Long-term survival analysis of standard-length and short implants with multifunctional abutments

Background Spherical shape and connecting bypass screw of the OT Equator abutment (Rhein83, Italy) provides several retentive possibilities, even in non-parallel implants. Objective This study assessed the long-term survival of standard-length and short implants receiving this multifunctional abutment. Methods Partially, edentulous patients (44 males and 64 females) (mean age 58.2 +/- 10.5 years) rehabilitated with a fixed implant-supported prosthesis where the OT Equator abutments (Rhein83) were applied. Follow-up evaluations were performed up to 5 years following prosthesis delivery. Kaplan-Meier survival analysis and Cox regression analysis were used to determine whether the distribution of time to failure differed based on implant characteristics (length and region), adjusting for sex (alpha = 0.05). Results In total, 216 implants (5 x 8 mm, n = 126; 5 x 6 mm, n = 90) (Betwice, Mech & Human, Italy) were installed. The average follow-up period was 25.3 months (+/- 19.3 months). Eight failures occurred, with most observed before loading (n = 6). Cumulative survival rates (CSR) at implant and abutment levels were 94.3% and 97.1%, respectively. Regarding implant length, CSRs were 97.8% and 90.6% for short and standard-length implants, respectively, with no difference between subgroups (logrank: chi(2) = 1.34, df = 1, P = 0.25). No significant difference was also found between implants of maxilla (CSR = 92.2%) and mandible (CSR = 95.5%; logrank: chi(2) = 0.08, df = 1, P = 0.78). Conclusion The OT Equator abutment (Rhein83) showed a stable clinical performance, with continuous and predictable survival.