Evaluation of internal and marginal fit of two metal ceramic system - in vitro study.

INTRODUCTION

The high strength porcelain fused metal crowns have been extensively used in dentistry. However, the fit is the most encountered problems in porcelain fused metal crowns. This mainly depends on the fabrication technique.

AIM

The purpose was to compare the internal and marginal fit of laser sintered and conventionally casted Cobalt-Chromium copings.

MATERIALS AND METHODS

Twenty stainless steel dies of dimension 15 x 10 mm with 1 mm finish margin were fabricated using CAD-CAM technology. Twenty dies were divided into two groups Group 1 and Group 2 containing 10 samples each. All 20 dies were scanned using LAVA 3M scanner and data were used to fabricate metal copings using Laser sintering technique (Group-1) and Conventional casting technique (Group-2). Copings were cemented onto respective dies and finished and standardized sectioning were made. The sectioned models were scanned under stereomicroscope at 50 x magnification for internal and marginal fit evaluation.

RESULTS

Mean and standard deviation of internal and marginal discrepancy of laser sintered copings/conventional cast metal copings was 107.6 ± 10.9μ and 102.1 ± 17.2μ/187.09 ± 11.47 μ and 176.57 ± 25.82 μ respectively. Statistical analysis showed the laser sintered copings have lesser internal and marginal discrepancy than conventional casted copings with p value < 0.001.

CONCLUSION

The laser sintered Co-Cr copings showed better internal and marginal fit when compared to that of conventional Co-Cr casted copings.