Immediate loading of one (fixed-on-1) versus two (fixed-on-2) implants placed flapless supporting mandibular screw-retained cross-arch fixed prostheses: 10-month results from an explanatory randomised controlled trial.

PURPOSE: To evaluate the outcome of one (fixed-on-1, Fo1) versus two (fixed-on-2, Fo2) implants placed flapless in fully edentulous mandibles and immediately restored with metal-resin screw-retained cross-arch prostheses. MATERIALS AND METHODS: Twenty patients with edentulous or to be rendered edentulous mandibles were randomised to the Fo1 group (10 patients who received three intraforaminal implants but only the mesial implant was actually loaded) and to the Fo2 group (10 patients who received two intraforaminal implants) according to a parallel-group design. To be immediately loaded implants had to be inserted with a minimum torque of 60 Ncm. Outcome measures were prosthesis and implant failures, complications and patient satisfaction for function and aesthetics evaluated up to 10 months post-loading. RESULTS: Flaps were raised in three patients of the Fo1 group and one of the Fo2 group. Two prostheses in each group were delayed loaded at 2 and 3 months, because implants could not be inserted with a torque superior to 60 Ncm. Patients of the Fo2 group received prostheses with 12 teeth whereas Fo1 patients with 8 or 10 teeth. Ten months after loading no drop-out or implant failure occurred, but one Fo2 prosthesis had to be remade because the patient complained it was too short (risk difference = 0.1; 95% CI: -0.19 to 0.40; Fisher's exact test P = 1.000). Three patients were affected by complications in each group (risk difference = 0.0; 95% CI: -0.359 to 0.359; Fisher's exact test; P = 1.000). There were no statistically significant differences for prosthetic failures and complications between groups. Four months after loading, patients of the Fo1 group were less satisfied for function than those of the Fo2 group (difference between the medians [Hodges-Lehmann estimation] = 1; 95% CI: 0 to 2; P = 0.043). No differences were observed for aesthetics (difference between the medians [Hodges-Lehmann estimation] = 0; 95% CI: -1 to 0; P = 0.481), and two Fo1 patients would not undergo the same procedure again (difference in proportions: 0.2; 95% CI: -0.11 to 0.51; P = 0.474). CONCLUSIONS: Preliminary results suggest that immediately loaded cross-arch screw-retained fixed prostheses with 8 to 10 teeth can be supported by only one dental implant at least up to 10 months post-loading; however, the clinical application and usefulness of such a procedure remains questionable.

Immediate loading of fixed cross-arch prostheses supported by flapless-placed 5 mm or 11.5 mm long implants: 5-year results from a randomised controlled trial.

PURPOSE: To compare the outcome of cross-arch prostheses supported either by 5 mm long or 11.5 mm long implants placed flapless and immediately restored with a metal-resin screw-retained cross-arch prostheses. MATERIALS AND METHODS: Thirty patients with edentulous or to-be- rendered edentulous mandibles, and 30 with edentulous maxillas, having sufficient bone to allow the placement of four and six implants respectively, of at least 11.5 mm long, were randomised according to a parallel group design into two equal groups and received either 5 mm or 11.5 mm long implants at one centre. Implants had a diameter of 5 mm, were to be placed flapless, and with an insertion torque of at least 50 Ncm. Mandibles received four implants between the mental foramina. Implants were to be immediately loaded with metal-resin definitive prostheses the same day as implant placement. Patients were followed to 5 years post-loading and the outcome measures were: prosthesis and implant failures, complications, and peri-implant marginal bone level changes. RESULTS: Four patients per group dropped out. Two prostheses were remade, one on short maxillary implants and one on long mandibular implants (difference in proportions = 0; 95% CI: -0.15 to 0.15; P = 1.000). Three patients lost six short implants vs three patients who lost four long implants (difference in proportions = 0; 95% CI: -0.19 to 0.19; P = 1.000). Four short implant patients were affected by complications vs five patients with long implants (difference in proportions = 0.04; 95% CI: -0.17 to 0.25; P = 1.000). There were no statistically significant differences for prostheses failures, implant failures and complications. Patients with mandibular short implants lost on average 0.22 mm of peri-implant bone at 5 years while patients with long mandibular implants lost 0.83 mm. Patients with maxillary short implants lost on average 0.30 mm of peri-implant bone at 5 years and patients with long maxillary implants lost 0.89 mm. Short implants showed less bone loss when compared with long implants and the differences up to 5 years were statistically significant both in maxillae (mean difference = 0.59 mm, 95% CI: 0.33 to 0.86 mm, P < .0001) and in mandibles (mean difference = 0.61 mm, 95% CI: 0.36 to 0.86 mm, P < 0.0001). CONCLUSIONS: Flapless-placed 5 mm long implants achieved similar results as 11.5 mm long implants when supporting immediately loaded cross-arch prostheses both in maxillae and mandibles up to 5 years after loading. These results must be confirmed by other trials, and 10 years post-loading data is necessary before making reliable recommendations.

Immediate loading of three (fixed-on-3) vs four (fixed-on-4) implants supporting cross-arch fixed prostheses: 1-year results from a multicentre randomised controlled trial.

