Complications and survival rates of 55 metal-ceramic implant-supported fixed complete-arch prostheses: A cohort study with mean 5-year follow-up

Abstract

Statement of problem: Long-term outcomes with metal-ceramic (MC) implant-supported fixed complete dental prostheses (IFCDPs) are scarce.

Purpose: The purpose of this retrospective study was to assess the rate of biologic and technical complications in a cohort of edentulous patients treated with MC IFCDPs by residents after a mean clinical follow-up of 5 years (range: 1 to 12 years).

Material and methods: Forty-one participants with 55 MC IFCDPs underwent a single-visit comprehensive examination that included a medical and dental history review and clinical and radiographic examinations. All supporting implants and prostheses were examined for biologic and technical complications. Life table analysis and Kaplan-Meier survival curves were calculated.

Results: Of 359 moderately rough surface dental implants, 2 had failed in 1 patient after 11 years of functional loading, yielding a cumulative implant survival rate of 99.4%. Owing to the implant failure, 1 of 55 edentulous arches restored with IFCDPs failed, yielding a cumulative prosthesis survival rate of 98.2% after mean observation period of 5.0 years. Soft tissue recession was the most frequent minor biologic complication (annual rate 7.8% at the prosthesis level) for both cement and screw-retained IFCDPs (group C and S), and peri-implantitis (annual rate 1.6% at the implant level) the most frequent major biologic complication. Wear of porcelain (annual rate 8.0% at the prosthesis level) was the most frequent minor technical complication for both groups, and fracture of porcelain (annual rate 0.8% at the dental-unit level) was the most frequent major technical complication. Minor complications were the most frequent in both the groups (cement and screw retained).

Conclusions: High implant and prosthesis survival rates (above 98%) were achieved, yet substantial complication rates were encountered. The most frequent major biologic complication was peri-implantitis, with a 5-year implant-based rate of 8% (95% confidence interval [CI]: 5.8-11.1), whereas the most frequent major complication was fracture of porcelain with a 5-year dental unit-based rate of 4%. The estimated cumulative rates for "prosthesis free of biologic complications" were 50.4% (95% CI: 36.4% to 63.0%) at 5 years and 10.1% (95% CI: 3.5% to 20.8%) at 10 years, whereas for "prosthesis free of technical complications," they were 56.4% (95% CI: 41.7% to 68.8%) at 5 years and 9.8% (95% CI: 3.2% to 21.0%) at 10 years.