title: Endodontic access of all-ceramic crowns.
abstract: This study determines the effects of access opening on all-ceramic (Dicor) crowns. Forty-two extracted permanent teeth were selected to represent the various types of human teeth. Crown preparations were completed, polysulfide impressions made, and stone dies poured. The dies were forwarded to a commercial dental laboratory for fabrication of the restorations. The crowns were luted to the prepared teeth and endodontic access openings were completed by using established criteria for access preparation. The crowns were removed and examined by direct vision, transillumination, stereomicroscopy, and scanning electron microscopy. Two crowns fractured during access preparation, seven crowns exhibited craze lines, and 29 crowns exhibited chipping of the ceramic material adjacent to the access opening. There was no significant difference in the extent of chipping with diamond or carbide instrumentation. However, carbide instrumentation caused more fractures and craze lines than did diamond instrumentation.
authors.affiliation: Department of Restorative and Prosthetic Dentistry, University of Saskatoon, Canada.
authors.forename: J K
authors.initials: JK
authors.lastname: Sutherland
authors.forename: P E
authors.initials: PE
authors.lastname: Teplitsky
authors.forename: M B
authors.initials: MB
authors.lastname: Moulding
mesh_terms: D002516:Ceramics; D003442:Crowns; D003776:Dental Porcelain; D005898:Glass; D006801:Humans; D012390:Root Canal Therapy / Q000295:instrumentation / Q000379:methods
chemical_list: C047475:Dicor ceramic; D003776:Dental Porcelain