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PURPOSE: To present a case of a woman referred for the management of displacement of one implant in her right posterior mandible that had occurred three days previously. MATERIALS AND METHODS: After implant placement, the practitioner was no longer able to detect the implant and inserted a second one at the same site without taking a control radiograph. At the end of surgery, when a radiograph was finally taken, the first implant appeared displaced into the mandible body. The patient suffered total paresthesia on the right lower lip and chin. A flap was raised and bone osteotomies were performed on the lateral side of the mandible to create a rectangular cortical bone window that was removed. The implant was stuck by the second implant placed coronally, and only after unscrewing this second implant was it possible to remove the first one. RESULTS: After 18 months, the patient recovered full sensitivity. CONCLUSIONS: In cases of implant displacement, it is always recommended that appropriate radiographs are performed to visualise where the implants could have been displaced in order to avoid more serious consequences.

International audience; Purpose To evaluate whether 4.0 mm short dental implants could be an alternative to augmentation with xenographs in the maxilla and placement of at least 10.0 mm long implants in posterior atrophic jaws. Materials and methods A group of 40 patients with atrophic posterior (premolar and molar areas) mandibles with 5.0 mm to 6.0 mm bone height above the mandibular canal and 40 patients with atrophic maxillas having 4.0 mm to 5.0 mm below the maxillary sinus, were randomised according to a parallel group design to receive between one and three 4.0 mm long implants or one to three implants of at least 10.0 mm long in augmented bone, at two centres. All implants had a diameter of 4.0 mm or 4.5 mm. Mandibles were vertically augmented with inter-positional equine bone blocks and resorbable barriers. Implants were placed 4 months after the inter-positional grafting. Maxillary sinuses were augmented with particulated porcine bone via a lateral window covered with resorbable barriers, and implants were placed simultaneously. Implants were not submerged and were loaded after 4 months with provisional screw-retained reinforced acrylic restorations replaced after another 4 months by definitive screw-retained metal-composite prostheses. Patients were followed up to 1 year post-loading. Outcome measures were prosthesis and implant failures, any complication, and peri-implant marginal bone level changes. Results Three patients dropped out; one from the maxillary augmented group, one from the mandibular augmented group, and one from the maxillary short implant group. In six augmented mandibles (30%) it was not possible to place implants of at least 10.0 mm, so shorter implants were placed instead. In mandibles, one implant from the augmented group failed vs two 4.0 mm implants in two patients from the short implant group. In maxillae, three short implants failed in two patients vs seven long implants in four patients (two long implants and one short implant dropped into the maxillary sinus). Two prostheses on short implants (one mandibular and one maxillary) were placed at a later stage because of implant failures, vs six prostheses (one mandibular and five maxillary) at augmented sites (one mandibular prosthesis not delivered, three maxillary prostheses delivered with delays, one not delivered, and one failed) at augmented sites. In particular, three patients in the augmented group (one mandible and two maxillae) were not wearing a prosthesis. There were no statistically significant differences in implant failures (P (chi-square test) = 0.693; difference in proportion = 0.03; CI 95% -0.11 to 0.17) or prostheses failures (P (chi-square test) = 0.126; difference in proportion = 0.10; CI 95% -0.03 to 0.24). At mandibular sites, nine augmented patients were affected by complications vs two patients treated with short implants (P (chi-square test) = 0.01; difference in proportion = 0.37; CI 95% 0.11 to 0.63), the difference being statistically significant. No significant differences were found for maxillae nine sinus-lifted patients vs four short implant patients were affected by complications (P (chi-square test) = 0.091; difference in proportion = 0.25; CI 95% -0.03 to 0.53). At 1-year post-loading, average peri-implant bone loss was 0.51 mm at 4 mm long mandibular implants, 0.77 mm at 10 mm or longer mandibular implants, 0.63 mm at short maxillary implants and 0.72 mm at long maxillary implants. The difference was statistically significant in mandibles (mean difference -0.26 mm, 95% CI -0.39 to -0.13, P (ANCOVA) < 0.001), but not in maxillae (mean difference -0.09 mm, 95% CI -0.24 to 0.05, P (ANCOVA) = 0.196). Conclusions One year after loading 4.0 mm long implants achieved similar results, if not better, than longer implants in augmented jaws, but were affected by fewer complications. Short implants might be a preferable choice over bone augmentation, especially in mandibles, since the treatment is less invasive, faster, cheaper, and associated with less morbidity. However, 5 to 10 years post-loading data are necessary before making reliable recommendations. © 2002-2018 Quintessence Publishing Group.

