Lyu Huaxin, Murakami Natsuko, Yamazaki Toshiki, Wada Junichiro, Utsumi Miona, Wakabayashi Noriyuki
Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
J Prosthodont Res. 2023 Apr 12;67(2):196-205. doi: 10.2186/jpr.JPR_D_22_00011. Epub 2022 May 27.
Purpose We aimed to assess removable partial denture occlusal rests composed of polyether-ether-ketone (PEEK) and zirconia, using finite element analysis.Methods Three-dimensional PEEK and zirconia rest models, including the occlusal rest (1.5 mm thickness at the basal portion, 3.0 mm width) and minor connector (1.5 mm thickness, 6.0 mm height), and rest seat models with mechanical properties of enamel were constructed. The radius of transitional curvature between the rest and minor connector was 0.1-0.5 mm. The rest and rest seat model interfaces were set as frictional contacts (μ = 0.1), and the base of the rest seat model was restrained in all the directions. A 100 N downward load was applied perpendicular to the bottom surface of the minor connector. The maximum value of the first principal stress (Max-S1) was compared to the flexural and fatigue strengths of each material. Occlusal rests with 1.0-2.0 mm thickness, 2.0-3.5 mm width, and 0.5 mm radius of transitional curvature were analyzed.Results Max-S1 was observed at the transitional part and decreased with increasing radius of the transitional curvature, rest width, and thickness. PEEK rests with at least 1.5 mm thicknesses and 3.0 mm widths showed lower Max-S1 than the flexural strength. Max-S1 of all PEEK rests exceeded the PEEK fatigue strength, whereas Max-S1 of the zirconia rests was lower than the zirconia fatigue strength.Conclusions Zirconia occlusal rests with conventional metal rest designs have sufficient fatigue strength. PEEK occlusal rests have insufficient fatigue strength and may not withstand repeated mastication.
目的 我们旨在通过有限元分析评估由聚醚醚酮（PEEK）和氧化锆制成的可摘局部义齿牙合支托。
方法 构建三维PEEK和氧化锆支托模型，包括牙合支托（基部厚度1.5 mm，宽度3.0 mm）和小连接体（厚度1.5 mm，高度6.0 mm），以及具有牙釉质力学性能的支托窝模型。支托与小连接体之间的过渡曲率半径为0.1 - 0.5 mm。支托与支托窝模型界面设置为摩擦接触（μ = 0.1），支托窝模型底部在所有方向上均受约束。在小连接体底面垂直施加100 N向下的载荷。将第一主应力的最大值（Max - S1）与每种材料的抗弯强度和疲劳强度进行比较。分析了厚度为1.0 - 2.0 mm、宽度为2.0 - 3.5 mm、过渡曲率半径为0.5 mm的牙合支托。
结果 Max - S1出现在过渡部位，并随着过渡曲率半径、支托宽度和厚度的增加而减小。厚度至少为1.5 mm且宽度为3.0 mm的PEEK支托的Max - S1低于抗弯强度。所有PEEK支托的Max - S1均超过PEEK疲劳强度，而氧化锆支托的Max - S1低于氧化锆疲劳强度。
结论 具有传统金属支托设计的氧化锆牙合支托具有足够的疲劳强度。PEEK牙合支托的疲劳强度不足，可能无法承受反复咀嚼。
