. Differences in ΔIBL between SG and CG were analyzed statistically (Mann-Whitney U test). Bone width was assessed intraoperatively, and vertical bone mapping was performed at T0, T1, and T3. RESULTS After a mean observation period of 27.4 months after surgery, the implant survival rate was 100%. Mean ΔIBL was -1.68 ± 0.90 mm for SG and -1.04 ± 0.78 mm for CG (P = .022). Increased ΔIBL in SG versus CG occurred mainly until T2. Between T2 and T3, ΔIBL was limited (-0.11 ± 1.20 mm for SG and -0.05 ± 0.16 mm for CG; P = .546). Median bone width increased intraoperatively by 4.7 mm. CONCLUSIONS Within the limitations of this study, it can be suggested that RST is a well-functioning one-stage alternative to extended grafting procedures if the ridge shows adequate height. ΔIBL values indicated that implants with RST may fulfill accepted implant success criteria. However, during healing and the first year of loading, increased IBL alterations must be anticipated.

Immediate transmucosal implant placement in molar extraction sites: a 12-month prospective multicenter cohort study

AIM: To assess the clinical and radiographic outcomes of immediate transmucosal placement of implants into molar extraction sockets. STUDY DESIGN: Twelve-month multicenter prospective cohort study. MATERIAL AND METHODS: Following molar extraction, tapered implants with an endosseous diameter of 4.8 mm and a shoulder diameter of 6.5 mm were immediately placed into the sockets. Molars with evidence of acute periapical pathology were excluded. After implant placement and achievement of primary stability, flaps were repositioned and sutured allowing a non-submerged, transmucosal healing. Peri-implant marginal defects were treated according to the principles of guided bone regeneration (GBR) by means of deproteinized bovine bone mineral particles in conjunction with a bioresrobable collagen membrane. Standardized radiographs were obtained at baseline and 12 months thereafter. Changes in depth and width of the distance from the implant shoulder (IS) and from the alveolar crest (AC) to the bottom of the defect (BD) were assessed. RESULTS: Eighty-two patients (42 males and 40 females) were enrolled and followed for 12 months. They contributed with 82 tapered implants. Extraction sites displayed sufficient residual bone volume to allow primary stability of all implants. Sixty-four percent of the implants were placed in the areas of 36 and 46. GBR was used in conjunction with the placement of all implants. No post-surgical complications were observed. All implants healed uneventfully yielding a survival rate of 100% and healthy soft tissue conditions after 12 months. Radiographically, statistically significant changes (P<0.0001) in mesial and distal crestal bone levels were observed from baseline to the 12-month follow-up. CONCLUSIONS: The findings of this 12-month prospective cohort study showed that immediate transmucosal implant placement represented a predictable treatment option for the replacement of mandibular and maxillary molars lost due to reasons other than periodontitis including vertical root fractures, endodontic failures and caries.

Mean 20-year followup of Bernese periacetabular osteotomy

The goal of the Bernese periacetabular osteotomy is to correct the deficient acetabular coverage in hips with developmental dysplasia to prevent secondary osteoarthrosis. We determined the 20-year survivorship of symptomatic patients treated with this procedure, determined the clinical and radiographic outcomes of the surviving hips, and identified factors predicting poor outcome. We retrospectively evaluated the first 63 patients (75 hips) who underwent periacetabular osteotomy at the institution where this technique was developed. The mean age of the patients at surgery was 29 years (range, 13-56 years), and preoperatively 24% presented with advanced grades of osteoarthritis. Four patients (five hips) were lost to followup and one patient (two hips) died. The remaining 58 patients (68 hips) were followed for a minimum of 19 years (mean, 20.4 years; range, 19-23 years) and 41 hips (60%) were preserved at last followup. The overall mean Merle d'Aubigné and Postel score decreased in comparison to the 10-year value and was similar to the preoperative score. We observed no major changes in any of the radiographic parameters during the 20-year postoperative period except the osteoarthritis score. We identified six factors predicting poor outcome: age at surgery, preoperative Merle d'Aubigné and Postel score, positive anterior impingement test, limp, osteoarthrosis grade, and the postoperative extrusion index. Periacetabular osteotomy is an effective technique for treating symptomatic developmental dysplasia of the hip and can maintain the natural hip at least 19 years in selected patients. LEVEL OF EVIDENCE: Level III, prognostic study.

