Comparison of stresses transferred to the implant supported overdentures with bar, ball and zaag attachments through photoelasticity Dr. A. Saboori* - Dr. Gh. Esfahanizade** - Dr. M. Ejlali*** *- Assistant Professor of Prosthodontics Dept. - Faculty of Dentistry – Shaheed Beheshti University of Medical Sciences. **- Assistant Professor of Prosthodontics Dept. - Faculty of Dentistry – Tehran Islamic Azad University. ***- Professor and Chief of Prosthodontics Dept. - Faculty of Dentistry – Shaheed Beheshti University of Medical Sciences. Background and Aim: When a complete denture is replaced with an overdenture supported by implant, masticatory efficiency will be improved. There are a lot of controversies on the use of the best attachments in overdentures. The aim of this study was to compare the stresses transferred to the implant supported overdentures in mandible with bar, ball and zaag attachments using photoelastic technique. Materials and Methods: In this descriptive in – vitro study, stresses transferred to the implants supported overdentures with bar, ball and zaag attachments were analyzed using photoelastic method. Two implants were installed in the canine area 8 mm from the midline. Vertical and oblique loads of 30Ib were applied to the first molar unilaterally. Resultant stress distribution with ball, bar and zaag attachments were evaluated. Results: The bar attachments exhibited the most stress transferred to the implants on the loaded side and opposite side. When the model was subjected to the posterior vertical load. The oblique load transferred to the implants was more than the vertical load. The ball and zaag attachments transferred the vertical load to both implants and edentulous area. These both attachment systems exhibited more stress on implants in oblique load where as the edentulous ridge was stress free. Conclusion: Bar attachments transferred more stress to the implant bodies than ball and zaag attachments in both oblique and vertical loads and zaag attachments transferred more stress to the implant as compared with the ball ones. Key words: Implant - Overdentures - Attachment - Ball - Bar - Zaag – Photoelasticity |