PURPOSE: To evaluate whether 4.0 x 4.0 mm dental implants could be an alternative to implants at least 8.5 mm long, which were placed in posterior jaws in the presence of adequate bone volumes. MATERIALS AND METHODS: One hundred and fifty patients with posterior (premolar and molar areas) mandibles having at least 12.5 mm bone height above the mandibular canal or 11.5 mm bone height below the maxillary sinus, were randomised according to a parallel group design, in order to receive one to three 4.0 mm-long implants or one to three implants which were at least 8.5 mm long, at three centres. All implants had a diameter of 4.0 mm. Implants were loaded after 4 months with definitive screw-retained prostheses. Patients were followed up to 4-month post-loading and outcome measures were prosthesis and implant failures, any complications and peri-implant marginal bone level changes. RESULTS: No patients dropped-out before the 4-month evaluation. Three patients experienced the early failures of one 4.0 mm-long implant each, in comparison to two patients who lost one long implant each (difference in proportion = 0.01; 95% CI -0.06 to 0.09; P = 0.50). Consequently, two prostheses in each group could not be delivered as planned (difference in proportion = 0; 95% CI -0.07 to 0.07; P = 0.69), and one patient from each group is still waiting to have their prostheses delivered. Three short implant patients experienced three complications versus two long implant patients (difference in proportion = 0.01; 95% CI -0.06 to 0.09; P = 0.50). There were no statistically significant differences in prosthesis failures, implant failures and complications. Patients with short implants lost on average 0.38 mm of peri-implant bone at 4 months and patients with long mandibular implants lost 0.42 mm. There were no statistically significant differences in bone level changes up to 4 months between short and long implants (mean difference = 0.04 mm; 95% CI: -0.041 to 0.117; P = 0.274). CONCLUSIONS: Four months after loading, 4.0 x 4.0 mm implants achieved similar results as 8.5 x 4.0 mm-long or longer implants in posterior jaws, however 5 to 10 years post-loading data are necessary before reliable recommendations can be made.

PURPOSE: To evaluate clinical safety and effectiveness of a novel calcium-incorporated titanium implant surface (Xpeed, MegaGen Implant Co., Gyeongbuk, South Korea). MATERIALS AND METHODS: Sixty patients were randomised to receive one to six implants in the maxilla with either calcium-incorporated (Xpeed) or control resorbable blasted media (RBM) surfaces, according to a parallel group design at two centres. Implants were submerged and exposed at three different endpoints in equal groups of 20 patients, each at 12, 10 and 8 weeks, respectively. Within 2 weeks, implants were functionally loaded with provisional or definitive prostheses. Outcome measures were prosthesis failures, implant failures, any complications and peri-implant marginal bone level changes. RESULTS: Thirty patients received 45 calcium-incorporated implants and 30 patients received 42 control titanium implants. Three years after loading four patients dropped-out from the Xpeed group and one from the RBM group. No prosthesis or implant failures occurred. There were no statistically significant differences between the groups for complications (P = 0.91; difference in proportions = 0.79 %; 95% CI -0.71 to 2.29) and mean marginal bone level changes (P = 0.88; mean difference = -0.02 mm; 95% CI -0.26 to 0.22). CONCLUSIONS: Both implant surfaces provided good clinical results and no significant difference was found when comparing titanium implants with a nanostructured calcium-incorporated surface versus implants with RBM surfaces.

