TY - JOUR ID - 18421 TI - Evaluation and Comparison of the Vertical Marginal Discrepancy of Ni-Cr and Co-Cr Alloys Before and After Porcelain Firing: An in Vitro Study JO - Journal of Dental Materials and Techniques JA - JDMT LA - en SN - 2322-4150 AU - Kulkarni, Rahul S. AU - Jain, Deshraj AU - Prajapati, Aalap S. AU - Kulkarni, Poonam AD - Private Practitioner, Kulkarni Dental Clinic, Classic Centre Flat Number 101, Opposite Goyal Medical, Tilak Nagar Main Road, Indore -452001, Madhya Pradesh, India. AD - Professor, Head, & Dean, Department of Prosthodontics, Government Dental College & Hospital, Indore-452001, Madhya Pradesh, India. AD - Associate Professor, Department of Dentistry, Pramukh Swami Medical College, Bhaikaka University, Karamsad, Anand, Gujarat, India. AD - Ph.D Student at Gujarat University, Ahmedabad, Associate Professor in Department of Prosthodontics, Sri Aurobindo College of Dentistry, Indore, Madhya Pradesh, India Y1 - 2021 PY - 2021 VL - 10 IS - 3 SP - 148 EP - 156 KW - Base metal alloy copings KW - firing cycles KW - Marginal seal DO - 10.22038/jdmt.2021.55664.1428 N2 - Introduction: Marginal seal is the critical factor for the success of any restoration. Accuracy of marginal seal of copings depends on alloy systems & manufacturing techniques. In every technique like laser sintered, conventional casting etcetera, significant marginal discrepancy takes place after porcelain firing. The aim of this study is to evaluate and compare the vertical marginal discrepancy of Ni-Cr and Co-Cr alloys before and after porcelain firing. Methods: Custom made stainless steel die model was prepared to simulate the dimensions of the mandibular molar with a round shoulder margin. Cast copings of two base metal alloys Ni-Cr alloy & Co-Cr alloy were prepared. Total 40 copings were made and divided into two groups, G1 (Ni-Cr alloy) & G2 (Co-Cr alloy). According to alloy type, 20 specimens were used for each group of the study. The vertical discrepancy was measured with an optical LASER microscope (Nikon, Japan) before and after application of porcelain on the copings. Wilcoxon signed ranked test and Mann Whitney U test were used for Statistical analysis. Results: The median vertical marginal discrepancy before and after porcelain firing for Ni-Cr alloy was 48.13 and 52.87 um respectively and for Co-Cr alloy was 95.33 and 100.04 um respectively. There is a highly significant difference (P < 0.001) in the median vertical marginal discrepancy between Co-Cr alloy copings & Ni-Cr alloy copings before & after porcelain firing. Conclusions: Co-Cr alloy PFM restorations have double vertical marginal discrepancy compared to Ni-Cr alloy restorations but both the values can be considered within clinical acceptability range of the marginal discrepancy. UR - https://jdmt.mums.ac.ir/article_18421.html L1 - https://jdmt.mums.ac.ir/article_18421_3ebd86a55b160943329bf12df3b0acef.pdf ER -