Authors : Dr. Divya Bhartiya; Dr. Deshraj Jain; Dr. Alka Gupta; Dr. Mukesh Soni; Dr. Suthakar P

Volume/Issue : Volume 8 - 2023, Issue 7 - July

Google Scholar : https://bit.ly/3TmGbDi

Scribd : https://tinyurl.com/v2usj65k

DOI : https://doi.org/10.5281/zenodo.8185947

Abstract : Background: The success of crown restorations relies on several crucial factors, including achieving pleasing esthetics, ensuring excellent resistance to fractures, and achieving a flawless marginal fit. When the luting agent dissolves and microleakage occurs, it is often linked to an escalation in marginal crown discrepancies. Insufficient marginal adaptation can result in secondary caries and have a negative impact on periodontal health by promoting greater plaque retention and causing alterations in the subgingival microflora. Marginal and internal adaptations were reported to be different depending on the type and material of indirect restorations. Purpose: To evaluate and compare the marginal fit and internal adaptation of PFM, Zirconia and GCAM crowns fabricated using CAD-CAM. Materials and methods: An experimental, comparative in-vivo study was conducted among 45 patients of age group 20-50 years each having a single molar crown replacement, and were randomly divided into three groups: Group I- G-CAM crowns, Group II – Zirconia crowns and Group II- PFM crowns. Ideal tooth preparations were performed and before cementation of the final prosthesis marginal fit was measured using the silicone replica method. The silicone replicas were extracted from the respective crowns with care, and then they were sectioned into four parts per specimen, both buccolingually and mesiodistally, using a razor blade. To assess their thickness, four measurements were taken at the marginal region and four measurements at the occlusal region of each replica. A stereomicroscope was employed for precise measurements in this process. The marginal fit and internal adaptation were assessed based on the thickness of the sections. The intergroup comparison for the difference of mean scores between independent groups was done using the One Way ANOVA and independent t test.The distribution of the data was assessed using the Shapiro-Wilk test, while the homogeneity of the variables was examined through Levene's test. The data was found to be homogeneous and normally distributed. For each variable, the mean and standard deviation (SD) were calculated. Results: The mean Marginal Discrepancy in the Group I was 107.942μms, in Group II was 107.682μms, in the Group III was 117.312μms. The mean occlusal gap in the Group I was 210.842μms, in Group II was 259.762μms, in Group III was 154.862μms. The intergroup comparison between the three groups was statistically significant when analyzed using One way ANOVA at p value of 0.001. Conclusion: Within the constraints of the study, all three groups of G-CAM, Zirconia, and PFM crowns exhibited marginal discrepancies and internal discrepancy values within an acceptable range. The occlusal regions demonstrated the highest values, while the marginal regions displayed the lowest values. Also the properties of newer metal free CAD-CAM materials need to be further studied to evaluate their use for long term esthetic restorations.

Keywords : Marginal fit, G-CAM, CAD-CAM, Internal adaptation, Stereomicroscope, silicone replica.