Wide-diameter implants: analysis of clinical outcome of 304 fixtures.

Background: In the last decade, the use of wide-diameter implants (WDIs; diameter > 3.75 mm) has increased. Although good clinical outcomes have been reported in recent literature, there are few reports on this topic. Thus, we planned a retrospective study on a large series of WDIs to evaluate the clinical outcome. Methods: From October of 1996 to December of 2004, 205 patients were operated on, and 304 WDIs were inserted. The mean postloading follow-up was 30 months. Implant diameter and length ranged from 5.0 to 6.5 mm and from 8.0 to 15 mm, respectively. Because only five of 304 implants were lost (i.e., a survival rate of 98.4%) and no statistical differences were detected among the studied variables, no or reduced crestal bone resorption (CBR) was considered an indicator of success to evaluate the effect of several host-, surgery-, and implant-related factors. A general linear model (GLM) was performed to detect variables that were associated statistically with CBR. Results: Only five of 304 WDIs were lost, and no differences were detected among the studied variables. On the contrary, the GLM showed that distal teeth (i.e., premolars and molars), small implant diameter (i.e., 5.0 and 5.5 mm), and short implant length (i.e., < 13 mm) correlated with a statistically significant lower CBR. Conclusion: The use of WDIs is a viable treatment option, and it may provide benefits in posterior regions for long-term maintenance of various implant-supported prosthetic rehabilitations.