Mechanical Behavior of CSC Telescope Crowns

Abstract

The mechanical behavior of crown and sleeve-coping (CSC) telescope crowns was compared with that of cone (Konus) telescope crowns under various loading conditions using the finite element method. Three configurations were evaluated :
1. Frontal and sagittal models of single unit crowns on the maxillary and mandibular left second premolars.
2. A unilateral free end RPD (mandibular left first and second abutment prepared premolar teeth and mandibular left first and second molar teeth).
3. A bilateral splint with palatal connector between the maxillary second premolars. The following results were obtained :
1. As the load angle increased in the single unit crown models, deflections of the outer crown and the abutment tooth increased, and stresses concentrated on the surface of the inner crown.
2. Stresses induced in the apical region of the periodontal membrane of the distal abutment teeth were greater with the CSC than the Konus. In the CSC, vertical deflections at the apex of the abutment teeth were greater than horizontal deflections.
3. Stresses induced in the periodontal membrane and alveolar bone were less with the CSC than with the Konus. However stresses at the joint region of the palatal bar and outer crown were greater with the CSC than the Konus.
The CSC was found to be an effective prosthodontic treatment when viewed in terms of deflections and stresses induced in the abutment teeth, periodontal membrane and alveolar bone.