A clinical evaluation of cobalt-chromium metal-ceramic fixed partial dentures and crowns: A three- to seven-year retrospective study.
BACKGROUND
In severely compromised dentition, loading of long-span and cantilever metal-ceramic fixed partial dentures (FPDs) could result in framework deformation and porcelain fractures. The use of cobalt-chromium (Co-Cr) alloys may be advantageous, but there is little information on the longevity of, and complications with, prostheses made with these alloys.


OBJECTIVE
The aim of this retrospective study was to report the survival and complication rates of Co-Cr metal-ceramic FPDs and crowns followed over a 3- to 7-year period.


METHODS
The study included 42 patients with a total of 51 FPDs and 12 single crowns assigned to 1 of 3 groups. The 3 groups comprised patients with abutment teeth with a questionable prognosis (n=10), advanced chronic periodontitis (n=19), or abutment teeth with a positive prognosis (n=13). The FPDs had a mean of 9.7 units (range of 3-14). Of the FPDs, 32 were provided with a cantilever on 1 side (n=24) or both sides (n=8). The mean observation time was 51 months (range of 28-82). All patients were examined by 2 independent prosthodontists using the California Dental Association (CDA) assessment system for evaluation. One-way ANOVA with Fisher's LSD post hoc test and the Mann-Whitney U test were used for statistical analyses (alpha=.05).


RESULTS
Seventeen (34%) of the FPDs had biological and/or technical complications. Six (12%) FPDs were completely or partially removed during the observation period, 1 framework fractured, and 9 (17.6%) FPDs had ceramic fractures. Fifteen of the 21 fractured FPD units were related to FPDs that were placed in 3 patients with bruxing habits. The CDA rating for marginal integrity was "excellent" for more than 98% of the abutments. No patients reported adverse reactions to the material.


CONCLUSIONS
Metal-ceramic FPDs made of cobalt-chromium alloy performed acceptably in the questionable prognosis and advanced chronic periodontitis groups.
Eliasson
Alf
A
Department of Prosthetic Dentistry, Postgraduate Dental Education Center, Orebro, Sweden. alf.eliasson@orebroll.se
Arnelund
Carl-Fredrik
CF
Johansson
Anders
A
D002012:Bruxism / Q000150:complications; D002858:Chromium Alloys / Q000737:chemistry*; D002908:Chronic Disease; D003442:Crowns; D000044:Dental Abutments; D003722:Dental Alloys / Q000737:chemistry*; D003776:Dental Porcelain / Q000737:chemistry; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D003779:Denture Design; D003781:Denture Retention; D003830:Denture, Partial, Fixed; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D016876:Metal Ceramic Alloys / Q000737:chemistry*; D010518:Periodontitis / Q000150:complications; D012189:Retrospective Studies; D013499:Surface Properties; D016019:Survival Analysis
D002858:Chromium Alloys; D003722:Dental Alloys; D016876:Metal Ceramic Alloys; D003776:Dental Porcelain