Influence Of Attachment Systems In Mandibular Class I Hybrid Dentures

Objectives: The aim of this study was to evaluate the influence of different attachment systems in mandibular class I hybrid dentures. A study through photoelasticity. Methods: Four different planning of free-end removable partial dentures with different attachment systems were determined: (1) clasp; (2) ASC-52 system (CNG Soluções Protéticas, São Paulo, Brazil); (3) ERA system (Sterngold, Attleboro, MA, USA); and (4) semi-precision attachment PD-Score (CNG Soluções Protéticas, São Paulo, Brazil). The models were fabricated with photoelastic resin PL-2 (Vishay, Micro-Measurements Group, Inc Raleigh, N.C. USA). Axial loads of 100N were applied to each tooth of the removable partial denture by a universal testing machine (EMIC-DL 3000) and a circular polariscope was used to visualize the stress. The results were photographed and analyzed qualitatively using a graphic software (AdobePhotoshop). Results: The denture with semi-precision attachments generated the greatest stress in the apex, between the roots of the distal abutment teeth and in the distal region of the residual ridge. The denture with resilient attachments exhibited the greatest stress concentration in the distal cervical region of the distal abutment teeth. Conclusions: The denture with clasp presented the best stress distribution. The denture with the semi-precision attachment PD-Score was less favorable for stress transmission. The dentures with the ASC-52 and ERA systems exhibited similar and intermediate performance.