PURPOSE: To evaluate the outcome of three (fixed-on-3 = Fo3) vs four (fixed-on-4 = Fo4) implants immediately restored with metal-resin screw-retained cross-arch prostheses in fully edentulous jaws. MATERIALS AND METHODS: Forty-eight edentulous or to be rendered edentulous patients were randomised in six centres (eight patients per centre) to the Fo3 group (24 patients: 12 maxillae and 12 mandibles) and to the Fo4 group (24 patients: 12 maxillae and 12 mandibles) according to a parallel group design. To be immediately loaded, implants had to be inserted with a minimum torque of 40 Ncm. Outcome measures were prosthesis and implant failures, complications and peri-implant marginal bone level changes evaluated up to 1 year post-loading. RESULTS: One maxillary prosthesis per group was delayed loaded because implants could not be placed with a torque of at least 40 Ncm. Ten patients in the Fo3 group and four in the Fo4 group had implants placed flapless. One year after loading no drop out occurred. One patient of the Fo3 group lost three implants vs three patients of the Fo4 group who lost four implants, the difference being no statistically significant (risk difference = -0.08; 95% CI: -0.27 to 0.10; Fisher's exact test P = 0.609). One mandibular Fo3 and one maxillary Fo4 prosthesis failed. Six Fo3 patients were affected by complications vs three Fo4 patients (risk difference = 0.12; 95% CI: -0.10 to 0.34; Fisher's exact test; P = 0.461). Both groups lost marginal bone in a statistically significant way (0.22 ± 0.20 mm for Fo3 patients and 0.40 ± 0.21 mm for Fo4 patients), with Fo3 group showing less marginal peri-implant bone loss than Fo4 group (estimate of the difference = -0.18 (standard error: 0.06) mm; 95% CI: -0.30 to -0.06; P = 0.005). There were no differences in clinical outcomes between the six operators. CONCLUSIONS: These preliminary results suggest that immediately loaded cross-arch prostheses of both jaws can be supported by only three dental implants at least up to 1 year post-loading, though longer follow-ups are definitively needed.

Immediate vs early loading of 6.6 mm flapless-placed single implants: 9 years after-loading report of a split-mouth randomised controlled trial.

PURPOSE: To evaluate the long-term effectiveness of 6.6 mm long flapless-placed single implants loaded immediately or early loaded at 6 weeks. MATERIALS AND METHODS: Thirty patients each received two single Nanotite External Hex Biomet 3i implants, which were then randomly allocated to be either immediately or early loaded, according to a split-mouth design. Implants had to be inserted with a torque superior to 40 Ncm. Provisional crowns were put in slight occlusal contact and replaced by definitive crowns 3 months after loading. Patients were followed for 9 years after loading. Outcome measures were implant failures, biological and biomechanical complications, peri-implant marginal bone level changes and patient preference. RESULTS: A total of 29 implants were immediately loaded, while 31 were early loaded. Nine years after loading, three patients dropped out. One implant failed in each group within 2 months after loading. One patient asked for the immediately loaded crown to be remade for aesthetic reasons and then again to have both metal-ceramic crowns replaced by full ceramic crowns. Another patient had his immediately loaded crown remade after repeated debonding. Six patients from each group experienced complications, the difference being not statistically significant (difference of proportions = 0.00; 95% CI -0.20 to 0.20, P = 1.000). Peri-implant bone loss was 0.60 mm for patients with immediately loaded implants and 0.46 mm for early loaded ones, which was not significantly different (mean difference = 0.14 mm, 95% CI -0.13 to 0.41, P = 0.283). All but one patient had no preference for either procedure after 9 years. CONCLUSIONS: Flapless-placed 6.6 mm long single implants can be immediately loaded and remain successful up to 9 years after loading. Conflict-of-interest statement:

Two or three machined vs roughened surface dental implants loaded immediately supporting total fixed prostheses: 1-year results from a randomised controlled trial.

PURPOSE: To compare implants with machined vs roughened surfaces placed flapless in totally edentulous jaws and immediately restored with metal-resin screw-retained cross-arch prostheses. Mandibles were rehabilitated with two implants (Fixed-on-2 or Fo2) and maxillae with three implants (Fixed-on-3 or Fo3). MATERIALS AND METHODS: Forty edentulous or to be rendered edentulous patients (20 in the mandible and 20 in the maxilla) were randomised to the machined group (20 patients: 10 mandibles and 10 maxillae) and to the roughened group (20 patients: 10 mandibles and 10 maxillae) according to a parallel group design. To be immediately loaded implants had to be inserted with a minimum torque of 60 Ncm. Outcome measures were prosthesis and implant failures, complications and peri-implant marginal bone level changes evaluated up to 1 year post-loading. RESULTS: Flaps were raised in four patients from the machined group. Four prostheses on machined implants and three on roughened implants were delayed for loading because a sufficient insertion torque was not obtained. There were no dropouts 1 year after loading. Two maxillary machined implants were lost in two patients (difference in proportions = 0.10; 95% CI = -0.03 to 0.23; P (Fisher's exact test) = 0.487); one maxillary Fo3 prosthesis on machined implants and one mandibular Fo2 prosthesis on roughened implants had to be remade (difference in proportions = 0; 95% CI = -0.14 to 0.14; P (Fisher's exact test) = 1.000). Five patients with machined implants had six complications vs seven patients who had eight complications at roughened implants (difference in proportions = -0.10; 95% CI = -0.38 to 0.18; P (Fisher's exact test) = 0.731). There were no statistically significant differences for implant failures, prosthetic failures or complications between groups. There were no statistically significant differences for marginal peri-implant bone levels between the two groups (estimate of the difference = -0.06 mm; 95% CI = -0.23 to 0.10; P (ANCOVA) = 0.445), with both groups losing marginal bone in a statistically significant way (0.35 ± 0.23 mm for machined and 0.42 ± 0.27 mm for roughened surface). CONCLUSIONS: These preliminary results suggest that immediately loaded cross-arch prostheses can be supported by only two mandibular or three maxillary dental implants at least up to 1 year post-loading, independently of the type of implant surface used. Longer follow-ups are needed to understand whether one of the two-implant surfaces is preferable.

