Lima de Andrade Camila, Carvalho Marco Aurélio, Bordin Dimorvan, da Silva Wander José, Del Bel Cury Altair Antoninha, Sotto-Maior Bruno Salles
Int J Oral Maxillofac Implants. 2017 Mar/Apr;32(2):264-270. doi: 10.11607/jomi.4797.
The aim of this study was to evaluate the influence of implant macrodesign when using different types of collar and thread designs on stress/strain distributions in a maxillary bone site.
Six groups were obtained from the combination of two collar designs (smooth and microthread) and three thread shapes (square, trapezoidal, and triangular) in external hexagon implants (4 × 10 mm) supporting a single zirconia crown in the maxillary first molar region. A 200-N axial occlusal load was applied to the crown, and measurements were made of the von Mises stress (σ) for the implant, and tensile stress (σ), shear stress (τ), and strain (ε) for the surrounding bone using tridimensional finite element analysis. The main effects of each level of the two factors investigated (collar and thread designs) were evaluated by one-way analysis of variance (ANOVA) at a 5% significance level.
Collar design was the main factor of influence on von Mises stress in the implant and stresses/strain in the cortical bone, while thread design was the main factor of influence on stresses in the trabecular bone (P < .05). The optimal collar design able to produce more favorable stress/strain distribution was the microthreaded design for the cortical bone. For the trabecular bone, the triangular thread shape had the lowest stresses and strain values among the square and trapezoidal implants.
Stress/strain distribution patterns were influenced by collar design in the implant and cortical bone, and by thread design in the trabecular bone. Microthreads and triangular thread-shape designs presented improved biomechanical behavior in posterior maxillary bone when compared with the smooth collar design and trapezoidal and square-shaped threads.
本研究旨在评估在使用不同类型的颈部和螺纹设计时，种植体宏观设计对上颌骨部位应力/应变分布的影响。
从两种颈部设计（光滑型和微螺纹型）与三种螺纹形状（方形、梯形和三角形）的组合中获得六组，用于上颌第一磨牙区域支持单个氧化锆冠的外六角种植体（4×10 mm）。对冠施加200 N的轴向咬合负荷，并使用三维有限元分析测量种植体的冯·米塞斯应力（σ）以及周围骨的拉应力（σ）、剪应力（τ）和应变（ε）。通过单因素方差分析（ANOVA）在5%的显著性水平下评估所研究的两个因素（颈部和螺纹设计）各水平的主要影响。
颈部设计是影响种植体中冯·米塞斯应力以及皮质骨中应力/应变的主要因素，而螺纹设计是影响松质骨中应力的主要因素（P < 0.05）。能够产生更有利应力/应变分布的最佳颈部设计是皮质骨的微螺纹设计。对于松质骨，在方形和梯形种植体中，三角形螺纹形状的应力和应变值最低。
应力/应变分布模式受种植体和皮质骨中的颈部设计以及松质骨中的螺纹设计影响。与光滑颈部设计以及梯形和方形螺纹相比，微螺纹和三角形螺纹形状设计在上颌后牙区表现出更好的生物力学性能。
