Clinical performance of two different CAD/CAM-fabricated ceramic crowns: 2-Year results.
BACKGROUND
Recently, technical problems, especially chipping, have been reported for ceramic restorations; as a result, ceramic crowns produced entirely by computer-aided design and computer-aided manufacture (CAD/CAM) have become popular because the incidence of chipping is less.


OBJECTIVE
The purpose of this study was to report on 2-year results for 2 different types of CAD/CAM ceramic crowns placed in adult patients in a dental practice.


METHODS
Sixty participants who required a crown for a first or second molar were randomly assigned to 1 of 2 groups. Crowns in the veneered zirconia (VZ) group were made of zirconia frameworks veneered with CAD/CAM-produced lithium disilicate ceramic; the other group's crowns were made of monolithic lithium disilicate (MLD) ceramic. Each crown was reviewed after 2 weeks, 1 year, and 2 years by using modified the US Public Health Service (USPHS) criteria. Statistical analysis was performed by using the log-rank test, nonparametric tests, and Kaplan-Meier survival analysis.


RESULTS
All 60 participants were recalled after 1 and 2 years. In the VZ group, 2 endodontic complications occurred, and deterioration of periodontal health was observed for 3 participants. In the MLD group, 2 endodontic complications occurred within 2 years. In both of the groups, no caries or marginal discoloration was observed. No technical complications, for example, cracks, chipping, or fractures, were detected after 2 years. The shape and appearance of all crowns were assessed positively by the examining dentist. The log-rank test showed no significant differences in respect to technical or biologic complications (P=.324).


CONCLUSIONS
For both types of single-crown restoration, no technical failures occurred. The number of biological complications did not differ significantly between the types of crowns.
Private practice, Bad Schoenborn, Germany. Electronic address: seydler@dr-seydler.de.
Bodo
B
Seydler
Associate Professor, Department of Prosthodontics, University of Heidelberg, Heidelberg, Germany.
Marc
M
Schmitter
D000328:Adult; D001294:Attitude to Health; D002484:Cementation / Q000379:methods; D003116:Color; D017076:Computer-Aided Design; D003442:Crowns; D045662:Dental Etching / Q000379:methods; D003764:Dental Materials / Q000737:chemistry*; D003776:Dental Porcelain / Q000737:chemistry; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D003801:Dental Veneers; D004955:Esthetics, Dental; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D019279:Resin Cements / Q000737:chemistry; D012821:Silanes / Q000737:chemistry; D013499:Surface Properties; D019553:Tooth, Nonvital / Q000628:therapy; D016896:Treatment Outcome; D015040:Zirconium / Q000737:chemistry
D003764:Dental Materials; C520133:IPS e.max CAD LT; D019279:Resin Cements; D012821:Silanes; C493120:lithia disilicate; C502351:multilink adhesive system; D003776:Dental Porcelain; D015040:Zirconium; C028541:zirconium oxide