Comparison of posterior indirect adhesive restorations (PIAR) with different preparation designs according to the adhesthetics classification. Part 1: Effects on the fracture resistance.

Aim: To investigate whether: 1) in the adhesive era, a full-crown restoration in a molar tooth is more resistant compared with an overlay-type restoration; b) a posterior indirect adhesive restoration (PIAR) is similar to a sound tooth from a mechanical point of view.

Materials And Methods: Seventy extracted molars were divided into five groups (1. Butt Joint; 2.