Effect of thermal cycling on the flexure strength of CAD-CAM denture base materials: An in vitro study.

Statement of Problem: The impact of thermal cycling on the flexure strength of contemporary denture base materials remains inadequately understood despite its crucial role in determining the long-term performance of complete dentures.
Purpose: The purpose of this in vitro study was to evaluate the flexural strength of different CAD-CAM denture base materials and the effects of thermal cycling.
Material and Methods: A total of 120 rectangular specimens were fabricated from 6 denture base materials according to the International Organization for Standardization (ISO) 20795-1:2013 standard: a heat-compressed PMMA ([Lucitone 199 [C-L199]), 2 brands of milled material (Ivotion Base [M-IB] and Lucitone Digital Fit [M-LDF]), and 3 types of 3- dimensionally (3D) printed material (Lucitone Digital Print [P-LDP], Flexcera Base [P-FB], and FotoDent Dentures [P-FD]). Specimens were divided into 2 subgroups of 10; half underwent thermocycling, half did not. Thermally cycled specimens were immersed in distilled water at 37 °C for 2 days, followed by 5000 thermal cycles at 5 and 55 ºC, with a dwell time of 30 seconds. They were then subjected to a 3-point flexural strength test. Two-way ANOVA, followed by post hoc Tukey multiple comparison tests were used to assess the effect of material type and the thermal cycling process on the flexural strength of denture base materials (α=.05).
Results: All materials met the ISO standard of 65 MPa flexural strength, except for thermal cycled P-FB. A significant difference (P<.05) in flexure strength value was found among various denture base materials without thermal cycling (M-LDF>M-IB≈P-FD≈P-LDP>C-L199≈ P-FB) and with thermal cycling (M-LDF> M-IB≈P-FD>P-LDP≈C-L199>P-FB). The flexural strength of tested materials was reduced significantly (P<.05) with thermal cycling.
Conclusions: Three-dimensionally printed denture base materials have a flexural strength value similar to or less than that of milled denture base materials. Thermal cycling impacts the flexural strength of denture base materials.
(Copyright © 2024 Editorial Council for The Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)