PURPOSE: To compare the effectiveness of immediate post-extractive single implants with delayed implants, placed in preserved sockets after 4 months of healing. Implants that achieved an insertion torque of at least 35 Ncm were immediately non-occlusally loaded. MATERIALS AND METHODS: Just after tooth extraction, and in the presence of less than 4 mm of vertical loss of the buccal bone in relation to the palatal wall, 106 patients requiring a single immediate post-extractive implant in the maxilla from second to second premolar were randomly allocated to immediate implant placement (immediate group; 54 patients) or to socket preservation using anorganic bovine bone covered by a resorbable collagen barrier (delayed group; 52 patients), according to a parallel group design at three different centres. Bone-to-implant gaps were to be filled with anorganic bovine bone, however this was not carried out in 17 patients (corresponding to 40% of those who should have been grafted). Four months after socket preservation, delayed implants were placed. Implants inserted with an insertion torque of at least 35 Ncm were immediately loaded with non-occluding provisional single crowns, then replaced after 4 months by definitive crowns. Patients were followed up to 1 year after loading. Outcome measures were implant failures, complications, aesthetics assessed using the pink esthetic score (PES), peri-implant marginal bone level changes and patient satisfaction recorded by blinded assessors. RESULTS: Nineteen (35%) implants were not immediately loaded in the immediate group versus 39 (75%) implants in the delayed placement group because an insertion torque superior to 35 Ncm could not be obtained. Six patients dropped out 4 months after loading from the delayed group versus none in the immediate group. Two implants failed in the immediate group (6%) versus none in the delayed group, with the difference showing no statistical significance (difference in proportions = 0.04; 95% CI: -0.03 to 0.11; P = 0.187). Eight minor complications occurred in the immediate group and one in the delayed group, and this was statistically significant (difference in proportions = 0.13; 95% CI: 0.03 to 0.23; P = 0.028). At delivery of definitive crowns, 4 months after loading, the mean aesthetic score was 12.8 and 12.6 in the immediate and delayed groups, respectively. At 1 year after loading, the mean aesthetic score was 13.0 and 12.8 in the immediate and delayed groups, respectively. There was no statistically significant difference at 4 months (P = 0.500) and at 1 year (P = 0.615). Marginal bone levels at implant insertion (after bone grafting) were 0.10 mm for immediate implants and 0.02 mm for delayed implants, which did not have a statistically significantly difference (mean difference = 0.08; 95% CI: 0.04 to 0.12; P < 0.001). One year after loading, patients of the immediate group lost on average 0.23 mm and those in the delayed group lost 0.29 mm, the difference being statistically significant (mean difference = -0.06; 95% CI: -0.11 to -0.01; P = 0.036). Patients of both groups were equally satisfied at 4 months as well as at 1 year after loading. CONCLUSIONS: There are more complications with immediate post-extractive implants in comparison to delayed implants. It seems more difficult to obtain an implant insertion torque superior to 35 Ncm in sockets preserved with anorganic bovine bone after a 4-month healing period than with postextractive sites. The aesthetic outcome appears to be similar for both groups.

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.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.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 (P0.001). 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 (P0.001). 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).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.

PURPOSE: To compare the clinical effectiveness of two implant systems: Way Milano and Kentron (Geass, Pozzuolo del Friuli, UD, Italy). MATERIALS AND METHODS: A total of 64 patients requiring at least two single crowns or partial fixed dental prostheses supported by a maximum of three implants had their sites randomised according to a split-mouth design to receive both implant systems at six centres. Patients were followed up for 1 year after initial loading. Outcome measures were: prosthesis/implant failures; any complication; peri-implant marginal bone level changes; and clinician preference. RESULTS: In total 71 Way Milano and 73 Kentron implants were placed. Six patients dropped-out before the 1-year follow-up, but all remaining patients were followed up to 1 year post-loading. No Way Milano implant failed, whereas three Kentron implants failed before loading. Two complications were reported, one for each implant type. There were no statistically significant differences for prosthesis/implant failures (difference in proportions = 0.05, P = 0.25; 95% CI -0.02 to 0.13) and complications (difference in proportions = 0, P = 1.0, 95% CI -0.07 to 0.07) between the implant systems. Three operators preferred Way Milano implants whereas the other three had no preference. At implant placement (baseline) bone levels were higher for Way Milano implants (0.27 mm) than for Kentron implants (0.41 mm). Both groups gradually lost statistically significant amounts of periimplant marginal bone at 4 months after loading and at 1 year after loading. One year after loading, Way Milano implants lost an average of 0.73 mm peri-implant bone compared with 0.84 mm of Kentron implants. Marginal bone level changes were not statistically significant different for Way Milano compared to Kentron implants at 4 months (-0.16 mm, 95% CI -0.30, 0.01; P = 0.0606) and 1 year (-0.09 mm, 95% CI -0.26, 0.09; P = 0.3407) after loading. CONCLUSIONS: No statistically significant differences were observed between the two implant types, although three Kentron implants failed versus none of the Way Milano type. Longer follow-up of wider patient populations are needed to better understand whether there is an effective advantage with one of the two implant designs. Conflict of interest statement: This trial was partially funded by Geass (Pozzuolo del Friuli, UD, Italy), the manufacturer of the implants evaluated in this investigation. However, the 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.

