Effect of Different Implants Number and Distributions Used to Assist Mandibular Complete Overdenture: A Study of Bite

: Objective: This within-patient study aimed to evaluate the influence of different numbers and distribution of implants used to assist mandibular complete overdenture on a patient's maximum biting force and masticatory efficiency . Materials and Methods: Six healthy completely edentulous patients were selected for this study. Each patient received a conventional complete denture then four implants were installed in the canine and premolar areas bilaterally. The implants were delayed loaded by mandibular overdenture using locator attachments, patients were classified into Group I: anterior two implants loaded by the overdenture; Group II: posterior two implants loaded by the overdenture; and Group III: four implants loaded with the overdenture, The bite force and the chewing efficiency were evaluated immediately 3 and 6 months after insertion. The exchange of loading between patients was done after each evaluation session. Results: There was a statistically significant difference in bite force and chewing efficiency between conventional complete dentures and implant-assisted overdentures regardless of the number and distribution of the implants after different observation times. The four implant-assisted overdentures showed a statistically significant difference in bite force and chewing efficiency compared with the other groups after all periods of overdenture insertion. Conclusions: Regardless of the implant number and location, implant-retained mandibular overdenture significantly increased the bite force and masticatory efficiency compared with the conventional complete denture. The four implants assisted mandibular overdenture significantly increased the bite force and masticatory efficiency compared with only two implants in the canine or premolar areas.