: Implant supported overdenture is a first treatment choice with high rate of succes to improve oral function , esthetics, inhance masticatory performance and patient,s satisfaction. Bite force is one indicator of the functional state of the masticatory system that results from action of jaw elevator muscles modified by Cranio-mandibular biomechanics.
Objective: The purpose of the present study was to evaluate the effect of increase implant number from two to four implants on maximum bite force.
Material and methods: sixteen patients with upper and lower edentulous ridge participated in this study. Patients were rehabilitated with two or four implant retained overdentures. Patients were randomly divided in to two groups. Group (A): patients had received two implants retained overdentures.Group (B): patients had received four implants retained overdentures. Implants were inserted in mandibular canine area bilateraly in group (A) and in mandibular canine and first premolar area bilateraly in group (B). After three months, bar was attached to the implants. The lower overdenture was picked up intraoraly. The biting force was evaluated by using Loadstar sensor device which was placed in the premolar molar area in right and left side. Patients were instructed to bite on the top of the sensor and the biting force values were displayed on a computer connected to the device.