Effect of the number and localization of implants placed in the atrophic mandible on the fragility of the symphysis region.

BACKGROUND

Implant-supported overdenture prostheses are the preferred treatment option for rehabilitating patients with atrophic edentulous conditions. However, limited research has examined the impact of these implant applications on the structural endurance of the mandible, which is already compromised due to atrophy, particularly when subjected to frontal traumatic forces. This study aimed to evaluate the effects of traditional full dentures, two-implant, and three-implant-supported overdenture prosthesis systems in atrophic, fully edentulous mandibles on their resistance to frontal traumatic forces.

METHODS

A computer-generated model of an atrophic mandible was developed. Five different treatment models were simulated using computer software: traditional full dentures, two-implant-supported locator attachment overdenture prostheses, two-implant-supported bar attachment overdenture prostheses, three-implant-supported locator attachment overdenture prostheses, and three-implant-supported bar attachment overdenture prostheses. Static linear analyses were performed by applying a 2000-N force over a circular area (1 cm in diameter) perpendicular to the frontal plane from the symphysis region in all models. Principal stress and von Mises stress values on the mandible were subsequently analyzed.

RESULTS

The highest tensile stress was observed in the three-implant locator attachment-supported overdenture prosthesis model, whereas the lowest tensile stress was recorded in the conventional full denture model. The highest compressive stress was found in the three-implant bar attachment overdenture prosthesis model. The findings indicate that the use of locator attachments reduces the mandible’s resistance to both tensile and compressive stresses, whereas bar attachments provide a safer alternative by enhancing structural stability.

CONCLUSION

The findings of the study underscore the importance of selecting an appropriate prosthesis type to optimize stress management and mitigate fracture risk in atrophic mandibular models. Further research is needed to evaluate the biomechanical strength of the mandible under various force conditions.