PURPOSE: To compare the clinical outcome of fixed prostheses supported by 4- to 8-mm-long implants with prostheses supported by longer implants placed in vertically augmented atrophic mandibles after a follow-up of 5 years in function. MATERIALS AND METHODS: The Cochrane Central Register of Controlled Trials (CENTRAL) and MEDLINE were searched up to 1st September 2018 for randomised controlled trials (RCTs) with a follow-up of at least 5 years in function comparing fixed prostheses supported by 4- to 8-mm-long implants with prostheses supported by longer implants placed in vertically augmented atrophic mandibles. Outcome measures were prosthesis failure, implant failures, augmentation procedure failures, complications, and peri-implant marginal bone level changes. Screening of eligible studies, assessment of the risk of bias and data extraction were conducted in duplicate and independently by two review authors. The statistical unit of the analysis was the prosthesis. Results were expressed as random-effects models using mean differences for continuous outcomes and risk ratios (RR) for dichotomous outcomes with 95% confidence intervals (CIs). RESULTS: Four eligible RCTs that included originally 135 patients were included. Two RCTs had a parallel-group design and two a split-mouth design. Short implants were 5.0 to 6.6 mm long and were compared with longer implants placed in posterior mandibles augmented with interpositional blocks of bone substitutes. All trials were judged at unclear risk of bias. Twelve (14%) bone augmentation procedures failed to achieve the planned bone height to allow placement of implants with the planned length. Five years after loading, 28 patients (21%) had dropped out from the four RCTs. There were no differences for patients having prosthesis (RR = 1.46; 95% CI: 0.52 to 4.09; P = 0.47; I2 = 0%) or implant (RR = 1.00; 95% CI: 0.31 to 3.21; P = 1.00; I2 = 0%) failures between the two interventions, but there were more patients experiencing complications (RR = 4.72; 95% CI: 2.43 to 9.17; P < 0.00001; I2 = 0%) and peri-implant marginal bone loss (mean difference = 0.60 mm; 95% CI: 0.36 to 0.83; P < 0.00001; I2 = 45%) at longer implants in augmented bone. CONCLUSIONS: Five years after loading, prosthetic and implant failures were similar between the two interventions, but complications and peri-implant marginal bone loss were higher and more severe at longer implants placed in vertically augmented mandibles. Larger trials and longer follow-ups up to 10 years after loading are needed to confirm or reject the present preliminary findings. However in the meantime short implants could be the preferable option.

This case report describes the minimally invasive full fixed rehabilitation of a totally edentulous severely atrophic mandible. The patient refused to undergo any other treatment, from the reconstructive surgery to the removable prosthesis, and asked for a fixed minimally invasive solution in the shortest possible time. Considering that the posterior mandibular bone was inadequate in height and that the interforaminal bone was only 4.3 to 5 mm in height, the patient received four 4-mm-ultrashort implants in the interforaminal area that were immediately loaded. Within all the limitations of this case report this procedure in this specific case appears successful through 2 years of loading.

Background: Short implants (up to 5-mm long) have shown good results when compared to longer implants placed in augmented bone. Purpose: To evaluate if 4-mm ultrashort implants could also be an alternative to bone augmentation in the severely atrophic posterior jaws. The primary aim of the study was to compare implant survival rates between study groups. Materials and Methods: Eighty partially edentulous patients with posterior atrophic jaws (5–6 mm of bone above the mandibular canal and 4–5 mm below the maxillary sinus) were included: 40 patients in the maxilla and 40 in mandible. The patients were randomized to receive one to three 4-mm ultrashort implants or one to three implants at least 10-mm long in augmented bone. Results are reported 5 years after loading with the following outcome measures: implant and prosthetic failures, complications and peri-implant marginal bone level changes. Results: Thirty-two complications were reported for the control group in 18 patients versus 13 complications in 10 patients in the test group, the difference being not statistically significant (p= 0.103). In the augmented group, 12 implants failed in 6 patients versus 7 short implants in 6 cases, and 9 prostheses failed in the control group while 4 in the test one, without statistically significant differences (p= 1.000 and 0.363, respectively). At 5 years after loading, short implants lost on average 0.58 ± 0.40 mm of peri-implant marginal bone and long implants 0.99 ± 0.58 mm, the difference was statistically significant (p= 0.006). Conclusion: Four-millimeter ultrashort implants showed similar if not better results when compared to longer implants placed in augmented jaws 5 years after loading. For this reason, their use could be in specific cases preferable to bone augmentation since the treatment is less invasive, faster, cheaper and associated with less morbidity. However, longer follow-ups and larger trials are needed.

