A meta-analysis examining the clinical survivability of machined-surfaced and osseotite implants in poor-quality bone

A frequently cited cause of dental implant failure is the inadequate quality of bone found at the implant site during osteotomy preparation. Although bone quality clearly can affect integration rates, additional variables, such as the implant surface conditioning, can also influence long-term implant performance success. The following report examines outcomes of clinical studies that monitored the performance of machined-surfaced implants and dual acid-etched Osseotite (Implant Innovations, Inc., Palm Beach Gardens, FL) implants isolating the effect of bone quality and implant surface conditioning.

Implant data are derived from eight prospective multicenter clinical studies representing 2614 machined-surfaced implants and 2288 Osseotite implants. All implant placement surgeries followed a two-stage surgical approach with an unloaded healing period of 4 to 6 months. Bone quality was assessed by operator perception of resistance during drilling and ranked as dense, normal, or soft. At the time of this analysis, implant follow-up from placement ranged up to 66 months for the Osseotite and 84 months for the machined-surfaced implants. To isolate the effect of bone quality, other baseline variables were compared to ensure equal distribution between groups. Baseline variables included patient demographics, locations, dimensions of implants, and types of restorative cases. Implant performance was analyzed using nonparametric survival analysis (Kaplan-Meier estimator). Cumulative success rates (CSR) were calculated and differences between implant-bone quality combinations were assessed using the log-rank method.

For the machined-surfaced implants, the 4-year CSR in all bone sites is 92.7%. For the implants placed in good (dense and normal) bone, the 4-year CSR is 93.6% compared with the 4-year CSR in poor (soft) bone of 88.2% (P < 0.05). For Osseotite implants in all sites, their overall 4-year CSR was 98.4%, 98.4% in good bone, and 98.1% in poor bone.

Bone quality therefore seems to have a definitive impact on machined-surfaced implants, but this effect was not observed in the Osseotite implant series.