Immediate loading of two (fixed-on-2) vs four (fixed-on-4) implants placed with a flapless technique supporting mandibular cross-arch fixed prostheses: 3-year results from a pilot randomised controlled trial.

PURPOSE: To evaluate the outcome of two vs four implants placed flapless in fully edentulous mandibles and immediately restored with metal-resin screw-retained cross-arch prostheses. MATERIALS AND METHODS: A total of 60 patients from two different centres were randomised: 30 to the fixed-on-2 group and 30 to the fixed-on-4 group according to a parallel group design. To be immediately loaded implants had to be inserted with a minimum torque of 40 Newton/cm (Ncm). Outcome measures were prosthesis and implant failures, complications, and marginal bone level changes. RESULTS: Flaps were raised in 18 patients. Two implants in two patients did not reach the planned insertion torque and were replaced immediately by larger diameter ones. Three years after loading, two patients dropped out from the fixed-on-2 group and one from the fixed-on-4 group. No implant failure or prosthetic failure occurred. A total of 12 fixed-on-2 patients were affected by one complication each vs 13 fixed-on-4 patients. There were no statistically significant differences for complications between groups (difference in proportion = -0.03; 95% CI -29 to 0.22; P [Fisher's exact test] =1.000). There were no statistically significant differences for marginal peri-implant bone loss between the two groups (mean difference = 0.14; CI 95% -0.17 to 0.45; P [ANCOVA] = 0.356), with both groups losing marginal bone in a statistically significant way (1.70 mm for fixed-on-2 implants and 1.56 mm for fixed-on-4 implants). There were statistically significant differences between the two centres, with more bone being lost for the Bologna centre (2.18 vs 1.13 mm; P (ANCOVA) < 0.001). CONCLUSIONS: Up to 3 years after loading, these preliminary results suggest that immediately loaded mandibular cross-arch fixed prostheses can be supported by only two dental implants. Longer follow-ups (about 10 years) are needed to properly evaluate this therapeutic option. Conflict of interest statement: This study was completely self-financed and no funding from the implant manufacturers has been sought or obtained, not even in the form of free materials.

Immediate, immediate-delayed (6†weeks) and delayed (4†months) post-extractive single implants: 1-year post-loading data from a randomised controlled trial.

PURPOSE: To compare the clinical outcome of single implants placed immediately after tooth extraction with implants placed 6 weeks after tooth extraction (immediate-delayed placement), and with implants placed after 4-month extraction and socket healing (delayed placement). MATERIALS AND METHODS: Two-hundred and ten (210) patients requiring a single implant-supported crown to replace a tooth to be extracted were randomised to receive immediate post-extractive implants (70 patients), immediate-delayed implants at 6 weeks (70 patients), and delayed implants after 4 months of healing (70 patients) according to a parallel group design. When needed, patients of the immediate and immediate-delayed group had the socket grafted with a bone substitute and covered with a resorbable membrane at implant placement. Sockets randomised to delayed implants were grafted in the same manner if poorly preserved or in the aesthetic areas (from second upper to second upper premolars). Implants inserted with at least 25 Ncm torque were left to heal unloaded for 4 months, whereas those inserted with less than 25 Ncm were left to heal unloaded for 6 months. Temporary crowns were delivered and were to be replaced by definitive ones after 4 months. Outcome measures were crown and implant failures, complications, peri-implant marginal bone level changes, aesthetically assessed using the pink esthetic score (PES), and patient satisfaction recorded by blinded assessors. Patients were followed up to 1 year post-loading. RESULTS: One year after loading, three patients dropped out from the immediate group, five from the immediate-delayed group, and six from the delayed group. Four implants (6%) failed in the immediate, four (6.2%) in the immediate-delayed, and one (1.6%) from the delayed group (P (chi-square test) = 0.369). Apart from the crowns (which failed due to implant losses), no other crown had to be remade. Six immediate, six immediate-delayed and four delayed implants were affected by one complication each (P (chi-square test) = 0.792). Mean peri-implant marginal bone loss after 1 year was -0.25 ±â€…0.17 mm (CI 95% -0.29; -0.20) at immediate, -0.29 ±â€…0.14 mm (CI 95% -0.32; -0.25) at immediate-delayed, and -0.31 ±â€…0.16 mm (CI 95% -0.35; -0.27) at delayed placed implants (P (Kruskal-Wallis test) = 0.015). One year after loading, the mean total aesthetic score was 12.52, 12.49 and 11.78 at the immediate, immediate-delayed and delayed groups, respectively (P (Kruskal-Wallis test) <0.001). All patients were fully satisfied both with function and aesthetics, and would undergo the same procedure again, with four exceptions (one from the immediate, one from the immediate-delayed and two from the delayed group), who were only partially satisfied with aesthetics (P = 0.785). CONCLUSIONS: No statistically significant differences for failures, complications and patient satisfaction were observed when placing single implants immediately, 6 weeks or 4 months after tooth extraction; nevertheless, failures were more frequent at immediate and immediate-delayed placed implants. Bone level changes were similar between the different procedures, but aesthetics were better results at immediate and immediate-delayed implants. Conflict-of-interest statement: This trial was partially funded by Nobel Biocare Services (code: 2010-894), the manufacturer of the implants evaluated in this investigation; however, data belonged to the authors and by no means did the manufacturer interfere with the conduct of the trial or the publication of the results.

