Photoelastic analysis of stress patterns on teeth and bone with attachment retainers for removable partial dentures

This investigation was designed to evaluate the forces developed in supporting structures by removable partial dentures with attachment retainers. The attachments tested were the (1) Sterngold type 7, (2) Dalbo MK, and (3) Thompson dowel. The study utilized a photoelastic model with stress areas recorded photographically. The results showed that: 1. Splinted abutments are indicated when using the tested attachment retainers. 2. With single abutments, the attachment retainers induced distal force on the teeth which resulted in unfavorable horizontal bone forces. 3. The Dalbo MK attachments produced the most force on the edentulous regions and the least force on the abutment teeth. 4. The Thompson dowel and Sterngold type 7 attachment retainers induced similar stress patterns on single abutments and both produced distal abutment forces. 5. The Thompson dowel induced more favorable stress patterns when the abutments were splinted.