Clinical and radiographic outcomes of implant-supported fixed dental prostheses with cantilever extension. A retrospective cohort study with a follow-up of at least 10 years.

Abstract

To report the clinical and radiographic outcomes of implant-supported fixed dental prostheses with cantilever extensions (FDPCs) after a function time ≥10years. Patients with FDPCs in posterior areas were clinically and radiographically re-evaluated. Mesial and distal radiographic marginal bone levels (mBLs) from baseline (i.e. delivery of FDPC) to the follow-up examination were calculated and compared between implant surfaces adjacent to and distant from the cantilever extension. Implant survival rate, pocket probing depth (PPD), presence/absence of bleeding on probing (BoP) and presence/absence of mechanical/technical and biological complications were recorded. Twenty-six patients with 30 FDPCs supported by 60 implants were re-evaluated after a mean loading time of 13.3±2.7years (range: 10-18.6years). One diameter-reduced implant carrying a cantilever extension fractured, yielding a patient-based survival rate of 96.2% (95% CI: 0.95/1.0). The mean marginal bone level change was not statistically significantly different from baseline to follow-up (1.2mm±0.9 to 1.6mm±1.7; 95% CI: -0.1/0.9; p>.05). The mean PPD changed statistically significantly from 3.4mm±0.7 to 3.7mm±0.7 (95% CI: 0.04/0.6; p=.02). Loss of retention occurred≥1x in 9 patients (34.6%, 95% CI: 0.44/0.83). At follow-up, peri-implant health was diagnosed in 12 (46.2%), peri-implant mucositis in 7 (26.9%) and peri-implantitis in 7 (26.9%) patients, respectively. Despite a high rate of loss of retention, the use of implant-supported FDPCs in posterior areas represents a reliable long-term treatment option with a high implant survival rate and minimal peri-implant bone level changes irrespective of the location of the cantilever extension.