A comparitive evaluation of the marginal adaptation of zirconium coping and nickel-chromium coping using shoulder finish line design: an invitro study.

Marginal adaptation is an important factor for long term clinical success of the restoration. This study aims to evaluate and compare the marginal adaptation of zirconium coping and nickel-chromium coping using the shoulder finish line design. For the purpose of this study 30 master dies were fabricated. A total of 30 copings were fabricated in which 15 zirconia copings and 15 Ni-Cr copings were fabricated. The copings obtained were seated on the die and marginal discrepancy between the metal die and the copings were then measured with Scanning electron microscope at magnification of ×50 and the findings were statistically analyzed. Mean and standard deviation values of marginal discrepancy of cervical margins of zirconia copings were 39.32 and 2.66 μm and Ni-Cr copings were 129.98 and 2.57 μm. Higher mean marginal gap (μm) is recorded in Ni-Cr copings compared to zirconia copings. The difference in mean marginal gap (μm) between the two copings is found to be statistically significant (P < 0.001). Within the limitation of this study it was concluded that higher mean marginal gap (μm) was recorded in Ni-Cr copings compared to zirconia copings. The difference in mean marginal gap (μm) between the two copings is found to be statistically significant (P < 0.001).