ABSTRACT
PURPOSE: Prosthetic rehabilitation of completely edentulous patients has been traditionally performed with complete dentures for many years. However, patient complaints are reported due to insufficient retention and high mobility of mandibular dentures. Therefore, in these patients, overdenture prostheses, which are usually made by placing at least two implants in the interforaminal region of the mandible, have become widespread. In these prostheses, bar, stud, magnetic, or ball and locator attachments are used. This study aimed to evaluate the stress on mandibles by an overdenture with locator attachments supported by two implants placed on three different bone types in three different regions. MATERIALS AND METHODS: Finite element analysis (3D) was used to design a mandible and overdenture. Two implants and locator attachment systems were placed into the lateral incisor, canine, and premolar regions. In computer-generated mandible and overdenture models, a force of 100 N was loaded obliquely and vertically from the mandibular first molar teeth region; then, the values obtained from the forces were compared. Eighteen analyses were performed with two different loading options in nine different models. Von Mises, compressive, and tensile stress values were analyzed. RESULTS: As the bone type changed from D1 to D3, the stresses on the bone increased in direct proportion. However, with all three bone types, lower tensile values were found in cortical bone in an above-implant removable prosthesis supported by an implant in the lateral incisor region. CONCLUSION: Biomechanically, the lateral incisor and canine regions were more advantageous than the first premolar tooth region in prosthesis designs where two implants were used in all bone types.