Ten-year results of a three-arm prospective cohort study on implants in periodontally compromised patients. Part 1: implant loss and radiographic bone loss

OBJECTIVES: The aim of this study was to compare the long-term outcomes of implants placed in patients treated for periodontitis periodontally compromised patients (PCP) and in periodontally healthy patients (PHP) in relation to adhesion to supportive periodontal therapy (SPT). MATERIAL AND METHODS: One hundred and twelve partially edentulous patients were consecutively enrolled in private specialist practice and divided into three groups according to their initial periodontal condition: PHP, moderate PCP and severe PCP. Perio and implant treatment was carried out as needed. Solid screws (S), hollow screws (HS) and hollow cylinders (HC) were installed to support fixed prostheses, after successful completion of initial periodontal therapy (full-mouth plaque score <25% and full-mouth bleeding score <25%). At the end of treatment, patients were asked to follow an individualized SPT program. At 10 years, clinical measures and radiographic bone changes were recorded by two calibrated operators, blinded to the initial patient classification. RESULTS: Eleven patients were lost to follow-up. During the period of observation, 18 implants were removed because of biological complications. The implant survival rate was 96.6%, 92.8% and 90% for all implants and 98%, 94.2% and 90% for S-implants only, respectively, for PHP, moderate PCP and severe PCP. The mean bone loss was 0.75 (+/- 0.88) mm in PHP, 1.14 (+/- 1.11) mm in moderate PCP and 0.98 (+/- 1.22) mm in severe PCP, without any statistically significant difference. The percentage of sites, with bone loss > or =3 mm, was, respectively, 4.7% for PHP, 11.2% for moderate PCP and 15.1% for severe PCP, with a statistically significant difference between PHP and severe PCP (P<0.05). Lack of adhesion to SPT was correlated with a higher incidence of bone loss and implant loss. CONCLUSION: Patients with a history of periodontitis presented a lower survival rate and a statistically significantly higher number of sites with peri-implant bone loss. Furthermore, PCP, who did not completely adhere to the SPT, were found to present a higher implant failure rate. This underlines the value of the SPT in enhancing the long-term outcomes of implant therapy, particularly in subjects affected by periodontitis, in order to control reinfection and limit biological complications.

Evolution of radiographic joint damage in rituximab-treated versus TNF-treated rheumatoid arthritis cases with inadequate response to TNF antagonists

Observational studies have suggested that patients with rheumatoid arthritis (RA) who experience inadequate response to anti-tumour necrosis factor (anti-TNF) agents respond more favourably to rituximab (RTX) than to an alternative anti-TNF agent. However, the relative effectiveness of these agents on long-term outcomes, particularly in radiographic damage, remains unclear.

[Impact of tobacco use on the periodontium--an update. Part 2: Clinical and radiographic changes in the periodontium and effects on periodontal and implant therapy]

This third part of a series of publications from the Swiss task force "Smoking--Intervention in the private dental office" on the topic "tobacco use and dental medicine" describes the clinical and radiographic changes of the periodontium within smokers as well as the consequences of tobacco use on periodontal and implant therapy. With increased use of tobacco, patients show higher periodontal probing depths, increased clinical attachment loss, more alveolar bone resorption, a higher prevalence of gingival recessions, and a higher risk for tooth loss. In contrast to this, with smokers, the clinical characteristics of gingival inflammation or bleeding on periodontal probing are less established. Smokers show less positive results after conventional, surgical and regenerative periodontal therapy. The benefits of mucogingval surgery are reduced and less successful in smokers. Moreover, smoking impairs the osseointegration of oral implants and is at least partly responsible for a majority of biological complications in implant dentistry, such as periimplantitis. Based on the present understanding of periodontal diseases, the clinical findings, and the specific therapeutic outcomes with smokers, it appears to be reasonable, next to the current classification of periodontal diseases, to use the term "smokers periodontitis".

