Abstract
Purpose: Endodontically treated teeth have generally been rebuilt with a dowel and cores, and then they are restored with full coverage restorations. However, longitudinal outcomes of those restorationsdo not always demonstrate good results, often exhibiting clinical complications, such as dislodgementand root fracture. This study investigated the possibility of partial coverage restorations forendodontically treated posterior teeth.
Methods: One hundred forty extracted human premolars, which had been selected under certaincriteria, were divided into 14 groups, with 10 teeth each. MOD cavities were prepared with a narrowisthmus, and with a wide isthmus, and then restored by the following methods: Group 1 consisted ofintact teeth; in Groups 2-4 and 10, cavities were prepared without restorations; Groups 5, 6, and 11were restored with light-cured composite resin fillings; Groups 7, 8, and 12 received cast inlay restorations;Groups 9, 13, and 14 received cast onlay restorations. Thereafter, the specimens underwent aloading test, and their fracture loads and modes were recorded and compared.
Results: Among all cavities and restorations, cast onlay restorations luted with adhesive resin cementshowed the highest fracture load, but sustained unrestorable fractures. Cast inlay restorations werenext, while composite resin fillings showed a significantly lower fracture load, but sustained restorablefractures.
Conclusion: Endodontically treated posterior teeth could be safely restored with partial coveragerestorations of cast onlays, because they were stronger than intact teeth. In addition, bonding agentsfor composite resin fillings and adhesive resin cements for cast restorations were significantly effective.