The aim of this retrospective study was to evaluate clinical and radiographic outcomes of guided bone regeneration (GBR) procedures in the rehabilitation of partially edentulous atrophic arches. A total of 58 patients were included with a follow-up of 3 to 7 years after loading. Data seem to indicate that GBR with nonresorbable membranes can be a good clinical choice and suggest that it could be used to vertically reconstruct no more than 6 mm of bone in the posterior mandible. However, this technique remains difficult and requires expert surgeons.

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. Conflict of interest statement: Biomet 3i, manufacturer of the implants used in this investigation, partially supported this trial. However data properties belonged to the authors and by no means did Biomet 3i interfere with the conduct of the trial or the publication of the results.

Purpose: A novel technique to perform safe osteotomies during inlay block regenerative procedures in the posterior atrophic mandible is described. Material and Methods: A 52-year-old male patient with vertical atrophy of the left posterior mandible was treated adopting an inlay block “sandwich” technique using an allogenic cancelous block and a mixture of mineralized and demineralized human bone allograft in putty form as graft. The horizontal osteotomy for the lifting of the osteotomized bone segment was performed using a template prepared from a virtual anatomical replica of the patient's mandible obtained from cone beam computed tomography data. In the second surgical phase, 3 months after the augmentation, 2 implants were easily placed. Results: The horizontal osteotomy was carried out, with no risk, very close to the nerve structures after the precise osteotomy line established preoperatively on the three-dimensional computed tomography (3D-CT) virtual reconstruction. No neurological complications were observed in the first days after the procedure, and no subsequent problems were recorded during the 3-month healing period. Conclusion: Radiographic evaluations and complication-free clinical healing demonstrate the effectiveness of this technique to obtain safe and precise osteotomies.

PURPOSE: To compare the efficacy of 1-stage versus 2-stage lateral maxillary sinus lift procedures. MATERIALS AND METHODS: Sixty partially edentulous patients requiring 1 to 3 implants and having 1 to 3 mm of residual bone height and at least 5 mm bone width below the maxillary sinus, as measured on CT scans were selected. They were randomised according to a parallel group study design into two equal arms to receive either a 1-stage lateral window sinus lift with simultaneous implant placement or a 2-stage procedure with implant placement delayed by 4 months, using a bone substitute in three different centres. Implants were submerged for 4 months, loaded with reinforced provisional prostheses, which were replaced, after 4 months, by definitive prostheses. Outcome measures, assessed by masked assessors, were: augmentation procedure failures; prosthesis failures and implant failures; complications; and marginal peri-implant bone level changes. Patients were followed up to 1 year after loading. Only data of implants placed in 1 to 3 mm of bone height were reported. RESULTS: Two patients dropped out from the 1-stage group and none from the 2-stage group. No sinus lift procedure failed in the 1-stage group but one failed in the 2-stage group, the difference being not statistically significant (P = 1.00). Two prostheses failed or could not be placed in the planned time in the 1-stage group and one in the 2-stage group, the difference being not statistically significant (P = 0.51). Three implants failed in three patients of the 1-stage group, versus one implant in the 2-stage group, the difference being not statistically significant (P = 0.28). Two complications occurred in the 1-stage group and one in the 2-stage group, the difference being not statistically significant (P = 0.61). One year after loading, 1-stage treated patients lost an average of -1.01 mm (SD: 0.56) of peri-implant bone and 2-stage sites about -0.93 mm (SD: 0.40). There were no statistically significant differences in bone level change between groups 1 year after loading (-0.08 mm 95%CI: -0.33 to 0.18 P = 0.56). CONCLUSION: No statistically significant differences were observed between implants placed according to 1- or 2-stage sinus lift procedures. However this study may suggest that in patients having residual bone height between 1 to 3 mm below the maxillary sinus, there might be a slightly higher risk for implant failures when performing a 1-stage lateral sinus lift procedure.