Two-year outcome with Nobel Direct implants: a retrospective radiographic and microbiologic study in 10 patients

INTRODUCTION: The Nobel Direct implant (Nobel Biocare AB, Göteborg, Sweden) was developed to minimize marginal bone resorption and to result in "soft tissue integration" for an optimized aesthetic outcome. However, conflicting results have been presented in the literature. The aim of this present study was to evaluate the clinical and microbiologic outcomes of Nobel Direct implants. MATERIALS AND METHODS: Ten partially edentulous subjects without evidence of active periodontitis (mean age 55 years) received 12 Nobel Direct implants. Implants were loaded with single crowns after a healing period of 3 to 6 months. Treatment outcomes were assessed at month 24. Routine clinical assessments, intraoral radiographs, and microbiologic samplings were made. Histologic analysis of one failing implant and chemical spectroscopy around three unused implants was performed. Paired Wilcoxon signed-rank test was used for the evaluation of bone loss; otherwise, descriptive analysis was performed. RESULTS: Implants were functionally loaded after 3 to 6 months. At 2 years, the mean bone loss of remaining implants was 2.0 mm (SD +/- 1.1 mm; range: 0.0-3.4 mm). Three out of 12 implants with an early mean bone loss >3 mm were lost. The surviving implants showed increasing bone loss between 6 and 24 months (p = .028). Only 3 out of the 12 implants were considered successful and showed bone loss of <1.7 mm after 2 years. High rates of pathogens, including Aggregatibacter actinomycetemcomitans, Fusobacterium spp., Porphyromonas gingivalis, Pseudomonas aeruginosa, and Tanerella forsythia, were found. Chemical spectroscopy revealed, despite the normal signals from Ti, O, and C, also peaks of P, F, S, N, and Ca. A normal histologic image of osseointegration was observed in the apical part of the retrieved implant. CONCLUSION: Radiographic evidence and 25% implant failures are indications of a low success rate. High counts and prevalence of significant pathogens were found at surviving implants. Although extensive bone loss had occurred in the coronal part, the apical portion of the implant showed some bone to implant integration.

Long-term outcomes of dental implants with a titanium plasma-sprayed surface: a 20-year prospective case series study in partially edentulous patients

BACKGROUND Long-term studies of ≥10 years are important milestones to get a better understanding of potential factors causing implant failures or complications. PURPOSE The present study investigated the long-term outcomes of titanium dental implants with a rough, microporous surface (titanium plasma sprayed [TPS]) and the associated biologic and technical complications in partially edentulous patients with fixed dental prostheses over a 20-year follow-up period. MATERIALS AND METHODS Sixty-seven patients, who received 95 implants in the 1980s, were examined with well-established clinical and radiographic parameters. Based on these findings, each implant was classified as either successful, surviving, or failed. RESULTS Ten implants in nine patients were lost during the observation period, resulting in an implant survival rate of 89.5%. Radiographically, 92% of the implants exhibited crestal bone loss below 1 mm between the 1- and 20-year follow-up examinations. Only 8% yielded peri-implant bone loss of >1 mm and none exhibited severe bone loss of more than 1.8 mm. During the observation period, 19 implants (20%) experienced a biologic complication with suppuration. Of these 19 implants, 13 implants (13.7%) had been treated and were successfully maintained over the 20-year follow-up period. Therefore, the 20-year implant success rate was 75.8 or 89.5% depending on the different success criteria. Technical complications were observed in 32%. CONCLUSION The present study is the first to report satisfactory success rates after 20 years of function of dental implants with a TPS surface in partially edentulous patients.