Immediate, immediate-delayed (6†weeks) and delayed (4†months) post-extractive single implants: 4-month post-loading data from a randomised controlled trial.

PURPOSE: To compare the clinical outcome of single implants placed immediately after tooth extraction with implants placed 6 weeks after tooth extraction (immediate-delayed placement), and with implants placed after 4 months of extraction and socket healing (delayed placement). MATERIALS AND METHODS: Two hundred and ten patients requiring a single implant-supported crown to replace a tooth to be extracted were randomised to receive immediate post-extractive implants (70 patients), immediate-delayed implants at 6 weeks (70 patients), and delayed implants after 4 months of healing (70 patients), according to a parallel group design. When needed, patients of the immediate and immediate-delayed group had the socket grafted with a bone substitute and covered with a resorbable membrane at implant placement. Sockets randomised to delayed implants were grafted in the same manner if poorly preserved or in the aesthetic areas (from second upper to second upper premolars). Implants inserted with at least 25 Ncm torque were left to heal unloaded for 4 months, whereas those inserted with less than 25 Ncm were left to heal unloaded for 6 months. Temporary crowns were delivered and were to be replaced by definitive ones after 4 months. Outcome measures were crown and implant failures, complications, peri-implant marginal bone level changes, aesthetics assessed using the pink esthetic score (PES) and patient satisfaction recorded by blinded assessors. RESULTS: Three patients dropped out from the immediate, five from the immediate-delayed and six from the delayed group up to 4-months post-loading. Four implants (6.0%) failed in the immediate, four (6.2%) in the immediate-delayed and one (1.6%) from the delayed group (P (chi-square test) = 0.369). Apart from the crown failures due to implant losses, no other crown had to be remade. Five immediate, six immediate-delayed and three delayed implants were affected by one complication each (P (chi-square test) = 0.601). Mean peri-implant marginal bone loss after 4 months was -0.17 ±â€…0.11 mm (95% CI: -0.20; -0.15) at immediate, -0.20 ±â€…0.09 mm (95% CI: -0.23; -0.18) at immediate-delayed, and -0.24 ±â€…0.12 mm (95% CI: -0.27; -0.21) at delayed placed implants (P (Kruskal Wallis test) = 0.006). At delivery of definitive crowns, 4 months after loading, the mean total aesthetic score was 12.48, 12.38 and 11.71 in the immediate, immediate-delayed and delayed groups, respectively (P (Kruskal Wallis test) < 0.001). All patients were fully satisfied with both function and aesthetics, and would undergo the same procedure again, with four exceptions (one from the immediate, one from the immediate-delayed and two from the delayed group), who were partially satisfied with the aesthetics (P = 0.785). CONCLUSIONS: No statistically significant differences for failures, complications and patient satisfaction were observed when placing single implants immediately, 6 weeks or four months after tooth extraction; nevertheless failures and complications were more frequent for immediate and immediate-delayed placed implants. Bone level changes were similar between the different procedures, but the aesthetics showed better results for immediate and immediate-delayed implants. Conflict-of-interest statement: This trial was partially funded by Nobel Biocare Services AG (code: 2010-894), the manufacturer of the implants evaluated in this investigation, however data belonged to the authors and by no means did the manufacturer interfere with the conduct of the trial or the publication of the results.

Immediate loading of two (fixed-on-2) versus three (fixed-on-3) implants placed flapless supporting cross-arch fixed prostheses: One-year results from a randomised controlled trial.

PURPOSE: To evaluate the outcome of two (fixed-on-2 = FO2) versus three (fixed-on-3 = FO3) implants placed flapless in fully edentulous jaws and immediately restored with metal-resin screw-retained crossarch prostheses. MATERIALS AND METHODS: Forty edentulous or to be rendered edentulous patients (20 in the maxilla and 20 in the mandible) were randomised to the FO2 group (20 patients: 10 in the maxilla and 10 in the mandible) and to the FO3 group (20 patients: 10 in the maxilla and 10 in the mandible) according to a parallel group design. To be immediately loaded, implants had to be inserted with a minimum torque of 60 Ncm. Outcome measures were prosthesis and implant failures, complications and periimplant marginal bone level changes evaluated up to 1-year post-loading. RESULTS: Flaps were raised in four patients and two prostheses were loaded early at 8 weeks in the FO2 group. One year after loading no dropout or implant failure occurred, however one FO2 maxillary prosthesis had to be remade because of repeated screw-loosening (risk difference = 0.05; 95% CI: -0.05 to 0.15; Fisher's exact test P = 1.000). Three FO2 patients were affected by complications versus five FO3 patients (risk difference = -0.1; 95% CI: -0.35 to 0.15; Fisher's exact test; P = 0.695). There were no statistically significant differences for prosthetic failures and complications between groups. There were no statistically significant differences for marginal peri-implant bone levels between the two groups (estimate of the difference = 0.031 mm; 95% Cl: -0.22 to 0.28; P (ancova) = 0.803), with both groups losing marginal bone in a statistically significant way (0.27 mm for FO2 patients and 0.24 mm for FO3 patients). CONCLUSIONS: These preliminary results suggest that immediately loaded cross-arch prostheses can be supported by only two or three dental implants at least up to 1-year post-loading. Longer follow-ups are needed to properly evaluate both these therapeutic options.

Immediate loading of two flapless placed mandibular implants supporting cross-arch fixed prostheses: A 5-year follow-up prospective single cohort study.

