Assistant Professor, Department of Prosthodontics, Dental Research Institute, Dental and Life Science Institute, School of Dentistry, Pusan National University, Yangsan, Republic of Korea.
Graduate student, School of Mechanical Engineering, Korea University, Seoul, Republic of Korea.
J Prosthet Dent. 2022 Oct;128(4):716-728. doi: 10.1016/j.prosdent.2020.08.042. Epub 2021 Mar 6.
Various kinds of implants of different diameters and connection types are used for patients with a range of bone densities and tooth sizes. However, comprehensive studies simultaneously analyzing the biomechanical effects of different diameters, connection types, and bone densities are scarce.
The purpose of this 3-dimensional finite element analysis study was to evaluate the stress and strain distribution on implants, abutments, and surrounding bones depending on different diameters, connection types, and bone densities.
Twelve 3-dimensional models of the implant, restoration, and surrounding bone were simulated in the mandibular first molar region, including 2 bone densities (low, high), 2 implant-abutment connection types (internal tissue level, internal bone level), and 3 implant diameters (3.5 mm, 4.0 mm, and 4.5 mm). The occlusal force was 200 N axially and 100 N obliquely. Statistical analysis was performed using the general linear model univariate procedure with partial eta squared (η) (α=.05).
For bone tissue, low-density bone induced a larger maximum and minimum principal strain (in magnitude) than high-density bone (P<.001). As the implant diameter increased, the volume of the cancellous bone in low-density bone at the atrophy region (strain<200 με) increased (P<.001). For implant and abutment, the internal bone-level connection type was associated with increased peak stress as compared with the tissue-level connection type (P<.001). For all models, the stress distribution on the implant complex was influenced by implant diameter (P<.001): a decrease in implant diameter increased the stress concentration.
The implant connection type had a greater impact on the stress of the implant and abutment than the diameter. A tissue-level connection was more advantageous than a bone-level connection in terms of stress distribution of the implant and abutment. Bone density was the most influential factor on bone strain. The selection of dental implants should be made considering these factors and other important factors including tooth size.
不同直径和连接类型的各种植入物用于各种骨密度和牙齿大小的患者。然而，同时分析不同直径、连接类型和骨密度对生物力学影响的综合研究很少。
本三维有限元分析研究的目的是评估不同直径、连接类型和骨密度对种植体、基台和周围骨骼的应力和应变分布。
在下颌第一磨牙区域模拟了 12 个种植体、修复体和周围骨骼的三维模型，包括 2 种骨密度（低、高）、2 种种植体-基台连接类型（内组织水平、内骨水平）和 3 种种植体直径（3.5mm、4.0mm 和 4.5mm）。轴向施加 200N 的咬合力，斜向施加 100N 的咬合力。使用单变量一般线性模型分析方法进行统计分析，采用部分 eta 平方（η）（α=.05）。
对于骨组织，低密度骨引起的最大和最小主应变（绝对值）大于高密度骨（P<.001）。随着种植体直径的增加，低骨密度萎缩区域的松质骨体积（应变<200με）增加（P<.001）。对于种植体和基台，与组织水平连接类型相比，骨水平连接类型导致峰值应力增加（P<.001）。对于所有模型，种植体复合体的应力分布受种植体直径的影响（P<.001）：种植体直径减小会增加应力集中。
连接类型对种植体和基台的应力影响大于直径。与骨水平连接类型相比，组织水平连接类型在种植体和基台的应力分布方面更具优势。骨密度是对骨应变影响最大的因素。选择牙种植体时应考虑这些因素以及其他重要因素，包括牙齿大小。
