Assessment of masticatory function of mandibular implant-supported overdenture wearers: A 3-year prospective study.

STATEMENT OF PROBLEM: Wearers of mandibular complete dentures (CDs) often complain of retention and stability problems resulting in poor masticatory function. Evidence suggests that a mandibular overdenture (MOD) stabilized by 2 implants represents the treatment of choice to improve stability and masticatory function. Measurements are needed of the improvement in masticatory function after providing mandibular implant-stabilized overdentures. PURPOSE: The purpose of this prospective clinical study was to evaluate the changes in masticatory function from baseline (T0) to 3 months (T1) and 3 years (T2) in participants with MODs and to assess the effect of baseline mandibular bone height and volume on masticatory function after 3 years. MATERIAL AND METHODS: Participants were assessed for masticatory function by using masticatory performance involving paraffin wax cubes as an objective measure and by using masticatory ability involving a questionnaire as a subjective measure. Edentulous individuals presenting for replacement dentures were provided with conventional mucosa-supported prostheses and evaluated for masticatory function after a 3-month settling-in period (baseline measure). Before implant placement, baseline measures of bone height and volume were recorded from cone beam computed tomography (CBCT) images. The prostheses were then converted to implant-stabilized mandibular overdentures while any maxillary prostheses remained supported by the mucosa. Masticatory function was reassessed at 3 months and 3 years after insertion of the mandibular overdentures, and the mean changes from baseline were analyzed with the Wilcoxon signed-rank test. The effect of variables on masticatory function was determined by using multivariate linear regression analyses. RESULTS: A total of 23 participants were included in the study, with only 1 participant not completing the 3-year assessment. Significant improvement was observed in the masticatory performance (mixing ability index) (P<.01) and masticatory ability score (P<.001) from baseline to 3 months and baseline to 3 years. Bone height and volume had no significant effect on the improvement of masticatory function after conversion to an implant-stabilized mandibular overdenture. CONCLUSIONS: Masticatory function significantly improved after 3 months and was maintained over 3 years in participants with implant-stabilized mandibular overdentures. However, baseline bone height and volume had no significant effect on these changes in masticatory function after 3 years.