Background: This 10-year follow-up study reports denture satisfaction and oral health-related quality of life of edentulous patients treated with two-implant mandibular overdentures. Methods: This is a follow-up of a previous study carried out between 1997-2005. Originally, the patients were randomly divided into two groups: one receiving two-implant mandibular overdentures (IODs) and another, relined mandibular dentures (RCDs). The latter group were offered and accepted IODs at two years, which then became another IOD group. The main outcome variable of this study is patient opinion over time of the IODs. The participants completed a self-administered questionnaire containing demographics, 15 variables of denture satisfaction, and 20 questions of the Oral Health-Related Impact Pro le (OHIP-20). Comparison between groups were made with Mann-Whitney U-tests for denture variables and T-tests for OHIP-20 variables. Changes over time were analysed with multilevel linear models for denture variables and multilevel ordinal regression analyses for OHIP-20 variables. Results: Of the 54 original participants, 29 responded. Disregarding patients who had died at 10 years, this represented a response rate 76%. In the IOD group, the degree of denture satisfaction and OHIP-20 scores remained high and stable over the 10-years period for all but one variable. The RCD group showed a modest improvement of denture satisfaction and OHIP-20 scores for the rst two years. After treatment with IODs, these variables improved at 10 years to the same level as the original IOD group. Conclusions: The positive effect on denture satisfaction and oral health-related quality of life of edentulous patients treated with two-implant mandibular overdenture remains unchanged 10 years after treatment, con rming the advice that this should be the standard treatment for the edentulous mandible.

Abstract Background: This 10-year follow-up study reports denture satisfaction and oral health-related quality of life of edentulous patients treated with two-implant mandibular overdentures. Methods: This is a follow-up of a previous study carried out between 1997 – 2005. Originally, the patients were randomly divided into two groups: one receiving two- implant mandibular overdentures (IODs) and another, relined mandibular dentures (RCDs). The latter group were offered and accepted IODs at two years, which then became another IOD group. The main outcome variable of this study is patient opinion over time of the IODs. The participants completed a self-administered questionnaire containing demographics, 15 variables of denture satisfaction, and 20 questions of the Oral Health-Related Impact Profile (OHIP-20). Comparison between groups were made with Mann-Whitney U-tests for denture variables and T-tests for OHIP-20 variables. Changes over time were analysed with multilevel linear models for denture variables and multilevel ordinal regression analyses for OHIP-20 variables.Results: Of the 54 original participants, 29 responded. Disregarding patients who had died at 10 years, this represented a response rate 76%. In the IOD group, the degree of denture satisfaction and OHIP-20 scores remained high and stable over the 10-years period for all but one variable. The RCD group showed a modest improvement of denture satisfaction and OHIP-20 scores for the first two years. After treatment with IODs, these variables improved at 10 years to the same level as the original IOD group.Conclusions: The positive effect on denture satisfaction and oral health-related quality of life of edentulous patients treated with two-implant mandibular overdenture remains unchanged 10 years after treatment, confirming the advice that this should be the standard treatment for the edentulous mandible. Trial registration: This study was approved by Norwegian Committee for Medical Research Ethics in Norway, Health Region West (2017/618) the 16th of May 2017.