International Journal of Oral Implantology, 01/2011

Aim: To compare the clinical and radiological outcomes of 1- versus 2-stage implant placement. Materials and methods: Forty-seven patients were randomly allocated to 1- or 2-stage treatment groups immediately after implant placement. Twenty-nine patients received 38 1-stage early loaded implants and 18 patients received 51 2-stage early loaded implants. Outcome measures were failures of implants and/or prosthesis, complications, pain score, amount of analgesic consumption and periimplant bone level changes at implant loading (12 weeks) and at the 1-year follow-up. Results: After 1 year, no dropout occurred. In the 1-stage group, 2 implants (1 patient) failed to osseointegrate and the implant-supported prosthesis could not be placed, versus none in the 2-stage group. Two complications were reported in the 1-stage group versus only one in the 2-stage group. Pain score measurements, analgesic consumption and peri-implant bone level did not show any significant difference between the two groups. All patients would undergo the same procedures again. Conclusions: The submerged technique is not a prerequisite for osseointegration, though 1-stage implant placement might be at a slightly higher risk for early failures. Keywords: bone crest level, dental implants, early loading, one-stage placement, two-stage placement

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 (5-7 mm bone height above the mandibular canal), and 15 patients with bilateral atrophic maxillae (4-6 mm bone height below the maxillary sinus) and bone thickness of at least 8 mm, were randomised according to a splitmouth 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 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 5 augmented mandibles, the planned 10 mm long implants could not be placed and shorter implants (7 and 8.5 mm) had to be used instead. One year after loading no patient dropped out. Two long (8.5 mm in the mandible and 13 mm in the maxilla) implants and one 5 mm short maxillary implant failed. There were no statistically significant differences in failures or complications. Patients with short implants lost on average 1 mm of peri-implant bone and patients with longer implants lost 1.2 mm. This difference was statistically significant. Conclusions: This pilot study suggests that 1 year after loading, 5 mm short implants achieve similar if not better results than longer implants placed in augmented bone. Short implants might be a preferable choice to bone augmentation since the treatment is faster, cheaper and associated with less morbidity, however their long-term prognosis is unknown. Keywords: bovine anorganic bone, inlay graft, short dental implants, sinus lift, vertical augmentation

Purpose: To compare the efficacy of three different antibiotic regimens in reducing early dental implant failure. Materials and methods: In a controlled clinical trial, 270 consecutively treated patients were allocated to three antibiotic groups, alternatively, according to order of participation in the trial: Group A (2 g amoxicillin single preoperative dose), Group B (single preoperative 2 g amoxicillin followed by 500 mg three times daily for 5 days) and Group C (postoperative amoxicillin with clavulanic acid 625 mg three times daily for 5 days). Outcomes were pain, wound infection, dehiscence, adverse events possibly related to antibiotics and early implant failure. The patients were followed postoperatively at 1 week, 1 month and at the beginning of the prosthetic stage. Chi-square test and ANOVA test were used to examine differences. Results: In total, 240 patients were adherent to the trial protocol: Group A, 73 patients (210 implants); Group B, 79 patients (266 implants); and Group C, 88 patients (290 implants). Patients experiencing early implant failure: 12 in Group A (16.4%), 11 in Group B (13.9%) and 13 in Group C (14.8%). No statistically significant differences were observed for any of the outcome measures between the three groups. Conclusions: It may not be necessary to provide postoperative antibiotics in patients undergoing dental implant placement, however, these preliminary findings need to be confirmed by large multicentre clinical trials. Keywords: antibiotic prophylaxis, controlled clinical trial, dental implant, failure

Purpose: To evaluate the influence of cigarette smoking on the survival of dental implants with a retrospective observational study of 5 years. Materials and Methods: A total of 1727 consecutively treated patients at four private practices were divided into non-smokers (NS group, 1178 patients) and smokers (S group; 549 patients) according to what they declared prior to implant placement. Non-smokers received 4460 implants and 2583 implant-supported prostheses, whereas smokers received 2260 implants and 1292 implantsupported prostheses. Various implant systems and procedures were used. Outcome measures were prosthesis and implant survival. Results: Over the 5 years after loading, 159 (17%) non-smokers and 91 (13%) smokers were lost to follow-up; 20 (0.9%) prostheses could not be placed or failed in 15 non-smokers and 12 prostheses (1.2%) could not be placed or failed in 12 smokers. One hundred and twelve (2.9%) implants failed in 105 non-smokers and 107 (5.5%) implants failed in 75 smokers. Most of the implant failures (90%) occurred before implant loading. Fitting a logistic regression for early implant failures and total implant failures, taking into account the clustering of implants in patients, there were no statistically significant differences for prosthesis failures (P value not calculated as too few failures) and early implant failures between the two groups (P = 0.13). However, when considering all implant failures up to 5 years after loading, significantly more failures (5.5%) occurred in smokers compared with non-smokers (2.9%) (OR 1.72; 95% CI 1.20 to 2.50; P = 0.003). Conclusions: Due to the retrospective nature of this study, conclusions have to be interpreted with caution. Five years after loading, smokers experienced almost twice as many implant failures compared with non-smokers. Non-statistically significant trends in favour of non-smokers were observed for early implant failures and prosthesis failures. Keywords: dental implants, prognosis, smoking

Background: There is limited evidence for the outcome of short implants (7 mm) to rehabilitate posterior jaws. Purpose: To report on the outcome of 7 mm short implants in the rehabilitation of posterior areas of atrophic jaws 1 year after loading. Materials and methods: This prospective study included 127 patients treated with 217 implants supporting 165 fixed prostheses. Final abutments were delivered at surgery stage, and in 11 patients (18 implants) a provisional acrylic resin crown or bridge was manufactured and attached to the implants on the same day as the surgery, achieving immediate function. The final prosthesis was typically delivered after 6 months. Outcome measures were implant survival calculated at patient and implant levels, complications and peri-implant marginal bone resorption calculated at patient level. Results: Three patients with 5 implants were lost to follow-up after 7 months. Implant losses occurred in 6 of the 127 patients and 10 of the 217 implants placed failed, giving a success rate of 95% at patient and implant level after 1 year of follow-up. The mean marginal bone resorption after 1 year of follow-up was 1.27 mm (SD = 0.67 mm). The only complication registered was a periimplant pathology at one implant. Conclusions: One year after loading, 7 mm short implants provided good success rates (95% at patient level and implant level) suggesting that the use of short implants is a viable concept, however longer follow-ups are needed to confirm these preliminary results. Keywords: immediate function, one-stage protocol, prospective study, short implants