Comparison of the marginal fit of Procera AllCeram crowns with two finish lines

Purpose: The purpose of this study was to determine the influence of two finish line configurations on the marginal accuracy of Procera AllCeram crowns. Materials and Methods: Twenty mechanized specimens of brass were fabricated for complete-coverage crowns. Two finish line designs were used: chamfer and rounded shoulder. AllCeram crowns were fabricated, and the fit of the crowns to the dies was recorded from the buccal and lingual margins. An image-analysis program was used to measure the gap. The results were subjected to statistical analysis using a Student's t test for separate samples and Student's paired t test. Results: No significant differences were observed between the buccal and lingual measurements. When the values of the buccal and lingual measurements were averaged, there were no significant differences in the marginal gap, horizontal discrepancy, or internal adaptation of the axial wall, but there were significant differences in the vertical discrepancy, absolute marginal discrepancy, and internal discrepancy between the two finish line designs. Conclusion: The marginal gap was within the range of clinical acceptability. Some of the variables were influenced by the two finish lines tested.