Format

Send to

Choose Destination
See comment in PubMed Commons below
J Dent Res. 1994 Dec;73(12):1824-32.

Fracture surface characterization of clinically failed all-ceramic crowns.

Author information

1
Department of Dental Biomaterials, College of Dentistry, University of Florida, Gainesville 32610-0446.

Abstract

The goal of this study was to establish a protocol for the retrieval and fractographic analysis of failed restorations, and to compare the fracture surface features of clinically failed ceramic restorations and with those of controlled laboratory test specimens fabricated from the same materials. Ten fractured Dicor crowns and 12 fractured Cerestore crows were retrieved and analyzed. Optical microscopy of the failed crowns revealed that the critical segments of nine of the 10 (90%) Dicor crowns and nine of the 12 (75%) Cerestore crowns were acceptable for fractographic analysis. Twelve disks of each material were fabricated as controls and fractured by bi-axial flexure for analysis of the similarities and/or differences between the fractographic features of fractured clinical crowns and the disks. Each of the 10 Dicor crowns was observed to fail along the internal surface. For 78% of the Cerestore crowns, failure initiation occurred at the porcelain/core interface or inside the core material. Critical flaw sizes of the failed Dicor crowns ranged from 127 to 272 microns. Failure stresses of the Dicor crowns, estimated by fractographic techniques and fracture mechanics relationships, ranged from 65 to 94 MPa. Estimated failure stresses for two of the Cerestore crowns which had failure initiation sites in the porcelain layer were 15 and 68 MPa. It is concluded that the fracture initiation sites of dental ceramics are controlled primarily by the location and size of the critical flaw, and not by specimen thickness.

PMID:
7814754
DOI:
10.1177/00220345940730120601
[Indexed for MEDLINE]
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Atypon
    Loading ...
    Support Center