Comparative Microscopic and Radiographic Evaluation of Proximal Marginal Integrity of CAD/CAM PMMA Crown and CAD/CAM Zirconia Monolithic Crown- An In-vitro Study

ABSTRACTS Aim: to evaluate and compare proximal marginal integrity radiographically and microscopically of CAD/CAM PMMA crown and CAD/CAM monolithic zirconia crown. Materials and methods: Fifteen maxillary or mandibular molar teeth with standardized anatomic preparation for provisional crown and monolithic zirconia crown were scanned with a 3-dimensional laboratory scanner. CAD/CAM crowns were designed 3-dimensionally using exocad software and then milled from presintered blocks in a milling machine. The proximal marginal integrity of CAD/CAM PMMA and monolithic zirconia crown were evaluated radiographically and microscopically. For radiographic evaluation, radiopaque dye is used to measured proximal marginal discrepancies on six reference points on PMMA crown. A digital microscope was used to measure the marginal discrepancies on six reference points on PMMA and zirconia crown. Photographs of the proximal marginal areas were captured at six reference lines at standardized orientation and placement of the samples. In all photographs margin was traced with the help of HiViewSetup software. The mean marginal discrepancies for each group were analysed using chi-square test and man whitney U test. Results: the test result shows there were no significant differences in radiographic and microscopic evaluation of CAD/CAM PMMA crown and CAD/CAM monolithic zirconia crown. Conclusion: It is found that radiographically, PMMA crown had greater marginal discrepancy as compared to the Zirconia crown. Microscopically, PMMA crown and the CAD/CAM monolithic zirconia crown had almost similar marginal discrepancy (statistically non- significant).