Short (8-mm) locking-taper implants supporting single crowns in posterior region: a prospective clinical study with 1-to 10-years of follow-up.

The aim of this study was to evaluate the long-term outcome of short (8-mm) locking-taper implants supporting single crowns in the posterior regions and to analyze the influence of different factors on implant survival and implant-crown success rates. Between June 2002 and September 2011, all patients referred to two private practices for treatment with short (8-mm) implants supporting single tooth restorations in posterior areas of both jaws were considered for inclusion in this study. At each annual follow-up session, clinical and radiographic parameters were assessed. Implant-crown success criteria included absence of pain, suppuration, mobility, and peri-implant radiolucency, distance between the implant shoulder and the first visible bone-to-implant contact (DIB) <1.5 mm after 12 months and not exceeding 0.2 mm for each following year, absence of prosthetic complications. The cumulative survival and implant-crown success were assessed using the Kaplan-Meier survival estimator; Chi-square test was applied to evaluate correlations between the study variables. The statistical analysis was performed at the patient and at the implant level. Two hundred and fifteen implants (124 maxilla; 91 mandible) were placed in 194 patients (104 men; 90 women). Three implants failed (2 maxilla; 1 mandible). The 10-year cumulative survival rate was 98.4% (patient-based) and 98.5% (implant-based). Among the surviving implants, the mean DIB was 0.31 (±0.24), 0.43 (±0.29), and 0.62 (±0.31) mm at the 1-, 5-, and 10-year follow-up session; two biologic and three prosthetic complications were reported, for a 10-year cumulative implant-crown success rate of 95.8% (patient-based) and 95.9% (implant-based). The implant survival and implant-crown success rates did not differ significantly with respect to patients' gender, age, smoking habit, parafunctional habit, implant location, implant diameter, and bone type. The use of short (8-mm) locking-taper implants is a predictable treatment modality for the restoration of single tooth gaps of posterior segments of dentition.