Influence of Deep Marginal Elevation on Fracture Resistance of Endocrown Restorations Constructed from Two Cad/Cam Blocks (An In-Vitro Study)

Document Type : Original Article

Authors

1 fixed prosthodontic ELnahda university

2 Professor Oral and Maxillofacial Radiology Faculty of Dentistry Minia Univeristy

3 Associate Professor of Fixed Prosthodontics, Faculty of Dentistry, Minia University, Minia, Egypt.

10.21608/edj.2025.395843.3515

Abstract

ABSTRACT
1. Objective: To assess the impact of fracture resistance on the marginal adaptation of endodontically treated teeth restored with endocrowns fabricated from two CAD/CAM ceramics in an in vitro model.
2. Materials and Methods: Forty sound mandibular first molars underwent endodontic treatment and were prepared for endocrowns with a butt-joint occlusal edge and a mesial proximal box. The participants were categorized into two groups (n=20 each) according to ceramic type: Group H (hybrid ceramic) and Group L (LDS ceramic). Each group was further partitioned into subgroups E (exhibiting marginal elevation) and N (lacking marginal elevation), with 10 specimens each. The endocrowns were affixed with dual-cured self-adhesive resin cement and subjected to 5000 thermal aging cycles ranging from 5°C to 55°C. All specimens were thereafter submitted to a fracture resistance test using a universal testing equipment. The gathered data was documented, organized, and submitted for statistical analysis.
3. Results: The LDS ceramic subgroup with deep marginal elevation (LE) exhibited considerably greater fracture resistance compared to all other evaluated subgroups (P < 0.001).
4. Conclusion: In comparison to LDS IPS E.max, hybrid ceramics, both with and without marginal elevation, demonstrate enhanced fracture resistance.

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Egyptian Dental Journal
Volume 71, Issue 4 - Serial Number 4
Fixed Prosthodontics, Removable Prosthodontics and Dental Materials
October 2025
Pages 3177-3189

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