微种植体与邻牙的不同距离对其牙周组织应力分布的影响

Effects of the Micro-Implant-Tooth Distances on Stress Distribution in the Periodontal Tissues

研究微种植体植入位置与邻牙不同距离时,其邻牙牙周组织的应力分布规律,从而找出合适的植入位置。依据CT图像和微种植体的数据,建立含微种植体的上颌前牙整体内收三维有限元模型。托槽与相应的牙齿之间进行绑定,弓丝与每个托槽之间的相互作用考虑为接触。在微种植体和牵引钩上施加1.5 N的正畸力,分析微种植体分别距离第一磨牙0.1 mm、0.55 mm、1 mm、1.45 mm和1.9 mm时,其邻牙牙周组织的应力分布规律。结果表明,随着微种植体到邻牙距离的减小,其牙周组织的应力将逐渐增大,牙槽骨的应力最大增加了1.2倍;且微种植体与邻牙距离较近时,牙周组织将会出现明显的应力集中。因此,在正畸治疗中应尽量让微种植体植入在两邻牙的中间位置。

The stress distributions of the periodontal tissues with different micro-implant-tooth distances were analyzed. The 3D finite element model of the maxillary anterior teeth retraction with micro-implant was developed according to CTimages of a volunteer. The contact elements were used to simulate the interaction between the arch wire and brackets. And the relationships between the brackets and teeth were considered as bonding. The distances between micro-implants and the first molars were 0. 1 mm,0. 55 mm,1 mm,1. 45 mm and 1. 9 mm,respectively. The load valued 1. 5 N corresponding to the clinical treatment was applied on the models. Then the stress distributions of adjacent periodontal tissues with micro-implants were analyzed. It was observed that the stresses of the adjacent periodontal tissues gradually increased when the micro-implant-tooth distances decreased. The maximum stress of the alveolar bone of the 2nd premolar increased 1. 2 times as the distance between the micro-implants and the 2nd premolars was 0. 1 mm. Moreover,the stress concentration was found in the adjacent periodontal tissues for the micro-implant close to the teeth. Therefore,the micro-implant should be located in the middle position between the 2 adjacent teeth during orthodontic treatment.