Evaluation of fit of metal coping fabricated with stereolithography

Abstract

Objectives The purpose of this study was to evaluate the clinical acceptability of the marginal and internal gap of Co-Cr metal copings fabricated with stereolithography(SLA)Materials and MethodsA resin tooth of a maxillary right first premolar was prepared for metal ceramic crown with a deep chamfer margin. Titanium master dies were milled after scanning of the prepared tooth (n=45). For group I, Co-Cr metal copings were made from conventional lost-wax technique (LW, n=15). For group II, the master dies were scanned and designed with CAD system. Then, metal copings were milled with Co-Cr (MC, n=15). For group III (SL, n=15) , the scanning and design procedures were same as group II and burn-out resins were fabricated with SLA device. Then, Co-Cr alloy was used for casting and finising. The marginal and internal discrepancies were measured under an optical microscope(100x) on eleven reference points and were statistically analyzed with one-way ANOVA (α=.05).ResultsThe mean total discrepancies was 63.24 µm (SD:16.58) in the LW group and 70.18 µm (SD:15.52) in the SL group. The MC group showed the largest total mean value (130.33µm/SD:13.77). There was statistically significant difference between the MC and the other groups. (p<0.05) The mean marginal gap of the SL group was the smallest among 3 groups (Mean:51.57 µm/SD:17.74) and there was no statistically significant difference between the LW and SL group. The axial gap showed similar to marginal gap. The LW group presented the smallest value in terms of occlusal gap and the MC group was the largest. There were statistically significant differences among all three groups in occlusal measurement. ConclusionCo-Cr metal copings fabricated with SLA technology showed clinically acceptable value on marginal and internal gap and there was no statistically significant difference between conventional lost-wax technique and SLA.