Effect of Vertical versus Horizontal Preparation on Marginal Accuracy and Fracture Resistance of Monolithic Zirconia Crowns

Document Type : Original Article

Authors

1 lecturer of Prosthodontics , Faculty of dentistry , Menoufia University, Shebin Elkom , Egypt

2 Professor of Crowns and Bridges Faculty of Dental Medicine for Girls, Al-Azhar University, Cairo, Egypt

3 Lecturer of Fixed Prosthodontics Faculty of Dentistry , Faculty of Dentistry, Pharos University, Alexandria, Egypt

Abstract

Purpose: To assess effectiveness of vertical (featheredge) in comparison to horizontal (deep chamfer) preparation on marginal accuracy and resistance to fracture of monolithic zirconia crowns that have been thermomechanically aged. Materials and Methods: Ten epoxy resin dies were allocated into two equal groups based on the design of the finish line. Group (A): Horizontal prep (with 0.7 mm deep chamfer), and Group (B): Vertical prep (with 0.25 mm featheredge). The epoxy dies were fabricated by duplicating two stainless steel dies, one for each margin design. Then, these epoxy dies were scanned and designed for the milling of monolithic zirconia crowns with two finish line configurations. After being cemented to the epoxy dies, the crowns underwent thermocycling aging. Utilizing a digital microscope, the marginal gap distances were then measured. Following that, the fracture resistance test was conducted using a computer-controlled Universal Testing Machine with a load cell of 5 KN, and data was recorded using computer software. Data was collected and statistical analysis was carried out. Results: Featheredge preparation showed statistically insignificant lower marginal gap values than deep chamfer (P>0.05). A statistically significant superior fracture resistance was recorded for the deep chamfer group when compared to the featheredge group (pConclusions: Monolithic zirconia crowns with featheredge margins have similar marginal accuracy to those with deep chamfer. Although monolithic zirconia crowns with featheredge margins have lower fracture resistance values, the fracture load values remain within the accepted levels. Clinical Significance: Vertical preparation for monolithic zirconia crowns can be considered a viable conservative alternate to horizontal preparation.

Keywords

Al-Azhar Journal of Dentistry
Volume 11, Issue 2
April 2024
Pages 111-119

Files

Share

How to cite

Statistics