Twelve-Year Retrospective Follow-Up of Machined Implants in the Posterior Maxilla: Radiographic and Peri-Implant Outcome Massimo Simion, MD, DDS; Luca Gionso, MD, DDS; ‡ Giovanni Battista Grossi, MD, DDS, DMD; Francesco Briguglio, PhD, DDS; ‡ Filippo Fontana, DDS ABSTRACT Purpose: To retrospectively evaluate the survival rate of machined implants in sinus-lifted posterior maxilla after 12 years, with special reference to radiographic outcome and peri-implantitis. Materials and Methods: From 37 possible candidates, 29 patients with 59 implants were evaluated. Implants were placed in the posterior maxilla in combination with a sinus elevation procedure (27 patients) or 6 months after sinus elevation (2 patients). Marginal bone level changes were radiographically evaluated at baseline and 1, 7, and 12 years post-loading. Probing depth was measured; presence/absence of plaque and bleeding on probing were recorded. Results: Four out of 59 implants failed in 4 out of 29 patients (cumulative survival rate = 93.2%). The mean bone loss was 0.78 mm (1 0.88) after 12 years. Changes in the mean bone level were statistically significant between baseline and all the other follow-up intervals (p < .001). Statistically significant differences could be demonstrated for the first- to 12th-year interval (p < .05) and for the seventh- to 12th-year interval (p < 0.001). No statistically significant differences could be demonstrated at the first- to seventh-year interval (p = .32). The mean overall probing depth was 2.9 1 0.66 mm. Probing depth was moderately correlated with the marginal bone changes at 7 year and after 12 year follow up (p = .05). No signs of peri-implantitis were reported during the 12-year follow-up period. Conclusions: This follow-up demonstrates a very good prognosis when implants with machined surfaces are used. The frequencies of implant failures were very small. Within the limits of the results from this study, the risk of peri-implantitis in the posterior maxilla might be considered a minor problem when implants with machined surfaces are used. KEY WORDS: dental implants, implant survival, long-term follow-up, marginal bone loss, maxillary sinus grafting, peri-implantitis INTRODUCTION Implant treatment is a routine and well-documented procedure for the rehabilitation of partially and totally edentulous patients, as reported by several reviews. 1–3 The results of implant therapy are considered very suc- cessful, as survival rate varies between 85% and 99% worldwide. 1,2,4 In general, maxillary implants have lower success rates compared with mandibular ones. 1,5,6 Dif- ferent reasons have been discussed, but jaw bone quality seems to play an important role. Survival rate decreases when implants are placed in conjunction with sinus floor elevation with the lateral approach, varying between 61.7% and 100%, with an average of 91.8%. 7 In the last 12 years, so-called active implant surfaces have replaced the traditional machined surfaces due to the claim that they provide faster and greater bone-to- implant contact and therefore higher success rates. In 2003, a systematic review on the effect of maxillary sinus ‡ private practice, Milan, Italy Corresponding Author: Professor Massimo Simion, Department of Periodontology, Dental Clinic, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Dipartimento di Scienze Chirurgiche Ricostruttive e Diagnostiche, Università degli Studi di Milano, Viale Tunisia 48, Milano 20124, Italy; e-mail: msimion@studiosimion.it © 2014 Wiley Periodicals, Inc. DOI 10.1111/cid.12236 1