Retention Of Selected Cores To All-ceramic Posts And Fracture Resistance Of The All-ceramic Posts In Post-and-core System

Conventional cast metal post-and-core may shine through all-ceramic crowns and thin gingival tissue. When nonprecious alloys are used, corrosion products may lead to discoloration of gingival tissue and the root. All-ceramic post-and-core can be used to prevent these problems. The focus of recent studies of all-ceramic post-and-core is the two-piece technique, which involves a prefabricated zirconia ceramic post. Primarily, a reliable retention of the core to the post must be achieved. Secondarily, the strength of the post can not be influenced during the combination of the core with the post.This study uses alumina-zirconia nano-composite infiltrated ceramics to fabricate two-piece post-and-core, and compares the retention of selected cores to all-ceramic posts and the fracture resistance of the all-ceramic posts in post-and-core restoration. The results of tests indicate as following:1. A reliable retention of the core to the post can be achieved when the alumina-zirconia nano-composite infiltrated ceramic core is formed and combined with the post by direct sintering, which offers significantly higher retention than adhensiving. Direct sintering also shows significantly higher retention than forming composite resin core onto the post.( P<0.01)2. The strength of the post dose not be influenced during the combination of the core with the post by direct sintering. (P>0.05)3. Combining the alumina-zirconia nano-composite infiltrated ceramic core with the post by direct sintering can be expected a prosperous clinical application in the future.