PURPOSE: To evaluate the clinical outcome of two implants placed flapless in fully edentulous mandibles and immediately restored with metal-resin screw-retained cross-arch prostheses 5 years after loading. MATERIALS AND METHODS: Eighty consecutive patients were recruited. To be immediately loaded, implants had to be inserted with a minimum torque of 80 Ncm. Forty-six laser-welded titanium and 34 cast silver-palladium frameworks with resin teeth were initially delivered within 8 and 48 h, respectively. Outcome measures, evaluated by two independent assessors included prosthesis and implant failures, complications, marginal bone level changes, implant stability quotient (ISQ) values and patient satisfaction. RESULTS: Five years after loading one patient did not return to the control and 10 prostheses were remade. Two implants failed early in two patients, but they were successfully replaced. Thirty-six complications occurred in 28 patients but were all successfully treated. After 5 years, mean marginal bone loss was 0.69 mm, mean ISQ values decreased from 75.4 to 73.8, and all patients were fully satisfied with the therapy. A post-hoc comparison between the outcome of laser-welded and cast frameworks showed that laser-welded frameworks were affected by significantly more complications (19 patients out of 46 and 6 patients out of 34, respectively; difference in proportion = 0.23, 95% CI: 0.03 to 0.43; Pearson's chi-square test, P = 0.032), therefore such a framework construction should be considered as a long-term temporary prosthesis and not a definitive prosthesis. CONCLUSIONS: Immediately loaded mandibular cross-arch prostheses can be supported by only two implants up to 5 years, if made with a robust cast framework. Longer follow-ups (around 10 years) are still needed to know the prognosis of this treatment modality.

Machined versus roughened immediately loaded and finally restored single implants inserted flapless: Preliminary 6-month data from a split- mouth randomised controlled trial.

PURPOSE: To compare the outcome of immediately loaded single implants with a machined or a roughened surface. MATERIALS AND METHODS: Fifty patients had two implant sites randomly allocated to receive flaplessplaced single Syra implants (Sweden & Martina), one with a machined and one with a roughened surface (sand-blasted with zirconia powder and acid etched), according to a split-mouth design. To be loaded immediately, implants had to be inserted with a torque superior to 50 Ncm. Implants were restored with definitive crowns in direct occlusal contact within 48 h. Patients were followed for 6 months after loading. Outcome measures were prosthetic and implant failures and complications. RESULTS: Two machined implants and four roughened implants were not loaded immediately. Six months after loading no dropout occurred. One implant loaded late, which had a rough implant surface, failed 20 days after loading (P (McNemar test) = 0.625; difference in proportions = -0.04; 95% CI: -0.15 to 0.07). Three crowns had to be remade on machined implants and four on roughened implants (P (McNemar test) = 1.000; difference in proportions = -0.02; 95% CI: -0.12 to 0.08). Three machined and five roughened implants experienced complications (P (McNemar test) = 0.625; difference in proportions = -0.04; 95% CI: -0.15 to 0.07). There were no statistically significant differences between groups for crown and implant losses as well as complications. CONCLUSIONS: Up to 6 months after loading both machined and roughened flapless-placed and immediately loaded single implants provided good and similar results, however, longer follow-ups are needed to evaluate the long-term prognosis of implants with different surfaces.

Immediate loading of bimaxillary total fixed prostheses supported by five flapless-placed implants with machined surfaces: A 6-month follow-up prospective single cohort study.

PURPOSE: To evaluate the clinical outcome of fully edentulous patients rehabilitated with immediately loaded bimaxillary screw-retained metal-resin prostheses supported by five implants placed flapless: two in the mandible and three in the maxillae. MATERIALS AND METHODS: Twenty-five consecutively treated patients were recruited. To be immediately loaded, implants had to be inserted with a minimum torque of 80 Ncm. Outcome measures were prosthesis and implant failures, and complications. RESULTS: Six months after loading no patients dropped out and no prosthesis or implant failed. Two maxillary prostheses were loaded early at 8 weeks because implants were inserted with a torque inferior to 45 Ncm. Three complications occurred in two patients but they were all successfully treated. CONCLUSIONS: Six months after loading, immediately loaded bimaxillary cross-arch prostheses can be supported by only two mandibular and three maxillary flapless-placed dental implants. Longer follow-ups of approximately 10 years are needed to understand the prognosis of this treatment modality.

Immediate loading of fixed cross-arch prostheses supported by flapless-placed supershort or long implants: 1-year results from a randomised controlled trial.

