Quality of Ceramo-Metal Crowns produced in the Far East

Objectives: To reduce the costs in dental therapy German dentists often brief foreign labs to produce the dental prostheses required. The aim of this study was to compare the quality of single crowns produced by two different Far East dental labs by marginal gap measurement. Methods: The dental impressions of 50 randomly selected patients each were send to a lab in Thailand and a lab in China. All patients were provided with ceramo-metal crowns with non-precious alloy framework. The marginal discrepancy of one randomly selected crown of each patient seated onto the plaster die produced at the respective dental lab was determined by microscopic measurement at ten positions. The significance of the margin differences was determined by one-way ANOVA on the 0.05 level. Results: The size of the crown margins verified for the Thailand lab was 165.5 ± 72.1 µm. 12% of the crown means were even above 200 µm. The marginal gaps found for the crowns produced in the Chinese lab were significantly smaller (99.3 ± 25.7) (p=0.01). Conclusions: Big differences were found in quality of crowns produced in the Far East. Compared to literature the Chinese lab met the expected standard. However, the quality of the crowns of the second lab was not acceptable. Dentists briefing dental labs to produce dental prostheses should always make sure that the quality delivered is acceptable. Reduction of costs is not necessary equal to a lack of Quality.