Bone rebuilding was one of the surgeons’ motivations from the past. The purpose of this study was biomechanics evaluate the effect of sodium fluoride and phenytoin on cancellousbone defect healing in rat model.The experiment was conducted on 40 male adult SD rats which were divided into eight groups of control and experiments. After induction of general anesthesia, a hole in size of 2×3 mm in diameter and depth was made using a dental bit in the inner aspect of the between condyles of right femor. In all groups, defect was left untreated. Control group was given water and group II received daily 5 mg/kg/IP of Phenytoin and groups III, IV and V were exposed to fluoridated water at different concentrations (8, 30 and 60 mg F-/L), group VI, VII and VIII received together of daily 5 mg/kg/IP of Phenytoin and fluoridated water at different concentrations (8, 30 and 60 mg F-/L). After 45 days all rats were sacrificed and biomechanical penetration tests of the distal femoral bone were performed. Data were submitted to statistical analysis by variance analysis (ANOVA) at a significance level of 5% (p<0.05).The results show positive effect of phenytoincompared to the control group. Also in the groups receiving fluoride and phenytoin, the best result is related to the group receiving 30 mg. And increase the amount of fluoride causes a negative impact the compressive strength of the bone healing.The results of this study show that fluoride level at 30 mg F-/L in drinking water and 5 mg/kg phenytoin increases compressive strength of cancellous bone defect in healing process and could stimulate osteogenesis in femoral cancellous bone defect in rats.
