Prognosis of implants and abutment teeth under combined tooth-implant-supported and solely implant-supported double-crown-retained removable dental prostheses




Objective of this study was to evaluate the incidence of complications in dental implants and abutment teeth used for combined tooth-implant- and solely implant-supported double crown-retained removable dental prostheses (RDPs).

Material and methods

Patients were selected from a prospective clinical study. Seventy-three RDPs retained by 234 implants and 107 abutment teeth were placed in 39 men and 22 women with a mean age of 65 years. Forty-five RDPs were located in the maxilla and 28 in the mandible. Thirty-four RDPs were solely implant-supported and 39 were combined tooth-implant-supported. Kaplan–Meier analysis was used to estimate success defined as survival without severe abutment-related complications, and Cox regression was used to isolate the most relevant prognostic risk factors.


After a median observation period of 2.7 years for the RDPs, six implants failed and eleven implants were diagnosed with peri-implantitis. Four abutment teeth were extracted, and three abutment teeth showed severe complications requiring extended interventions. For both abutment teeth and implants, Kaplan–Meier analyses revealed a 5-year probability of success of 85% for solely implant-supported RDPs and 92% for combined tooth-implant-supported RDPs. Multiple Cox regression identified RDP location (= 0.01), age (= 0.01), and gender (= 0.04) as prognostic risk factors for severe implant-related complications. Solely implant-supported RPDs showed a poorer prognosis, but the risk difference did not reach statistical significance.


Preliminary data suggest that the combination of teeth and implants to support double crown-retained RDPs may result in a prognostic advantage. The present findings should be validated in independent studies.