PURPOSE: To compare the outcome of cross-arch prostheses supported either by supershort (5 mm) or long (11.5 mm) implants, placed flapless and immediately restored with metal-resin screw-retained cross-arch prostheses. MATERIALS AND METHODS: Thirty patients with edentulous (or to be rendered edentulous) mandibles and 30 with edentulous maxillas, who had sufficient bone to allow the placement of four and six implants respectively, which were at least 11.5 mm-long, were randomised according to a parallel group design into 2 equal groups, where they received either 5 mm or 11.5 mm-long implants at one centre. Implants with a diameter of 5 mm, were to be placed flapless with an insertion torque of at least 50 Ncm. Mandibles received four implants between the mental foramina. Implants were to be immediately loaded with metal-resin-definitive prostheses on the same day of implant placement. Patients were followed up to 1 year after loading and the outcome measures were: prosthesis and implant failures, complications, and peri-implant marginal bone level changes. RESULTS: No patients dropped-out. Two prostheses were remade, one on short maxillary implants and one on long mandibular implants. Two 5 mm maxillary implants which did not achieve 50 Ncm torque in soft bone of one patient, but were immediately loaded anyway, failed after 3 weeks compared to one mandibular 11.5 mm-long implant that failed after 60 days. Two complications occurred in each group. There were no statistically significant differences for prosthesis failures, implant failures and complications. Patients with mandibular short implants lost on average 0.08 mm of peri-implant bone at 1 year and patients with long mandibular implants lost 0.51 mm. Patients with short maxillary implants lost on average 0.15 mm of peri-implant bone at 1 year and patients with long maxillary implants lost 0.62 mm. Short implants showed less bone loss when compared to long implants and the differences up to 1 year were statistically significant both in maxillae (mean difference = 0.48 mm, 95% CI 0.22 to 0.73, P = 0.0011) and in mandibles (mean difference = 0.44 mm, 95% CI 0.21 to 0.66, P = 0.0009). CONCLUSIONS: Flapless-placed 5 mm-long implants achieved similar results as 11.5 mm-long implants when supporting immediately loaded cross-arch prostheses both in maxillae and mandibles up to 1 year after loading. These preliminary results must be confirmed by other trials, and 5- to 10-year post-loading data is necessary before making reliable recommendations.

Short implants versus longer implants in vertically augmented posterior mandibles: a randomised controlled trial with 5-year after loading follow-up.

OBJECTIVES: To evaluate whether 6.6-mm long implants could be a suitable alternative to longer implants placed in vertically augmented atrophic posterior mandibles. MATERIALS AND METHODS: Sixty partially edentulous patients having 7 to 8 mm of residual crestal height and at least 5.5 mm thickness measured on CT scans above the mandibular canal were randomised according to a parallel group design. They were either to receive 1 to 3 submerged 6.6-mm long implants or 9.6 mm or longer implants (30 patients per group) placed in vertically augmented bone. Bone was augmented with interpositional anorganic bovine bone blocks covered by resorbable barriers. Grafts were left to heal for 5 months before implant placement. Four months after provisional acrylic prostheses were delivered, they were replaced, after 4 months, by definitive metal-ceramic prostheses. Outcome measures were: prosthesis and implant failures; complications; and radiographic peri-implant marginal bone level changes. All patients were followed up to 5 years after loading. RESULTS: Five years after loading, 8 patients dropped out: 3 from the short implant group and 5 from the augmented group. The augmentation procedure failed in 2 patients and only 6.6-mm long implants could be inserted. There were no statistically significant differences for prosthesis and implant failures. Five prostheses failed in 4 patients of the short implant group versus 5 prostheses in 5 patients in the augmented group (Fishers exact test P = 1.0; difference in proportions = 0.07; 95% CI -0.29 to 0.43). Five short implants failed in 3 patients versus 3 long implants in 3 patients (Fishers exact test P = 1.00 difference in proportions = 0.00; 95% CI -0.43 to 0.43). There were statistically more complications in augmented patients (25 complications in 21 augmented patients versus 6 complications in 6 patients of the short implant group) (Fishers exact test P < 0.0001; difference in proportions = 0.60; 95% CI 0.38, 0.82). Both groups gradually lost peri-implant bone in a statistically significant way. Five years after loading, short implant group patients lost an average of 1.49 mm peri-implant bone compared with 2.34 mm in the augmented group. Short implants experienced statistically significantly less bone loss (0.82 mm, 95% CI 0.48; 1.16, P < 0.0001) than long implants. CONCLUSIONS: When residual bone height over the mandibular canal is between 7 to 8 mm, 6.6 mm short implants could be an interesting alternative to vertical augmentation in posterior atrophic mandibles since the treatment is faster, cheaper and associated with less morbidity. Longer follow-ups may still be needed to confirm these results, however the medium-term prognosis (5 years after loading) of short implants is at least as good as those of longer implants placed vertically in augmented mandibles.

Cosci versus Summers technique for crestal sinus lift: 3-year results from a randomised controlled trial.

PURPOSE: To compare the effectiveness of two different techniques to lift the maxillary sinus via a crestal approach: the Summers versus the Cosci technique. MATERIALS AND METHODS: Fifteen partially edentulous patients missing bilaterally maxillary molars and/ or premolars, having 4 to 7 mm of residual crestal height and at least 5 mm thickness below the maxillary sinuses measured on CT scans, were randomised to have implants placed in sinuses crestally lifted according to the Cosci or the Summers techniques, with bone substitutes according to a split-mouth design. Implants were left to heal submerged for 6 months. Implants were loaded with acrylic provisional crowns/prostheses. Screw-retained definitive metal-ceramic prostheses were delivered 4 months after provisional loading. Outcome measures were: prosthesis and implant failures; any complications; operation time; operator preference; patient preference and peri-implant marginal bone level changes assessed by a blinded outcome assessor. All patients were followed to 3 years after implant loading. RESULTS: Nineteen study implants were placed according to each technique. Three years after loading, 3 patients dropped out and no implant failed. No discomfort/complications occurred at sites treated with the Cosci technique, whereas 12 patients reported discomfort during the augmentation procedure at the side treated with the Summers technique; this was statistically significant (P = 0.0005). In one of these patients, a perforation of the sinus membrane occurred. Postoperatively, headache was reported by 9 patients and swelling occurred in 3 of these patients at the Summers treated sides. Statistically significant less time (9.7 mins, SD = 4.0, P < 0.001, 95% CI -11.9 to -7.5) was required to place implants according to the Cosci technique (33 versus 24 mins on average). The 2 operators and 14 out of 15 patients preferred the Cosci technique 1 month after surgery (P = 0.001), and 1 year after surgery (13 out of 15 patients, P = 0.007). The ceramic layer of one prosthesis of the Summers' group and one abutment screw of the Cosci's group loosened between 1 to 3 years post-loading. After 3 years, implants inserted according to the Cosci technique lost 1.39 mm of peri-implant bone versus 1.54 mm for the implants placed with the Summers technique. There were no statistically significant differences for marginal bone level changes between the two groups (difference 0.15 mm, 95% CI -0.11 to 0.41, P = 0.24). CONCLUSIONS: Both crestal sinus lift techniques produced successful results over a 3-year follow-up period, but the Cosci technique required less surgical time, determined less intra- and postoperative morbidity and was preferred by patients. Conflict of interest statement: This was an investigator-initiated trial, however the trial was partially supported by Zimmer Dental Italy, Vittorio Veneto (TV), Italy. One of the authors (Dr Cosci), who treated 8 patients in this study, is the inventor of the Cosci technique and his partipation was a prerequisite of the sponsor to support the trial.

