Influence of casting methods on marginal and internal discrepancies of complete cast crowns.
The relationship between the application of die-spacer prior to wax pattern fabrication and metal removal from the inner surface of the casting on marginal and internal discrepancies of complete cast crowns was evaluated. One hundred and twenty complete crowns were cast with palladium-silver alloy melted by gas-oxygen torch or electrical resistance and cast with a centrifuge casting machine. After casting, the crowns were seated on each type of different marginal configuration dies (90-degree shoulder, 20-degree beveled shoulder, and 45-degree chamfered shoulder) with a static load of 90 N during 1 min. Evaluation of the marginal fit of the specimens was made using a digital micrometer. The crowns were embedded in acrylic resin and longitudinally sectioned to verify the internal discrepancy that occurred in lateral and occlusal interfaces with a digital micrometer. The data were submitted to ANOVA and Tukey's test with a significance level of 5%. The best marginal and inner fits were obtained with the gas-oxygen torch source. The 45-degree chamfered shoulder showed the best marginal and inner fit, and better internal relief was obtained in the crowns abraded with 50 microm Al2O3 particles.
Milan
Fábio Machado
FM
Faculty of Dentistry of Piracicaba, University of Campinas, Piracicaba, SP, Brazil.
Consani
Simonides
S
Correr Sobrinho
Lourenço
L
Sinhoreti
Mario Alexandre Coelho
MA
Sousa-Neto
Manoel D
MD
Knowles
Jonathan C
JC
D000704:Analysis of Variance; D002484:Cementation; D003442:Crowns; D003722:Dental Alloys; D003735:Dental Casting Technique / Q000295:instrumentation; D018772:Dental Marginal Adaptation; D010165:Palladium; D012834:Silver; D018709:Statistics, Nonparametric; D019231:Tooth Preparation, Prosthodontic / Q000379:methods
D003722:Dental Alloys; D012834:Silver; D010165:Palladium