A study on post length for fiber post and composite resin core restorations

Abstract

PURPOSE: This in vitro study investigated the use of short posts for fiber post and composite resin core restorations. METHODS: A replica of a human maxillary central incisor was prepared from bovine teeth using the CELAY system (MIKRONA, Switzerland). Specimens consisted of three different post lengths (2, 5, 8 mm) and three types of remaining coronal tooth structure (0, 0.5, 1 mm). The failure load and failure mode in the fiber post and composite resin core and cast metal post and core restorations were compared. RESULTS: There was no significant difference in failure load between both post and core methods with 1 mm of remaining coronal tooth structure. Therefore, shorter posts may be used in this condition. High failure loads were recorded with 5 and 8 mm post lengths that had 0 mm of remaining coronal tooth structure in cast metal post and core restorations. However, there was no significant difference in failure load with any post length in fiber post and composite resin core restoration. A high failure load was recorded with 5 mm and 8 mm post lengths that had 0.5 mm of remaining coronal tooth structure. A long post may be required in cases with less coronal tooth structure. The failure mode was repairable for fiber posts with 0 mm of remaining coronal tooth structure. However, the failure mode was impossible to repair in those that had 0.5 mm, 1 mm of remaining coronal tooth structure. CONCLUSION: This in vitro study suggested that short post lengths would be adequate for fiber post and composite resin core restorations. However, the failure mode may be impossible to repair when using a fiber post.