Immediate loading of two flapless placed mandibular implants supporting cross-arch fixed prostheses: a 3-year follow-up prospective single cohort study.

PURPOSE: To evaluate the clinical outcome of two implants placed flapless in fully edentulous mandibles and immediately restored with a metal-resin screw-retained cross-arch prostheses 3 years after loading. MATERIALS AND METHODS: Eighty consecutively patients were recruited. Implants for immediate loading had to be inserted with a minimum torque of 80 Ncm. Outcome measures, evaluated by two independent assessors, were: prosthesis and implant failures, complications, marginal bone level changes, implant stability quotient (ISQ) values and patient satisfaction. RESULTS: Three years after loading, all prostheses were in function although one patient did not come back for the 1- and 3-year follow-ups. Two implants failed early in two patients, but were successfully replaced and their prostheses remade. Twelve complications occurred in 10 patients but were all successfully treated. After 3 years, mean marginal bone loss was 0.43 mm, mean ISQ values decreased from 75.4 to 75.3, and all but four patients were fully satisfied with the therapy. Four patients were partially satisfied because, lacking molars, they could not chew as they wished. CONCLUSION: Immediately loaded mandibular cross-arch partial dentures can be supported by only two dental implants up to 3 years. Longer follow-ups (around 10 years) are needed to know the prognosis of this treatment modality.

Immediate loading of 2(all-on-2) versus 4 (all-on-4) implants placed with a flapless technique supporting mandibular cross-arch fixed prostheses: 1-year results from a pilot randomised controlled trial.

PURPOSE: To evaluate the outcome of 2 versus 4 implants placed flapless in fully edentulous mandibles and immediately restored with metal-resin screw-retained cross-arch prostheses. MATERIALS AND METHODS: Sixty patients from two different centres were randomised: 30 to the allon- 2 group and 30 to the all-on-4 group according to a parallel group design. To be immediately loaded, implants had to be inserted with a minimum torque of 40 Ncm. Outcome measures were prosthesis and implant failures, complications, and marginal bone level changes. RESULTS: Flaps were raised in 18 patients. A total of 2 implants in 2 patients did not reach the planned insertion torque and were immediately replaced by larger diameter ones. One year after loading, no drop-out or implant failure occurred. Eight biomechanical complications occurred in the all-on-2 group versus 8 complications in the all-on-4 group. There were no statistically significant differences for complications between groups. There were no statistically significant differences for marginal peri-implant bone levels between the two groups (estimate of the difference = -0.16; 95%CI -0.40 to 0.08; P (ANCOVA) = 0.074), with both groups losing a statistically significant amount of marginal bone (0.74 mm for all-on-2 implants and 0.58 mm for all-on-4 implants). There were statistically significant differences between the two centres, with more bone being lost for the Bologna centre (0.26 mm versus 1.07 mm). CONCLUSIONS: These preliminary results, up to 1 year after loading, suggest that immediately loaded mandibular cross-arch fixed prostheses can be supported by only 2 dental implants. Longer followups (approximately 10 years) are needed to properly evaluate this therapeutic option.

Early implant loading in the atrophic posterior maxilla: 1-stage lateral versus crestal sinus lift and 8 mm hydroxyapatite-coated implants. A 5-year randomised controlled trial.