PURPOSE: To evaluate whether 5-mm short dental implants could be an alternative to augmentation with anorganic bovine bone and placement of at least 10-mm long implants in posterior atrophic jaws. MATERIALS AND METHODS: Fifteen patients with bilateral atrophic mandibles (5 mm to 7 mm bone height above the mandibular canal) and 15 patients with bilateral atrophic maxillae (4 mm to 6 mm bone height below the maxillary sinus), and bone thickness of at least 8 mm, were randomised according to a split-mouth design to receive one to three 5-mm short implants or at least 10-mm long implants in augmented bone. Mandibles were vertically augmented with interpositional bone blocks and maxillary sinuses with particulated bone via a lateral window. Implants were placed after 4 months, submerged and loaded, after another 4 months, with provisional prostheses. Four months later, definitive provisionally cemented prostheses were delivered. Outcome measures were: prosthesis and implant failures; any complication and peri-implant marginal bone level changes. RESULTS: In five augmented mandibles, the planned 10-mm long implants could not be placed and shorter implants (7 mm and 8.5 mm) had to be used instead. Three years after loading, two patients, one treated in the mandible and one in the maxilla, dropped out. Three prostheses (1 mandibular and 2 maxillary) failed in the short implant group versus none in the long implant group. In mandibles, one long implant failed versus two short implants in 1 patient. In maxillae, one long implant failed versus three short implants in 2 patients. There were no statistically significant differences in the failures. Eight patients had 13 complications at short implants (1 patient accounted for 6 complications) and 11 patients had 13 complications at long implants. There were no statistically significant differences in complications (P = 0.63, difference = 0.10, 95% CI from -0.22 to 0.42). Three years after loading, patients with mandibular implants lost on average 1.44 mm at short implants and 1.63 mm at long implants of peri-implant marginal bone. This difference was not statistically significant (difference = 0.24 mm; 95% CI -0.01, 0.49 P = 0.059). In maxillae, patients lost on average 1.02 mm at short implants and 1.54 mm at long implants. This difference was statistically significant (difference = 0.41 mm; 95% CI 0.21, 0.60, P = 0.001). CONCLUSIONS: Three years after loading, 5-mm short implants achieved similar results as longer implants in augmented bone. Short implants might be a preferable choice to vertical bone augmentation, especially in mandibles, since the treatment is faster and cheaper, however there are still insufficient data on the long-term prognosis of short implants.

OBJECTIVES: To compare the effectiveness of onlay bone blocks of equine origin (test or XB group) with autogenous bone blocks (control or AB group) harvested from the ramus or the iliac crest for the rehabilitation of partially or fully edentulous atrophic jaws with implant supported prostheses. MATERIALS AND METHODS: Forty patients with partially or fully edentulous atrophic jaws having less than 5 mm of residual crestal bone height and/or less than 3 mm of bone thickness, as measured on computerised tomography (CT) scans, were randomised into two groups according to a parallel group design, either to be augmented with autogenous onlay bone blocks (20 patients; AB group) from the mandibular ramus or the iliac crest, or with onlays blocks of spongious bone of equine origin (20 patients; XB group). Two centres treated 20 patients each. Six XB blocks were modelled on lithographic models of the jaws before grafting. The blocks were fixed with screws and osteosynthesis plates and were covered with resorbable barriers made of equine cortical bone and fixed with tacks. The autogenous bone grafts were left to heal for 4 months and the xenografts for 7 months before placing implants, which were submerged. After 4 months, either bar-retained overdentures or provisional reinforced acrylic prostheses were delivered. Provisional prostheses were replaced, after 4 months, by definitive fixed prostheses. Outcome measures were: prosthesis and implant failures; complications; patient satisfaction; pain recorded 3 and 10 days post-augmentation; number of days of hospitalisation, total and partial infirmity days. All patients were followed for 4 months after loading. RESULTS: All patients could be rehabilitated with implant-supported prostheses and none dropped out. Twenty-eight patients were augmented in the maxilla (15 with AB and 13 with XB) and 12 in the mandible (5 with AB and 7 with XB). No AB graft failed totally versus 10 XB grafts (difference = 0.5; 95% CI 0.23 to 0.68; P = 0.0004). In particular, all 7 XB mandibular grafts and 5 out of 6 XB blocks (3 in mandibles and 2 in maxillas), which were previously modelled on lithographic models of the jaws failed. One implant failed in one AB patient versus 11 implants in 4 XB patients (P = 0.3416). All but 1 prostheses were loaded in time in the AB patients, versus 4 prostheses which were loaded with delays in XB patients because of graft and implant failures (P = 0.3416). Four complications occurred in 4 AB patients versus 15 complications in 12 XB patients (difference = 0.4; 95% CI 0.09 to 0.63; P = 0.0225). Fourteen AB patients reported moderate pain 3 days postoperatively versus 6 XB patients (P = 0.0562); at 10 days, 10 AB patients reported moderate pain versus 1 XB patient (difference = -0.45; 95% CI -0.65 to -0.17; P = 0.0033). The 14 patients harvested from the iliac crest were hospitalised for an average of 3.1 nights, whereas 7 patients treated with XB were hospitalised on average for 1.4 nights (P