Design Matters

How Occlusal Surface Geometry Influences the Fracture Resistance of CAD/CAM Restorations

Autores

  • Rafal Kareem Rasheed
  • Qusay Abdulateef Hasan
  • Evan Hussain Alwan
  • Zeina Talib Kareem
  • Safa Abdalrahman Hussain , Al-Rashid University College/Department of Dentistry

DOI:

https://doi.org/10.5195/d3000.2026.1456

Palavras-chave:

Fracture, Zirconia, Anatomy, CAD/CAM

Resumo

This study evaluated the effect of occlusal surface design (anatomic vs. non-anatomic) on the fracture resistance of monolithic zirconia full crowns fabricated using CAD/CAM technology. A mandibular first molar was prepared with 1.5 mm occlusal and 1.0 mm axial reduction (90° shoulder finish line) to serve as a master die. The die was duplicated using a heavy-body silicone index to produce 40 type IV stone dies, randomly divided into two groups (n=20): Group A (full anatomic occlusal design) and Group B (modified non-anatomic/flat occlusal design). Crowns were milled via CAD/CAM, sintered, and seated on their respective dies. Axial loading was applied using a rounded indenter in a Universal Testing Machine at a crosshead speed of 1 mm/min) until fracture, and the maximum load (N) was recorded. Group A exhibited a mean fracture resistance of 2063 N (range 1903-2173 N). Group B demonstrated a highly comparable mean fracture resistance of 2059 N (range 1987-2125 N). Statistical analysis showed no significant difference between the two groups (p = 0.905). Modifying the occlusal design from anatomic to flat does not significantly affect the fracture resistance of monolithic zirconia crowns. Both designs demonstrated exceptional load-bearing capacities that comfortably exceeded maximum clinical masticatory forces.

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Publicado

2026-07-23

Edição

v. 14 n. 2 (2026)

Seção

Infancy & Adolescence

Licença

Copyright (c) 2026 Rafal Kareem Rasheed, Qusay Abdulateef Hasan, Evan Hussain Alwan, Zeina Talib Kareem, Safa Abdalrahman Hussain

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