PURPOSE: To evaluate the efficacy of long implants (10-16 mm) inserted in maxillary sinuses augmented according to a lateral approach versus short (8 mm) implants placed in crestally augmented sinuses, early loaded after 45 days. MATERIALS AND METHODS: Forty partially or fully edentulous patients having 3 to 6 mm of residual crestal height and at least 4 mm in thickness below the maxillary sinuses were randomised according to a parallel group design to receive either one to three 10 to 16 mm-long hydroxyapatite-coated implants (20 patients) after lateral sinus lifting with 50% an organic bovine (Bio-Oss) and 50% autogenous bone, or 8 mm implants (20 patients) after crestal sinus lifting with autogenous bone. Implants were submerged and left healing for 45 days before loading the implants. Within 1 week after abutment connection, implants were loaded with screw-retained full acrylic provisional prostheses. Definitive metal-ceramic prostheses were provisionally cemented 45 days after abutment connection. Outcome measures were prosthesis and implant failures, any complications, and radiographic periimplant marginal bone level changes. In addition, the stability of individual implants was assessed with Osstell and Periotest at abutment connection (baseline), and at 1 and 5 years after loading by blinded outcome assessors. All patients were followed up to 5 years after loading. RESULTS: One patient dropped out (death) from the longer implant group. One implant failed in the short implant group versus 5 implants in 3 patients of the longer implant group. The difference was not statistically significant. Four complications occurred in 4 patients of the short implant group versus 8 complications in 7 patients of the long implant group, the difference being not statistically significantly different. However, the 2 major postoperative complications occurred in the longer implant group: 1 abscess, and 1 sinusitis that led to the complete failure of the treatment in 2 patients (4 implants lost). A total of 0.72 mm of peri-implant marginal bone was lost after 5 years at long implants and 0.41 mm at short implants, the difference between the two groups was statistically significant (P = 0.028). Osstell values increased and Periotest decreased over time and there were no differences between groups at any time points. CONCLUSIONS: In atrophic maxillary sinuses with a residual bone height of 3 to 6 mm, 8 mm short implants placed in a simultaneously crestally lifted sinus might be a preferable choice than a 1-stage lateral sinus lift for placing longer implants since they appear to be associated with less morbidity. If these implants are placed with an insertion torque >35 Ncm and are joined together under the same prosthesis, they can be early loaded at 6 weeks.

Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone. One-year post-loading results from a pilot randomised controlled trial.

PURPOSE: To evaluate whether 6 mm long by 4 mm wide dental implants could be an alternative to implants at least 10 mm long placed in bone augmented with bone substitutes in posterior atrophic jaws. MATERIALS AND METHODS: A total of 20 patients with bilateral atrophic mandibles and 20 patients with bilateral atrophic maxillae, having 5 to 7 mm of bone height above the mandibular canal or below the maxillary sinus, had each side of the jaws randomly allocated according to a split-mouth design. They were allocated to receive one to three 6 mm long and 4 mm wide implants, or implants at least 10 mm long in augmented bone by two different surgeons in different centres. Mandibles were vertically augmented with interpositional equine bone blocks and resorbable barriers, and implants were placed 3 months later. Maxillary sinuses were augmented with particulated porcine bone via a lateral window and implants were placed simultaneously. All implants were submerged and loaded, after 4 months, with provisional prostheses. Four months later, definitive metal-ceramic prostheses were delivered. Outcome measures were prosthesis and implant failures, any complication and radiographic peri-implant marginal bone level changes. RESULTS: One patient treated in the mandible dropped out before the 1-year post-loading follow-up. All maxillary implants and prostheses were successful, whereas 2 mandibular prostheses could not be placed on implants at least 10 mm long due to graft failures; one was associated with the loss of 3 implants because of infection. There were no statistically significant differences in implant and prosthesis failures, though significantly more complications occurred at grafted sites in mandibles (P = 0.0078), but not in maxillae (P = 0.1250). In total, 14 complications occurred in 12 patients at augmented sites versus none at 6 mm-long implants. All failures and complications occurred before loading. Patients with mandibular 6 mm-long implants lost an average of 1.05 mm of peri-implant bone at 1 year and patients with mandibular implants at least 10 mm long lost 1.07 mm. These differences were statistically significant (P < 0.001). Patients with maxillary 6 mm-long implants lost an average of 1.02 mm of peri-implant bone at 1 year and patients with maxillary implants at least 10 mm long lost 1.09 mm. These differences were statistically significant (P < 0.001). There were no statistically significant differences in bone level changes up to 1 year between 6 mm and at least 10 mm-long implants in both jaws (mandibles n = 18, mean difference -0.02 mm, 95% CI -0.16 to 0.12, P = 0.7384; maxillae n = 20, mean difference -0.07 mm, 95% CI -0.18 to 0.05, P = 0.2547). CONCLUSIONS: Short-term data (1 year after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone. Short implants might be a preferable choice to bone augmentation, especially in posterior mandibles since the treatment is faster, cheaper and associated with less morbidity. However, data obtained 5 to 10 years after loading are necessary before making reliable recommendations. CONFLICT OF INTEREST STATEMENT: Tecnoss and Southern Implants partially supported this trial and donated biomaterials, implants and prosthetic components used in this study. However, the data belonged to the authors and by no means did the manufacturers interfere with the conduct of the trial or the publication of its results.

Immediate versus early loading of 6.5 mm-long flapless-placed single implants: a 4-year after loading report of a split-mouth randomised controlled trial.

PURPOSE: To evaluate the medium-term effectiveness of 6.5 mm-long flapless-placed single implants immediately or early loaded at 6 weeks. MATERIALS AND METHODS: Thirty patients received two single NanoTite external hex Biomet 3i implants each, which were then randomly allocated to be immediately or early loaded according to a splitmouth design. Implants had to be inserted with a minimum torque of >40 Ncm. Provisional crowns were put in slight occlusal contact and replaced by definitive crowns 3 months after loading. Patients were followed for 4 years after loading. Outcome measures were implant failures, biological and biomechanical complications, peri-implant marginal bone level changes, and patient preference. RESULTS: Twenty-nine implants were immediately loaded and 31 early loaded. Four years after loading, no drop-outs occurred. One implant failed in each group within 2 months after loading. Seven patients experienced complications at immediately loaded implants and 6 at early loaded implants. There were no statistically significant differences between groups for implant losses, complications, mean marginal bone level changes and patient preference. CONCLUSIONS: Flapless-placed 6.5 mm-long single implants can be immediately loaded and remain successful up to 4 years after loading. Even longer follow-ups are still needed to evaluate the longterm prognosis of short implants.