Assistant Professor, Restorative Dentistry Department, University at Buffalo School of Dental Medicine, Buffalo, NY.
Prosthodontics Resident, University at Buffalo School of Dental Medicine, Buffalo, NY.
J Prosthet Dent. 2024 Sep;132(3):645.e1-645.e7. doi: 10.1016/j.prosdent.2024.07.005. Epub 2024 Jul 15.
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.
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.
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).
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.
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.
尽管热循环对确定全口义齿的长期性能至关重要，但它对当代义齿基托材料的弯曲强度的影响仍未得到充分理解。
本体外研究的目的是评估不同 CAD-CAM 义齿基托材料的弯曲强度及其热循环的影响。
根据国际标准化组织（ISO）20795-1：2013 标准，从 6 种义齿基托材料中制作了 120 个矩形样本：一种热压 PMMA（[Lucitone 199 [C-L199]）、2 种铣削材料（Ivotion Base [M-IB]和 Lucitone Digital Fit [M-LDF]）和 3 种 3 维（3D）打印材料（Lucitone Digital Print [P-LDP]、Flexcera Base [P-FB]和 FotoDent Dentures [P-FD]）。将样本分为 2 组，每组 10 个；一半进行热循环，另一半不进行。热循环后的样本在 37°C 的蒸馏水中浸泡 2 天，然后在 5 和 55°C 下进行 5000 次热循环，停留时间为 30 秒。然后对它们进行三点弯曲强度测试。使用双向方差分析，然后进行事后 Tukey 多重比较检验，评估材料类型和热循环过程对义齿基托材料弯曲强度的影响（α=0.05）。
除了热循环后的 P-FB 之外，所有材料均符合 ISO 65MPa 弯曲强度标准。在未进行热循环的各种义齿基托材料（M-LDF>M-IB≈P-FD≈P-LDP>C-L199≈P-FB）和进行热循环的材料（M-LDF>M-IB≈P-FD>P-LDP≈C-L199>P-FB）之间，弯曲强度值存在显著差异（P<.05）。经过热循环后，测试材料的弯曲强度显著降低（P<.05）。
3D 打印义齿基托材料的弯曲强度值与铣削义齿基托材料相似或低于铣削义齿基托材料。热循环会影响义齿基托材料的弯曲强度。
