In vitro fracture strength of endodontically treated premolars

The recent introduction of new bonding agents has led some authors to sugge st that certain endodontically treated posterior teeth could be restored wi th a bonded restoration instead of a full-coverage crown or onlay. To test the fracture resistance of endodontically treated premolars restored with a nd without bonding agents, we randomly divided 56 intact and caries-Free ma xillary premolars into seven groups as follows: unaltered teeth; access onl y; MOD prop and RCT; MOD prop, RCT, and amalgam restoration; MOD prop, RCT, and amalgam with 4-META bonding agent; MOD prep, RCT, and composite resin restoration; and MOD prep, RCT, and composite resin with 4-META bonding age nt, The teeth were subjected to compressive fracture tests in a Zwick 1435 Universal Testing Machine. Unaltered teeth and those with access only demon strated similar fracture strengths. Under the conditions of this study, the re was no significant difference in fracture strength between the experimen tal groups.