All ETDs from UAB

Advisory Committee Chair

Nathaniel Lawson

Document Type

Thesis

Date of Award

2024

Degree Name by School

Master of Science in Dentistry (MScD) School of Dentistry

Abstract

Purpose: The purpose of this study is to compare the wear characteristics and fatigue resistance of two dental crown materials: SprintRay Ceramic Crown, a 3D-printed resin material, and IPS™ e.Max CAD, a lithium disilicate material. Methods: This study evaluates wear and fatigue characteristics of dental crowns made from Ceramic Crown (SprintRay) and IPS e.max CAD LT (Ivoclar). For fatigue testing, custom fatigue devices were utilized to subject the crowns to cyclic loading, simulating occlusal forces. The specimens underwent 100,000 cycle intervals until 1.5 million cycles at a load of 40N of fatigue loading, with inspections conducted for signs of debonding, fracture, or other failures. The fatigue resistance of each material was evaluated based on the number of cycles endured before failure occurred. In the wear testing phase, custom wear devices were employed to simulate masticatory forces and assess material wear. Samples were subjected to 400,000 cycles of sliding against enamel antagonists under a 15 N load. Surface wear was evaluated using non-contact profilometry, and wear mechanisms were elucidated through scanning electron microscopy analysis of worn surfaces. Signs of abrasive or fatigue wear were identified, providing insights into the materials' wear resistance and durability. Results: The study compared volume loss between IPS Emax CAD and Sprintray Ceramic Crown materials on flat and enamel surfaces across incremental cycles (100k to 400k). Notably, at 100k cycles, Sprintray exhibited a mean volume loss of 0.0441 mm3 on flat surfaces, whereas Emax showed 0.2080 mm3. This trend continued, with Emax consistently demonstrating higher volume loss than Sprintray across all cycle increments. At 400k cycles, the mean volume loss for Sprintray Ceramic Crown on flat surfaces was 0.0705 mm³, significantly lower than IPS Emax CAD at 0.4610 mm³ (p < 0.001). Similarly, on enamel surfaces, Sprintray exhibited a mean volume loss of 0.9470 mm³, notably less than IPS Emax CAD with 1.8070 mm³ (p < 0.001). Both materials showed 100% survival after 1.5 million cycles in the crown fatigue test, indicating resilience under stress. Conclusion: The study confirms that 3D-printed resin crowns and lithium disilicate crowns exhibit similar durability under cyclic loading, supporting our initial hypothesis. However, contrary to our expectations, significant differences were observed in volumetric wear and opposing enamel wear between the two materials. IPS E.max CAD showed higher wear rates and greater impact on opposing enamel surfaces compared to SprintRay Ceramic Crown.

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Dentistry Commons

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