Resistance of premolars restored on different types of partial preparations

Objectives: The purpose of this study was to evaluate the resistance to the axial compression of premolar teeth recuperated with ceramic on different types of partial dental preparations. Methods: On the oclusal of premolars, a test of axial compression was accomplished with a sphere of 9mm Ø on the different formed groups: With this purpose, being used the ceramic Vitadur Alpha (Vita Zahnfabrik), it was executed the following preparations (14 specimens for group): I. restorations MOD of the type Inlay; II. Restorations of the type MOD with covering of the functional cusp - Onlay; III. Restorations of the type MOD with covering both cusps – Overlay. These groups were compared with intact and young premolar human extracted teeth (group IV - it controls). For the foundation of the ceramic, half of the specimens of each group was cemented with the Enforce resin cement (Dentisply) and the other half with the Relyx resin cement (3M) that were manipulated according to the manufacturers' recommendations. Results: the variance analysis appeared for a significant difference among the cements (p <0,881) and dental preparations (p <0,0001). Conclusions: The Relyx resin cement made possible a larger resistance to the fracture to the premolars than made possible with the cement Enforce. The restorations of the type Inlay presented the largest resistance values and they were similar to the intact teeth - control. The restorations Onlays and Overlays didn't differ to each other but they presented the smallest fracture resistance being inferior to the Inlays restorations and group controls. (Support FAPERGS)