Comparison of marginal accuracy in two different materials used in provisional crown & bridge – An in vitro experimental study
Objectives: To determine the difference in the marginal accuracy at buccal, lingual, mesial and distal margins of temporary crowns fabricated with bisacryl based temporary crown material.
Methods: Two bisacryl based temporary crown material, Integrity and Protemp 4, were used to fabricate twelve temporary crowns each using the direct method. A pre-operative polyvinyl siloxane impression served as a template for temporary crown fabrication. A right mandibular molar tooth on a typodont was prepared to receive a crown. The provisional crown material was syringed onto the template and allowed to cure following the manufacturer’s instructions. All four surfaces of the crown were observed under a stereomicroscope equipped with digital SLR camera at 25.6x magnification. Once focused, the image of each surface was captured and a photographic record maintained. An image processing software was used for measurement of marginal discrepancy. Marginal accuracy between four surfaces was assessed using one-way ANOVA. To check for interaction between the material, surfaces and marginal discrepancy Factorial ANOVA was used. A p-value of <0.05 was considered significant.
Results: Mean marginal discrepancy for provisional crowns fabricated with Protemp 4 and Integrity was 410 ± 222 μm and 319 ± 176 μm respectively. The marginal discrepancy between the two groups was statistically significant (p = 0.027) with buccal margin exhibiting the most discrepancy (p < 0.01).
Conclusions: Integrity showed less microleakage than Protemp 4. Among all walls, buccal wall showed the most microleakage. Marginal accuracy is dependent upon the type provisional crown material and side of the prepared axial wall.