CLINICAL RESEARCH Assessment of masticatory function of mandibular implant- supported overdenture wearers: A 3-year prospective study Taimur Khalid, BDS, MDSc, MClinDent, MProsRCSed, a Norsiah Yunus, BDS, MSc, b Norliza Ibrahim, BDS, MSc, PhD, c Nosizana Binti Mohd Saleh, DDS, PhD, d David Goode, BSc(Hons), BChD, Grad Dip, e and Mohd Masood, BDS, MSc, DDPH, PhD f Wearers of mandibular complete dentures (CDs) often complain of retention and stability problems. 1-3 Their masticatory function is also markedly reduced compared with dentate individuals, 4 requiring up to 7-times more mastication strokes to reduce their food to half of its original size. 5 After removal of teeth, the mandibular ridge provides a reduced surface area to support a complete denture Supported by the University of Malaya, Malaysia (research grant no.: PG221-2015A). a Graduate student, Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia. b Professor, Department of Restorative Dentistry, Faculty of Dentistry University of Malaya, Kuala Lumpur, Malaysia. c Senior Lecturer, Department of Oral and Maxillofacial Clinical Sciences, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia. d Senior Lecturer, Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia. e Senior Lecturer, Department of Dentistry and Oral Health, La Trobe University, Bendigo, Australia. f Senior Lecturer, Department of Dentistry and Oral Health, La Trobe University, Bendigo, Australia; and Adjunct Professor, Department of Community Dentistry, Dental Institute, University of Turku, Turku, Finland. ABSTRACT 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 (J Prosthet Dent 2019;-:---) THE JOURNAL OF PROSTHETIC DENTISTRY 1