Photoelastic stress analysis in a pier retainer of an anterior resin-bonded fixed partial denture

Abstract

Statement of problem. A clinical situation may arise with 2 edentulous spaces and a single intact pier tooth. A dentist may restore these edentulous spaces with a long span resin-bonded fixed partial denture using the pier and the 2 terminal abutments for bonding. Purpose. This study analyzed the stresses induced in a pier retainer of an anterior resin-bonded fixed partial denture and determined the effect on a pier abutment. Material and methods. Photoelastic materials were selected to represent the relative stiffness of 3- and 5-unit resin-bonded fixed partial dentures. The models were scaled to ×2.5 to enhance visual analysis of the stress pattern. Results. Isochromatic fringes indicated a stress magnitude at the proximolingual areas of the pontic in the 3-unit resin-bonded fixed partial denture. In the 5-unit resin-bonded prosthesis, the stress pattern appeared to involve the entire surface of the pier retainer. Conclusion. The use of pier abutments should be avoided and it is more favorable to use 3-unit resin-bonded fixed partial dentures. (J Prosthet Dent 1998;80:661-5.)