Abstract: Analyzing whether radiographic, functional, and oral health-related quality of life (OHRQoL) outcomes are maintained over 3 years of implant-retained mandibular overdenture (IMO) function and investigating the bite force associations in the 3rd year of function. A longitudinal clinical study in which 24 IMO users were evaluated during a 3-year follow-up period. Patients’ posterior area index, masticatory function, OHRQoL and bite force were assessed. The masticatory function parameter ST_X50 reflects the opening through which 50% of the crushed particles would pass, ST_B describes the homogeneity of the bolus, and the masticatory efficiency parameters ME_5.6 and ME_2.8 represent the % of material retained in the 5.6 and 2.8 mm sieves, respectively. A significant increase in posterior area index (p = .01) was found in all evaluated periods. Minor deteriorations in ST_X50 (p = .01) and ME_5.6 (p = .01) between the 2nd and the 3rd year coincided with improvements in ST_B (p = .01), number of cycles (p = .01), and cycle time (p = .02). The global OHIP-Edent score (p = .02) and the scores in the functional limitation (p = .02), psychological discomfort (p = .01), and handicap domains (p = .01) increased significantly between the 2nd and the 3rd year. Correlations between bite force and cycle time (p = .03) and between posterior area index and ST_X50 (p = .01) and ME_2.8 (p = .02) were also found. Changes in posterior area index, masticatory function, and OHRQoL are still ongoing during the 3rd year of IMO function. Bite force and posterior area index influence the masticatory function outcomes in the 3rd year of IMO function Ver menos