Fracture incidence in implant retained mandibular overdenture constructed by either conventional method or CAD/CAM technology- A one year follow up.

Abstract
Purpose: To compare clinically the fracture incidence in overdentures constructed by CAD/CAM technology and compare it with those overdentures constructed by conventional heat cured methods in mandibular overdentures retained by two implants.
Materials and Methods: Twenty completely edentulous patients were participated in this study. The patients were randomly allocated to two equal groups of patients (Group A and group B). Group A patients received complete dentures constructed by conventional heat cured technique. Group B patients received complete dentures constructed by CAD/CAM technology. All the patients received two root form implants bilaterally in the canine regions following delayed loading protocol. Locator attachment was then used to retain the overdenture after 3 months healing period. Overdenture fracture was evaluated for the next 12 month after implant loading.
Results: Only two overdentures from the conventional overdenture group (group A) experienced fracture at area near to the abutment. Chi-square test indicted that, there is no significant differences in the fracture incidence between the study groups after 12 months observation period (P> 0.05).
Conclusion: The incidence of overdenture fractures was not significantly different between overdentures constructed by CAD/CAM or conventional heat curing techniques. When fractures take place, they tended to be in areas close to the abutment.