Comparison of Marginal Fit and Fracture Strength of a CAD/CAM Zirconia Crown with Two Preparation Designs

  • Hamid Jalali Faculty of Dentistry, Tehran University of Medical Sciences
  • Leyla Sadighpour Associate professor, Prosthodontics department, School of Dentistry, Tehran University of Medical Sciences
  • Ali Miri Faculty of Dentistry, Tehran University of Medical Sciences
  • Ahmad Reza Shamshiri Faculty of Dentistry, Tehran University of Medical Sciences
Keywords: Zirconium Oxide, Computer-Aided Design, Prosthesis Failure, Dental Marginal Adaptation

Abstract

Objectives: The purpose of this in vitro study was to compare the marginal adaptation and fracture resistance of a zirconia-based all-ceramic restoration with two preparation designs.

Materials and Methods: Twenty-four mandibular premolars were randomly divided into two groups (n=12); the conventional group received a peripheral shoulder preparation and the modified group received a buccal shoulder and proximal/lingual chamfer preparation. The marginal fit of the zirconia crowns (Cercon) was evaluated using a stereomicroscope. After cementation, load was applied to the crowns. The mean fracture load and the mean marginal gap for each group were analyzed using t-test (P=0.05).

Results: The mean marginal gap was 71±16µm in the conventional group and 80±10µm in the modified group, with no significant difference (P=0.161). The mean fracture strength was 830±153N for the conventional group and 775±125N for the modified group, with no significant difference (P=0.396). All but one fracture occurred in the veneering ceramic.

Conclusion: Less aggressive preparation of proximal and lingual finish lines for the preservation of tooth structure in all-ceramic restorations does not adversely affect the marginal adaptation or fracture strength of the final restoration.

Author Biographies

Hamid Jalali, Faculty of Dentistry, Tehran University of Medical Sciences
assitant Professor, Prosthodontics Department
Leyla Sadighpour, Associate professor, Prosthodontics department, School of Dentistry, Tehran University of Medical Sciences
Associate professor, Prosthodontics Department
Ali Miri, Faculty of Dentistry, Tehran University of Medical Sciences
Prosthodontist
Ahmad Reza Shamshiri, Faculty of Dentistry, Tehran University of Medical Sciences
Dentistry Research Institute, Department of Community Oral Health
Published
2016-08-15
How to Cite
1.
Jalali H, Sadighpour L, Miri A, Shamshiri A. Comparison of Marginal Fit and Fracture Strength of a CAD/CAM Zirconia Crown with Two Preparation Designs. Front Dent. 12(12):874-881.
Section
Original Article