Chen Fengshan, Terada Kazuto, Hanada Kooji, Saito Isao
Division of Orthodontics, Graduate School of Medical and Dental Sciences, Niigata University, Japan.
Angle Orthod. 2006 Jul;76(4):660-5. doi: 10.1043/0003-3219(2006)076[0660:AEOOVN]2.0.CO;2.
Palatal implants can be used with a transpalatal arch (TPA) connected with the second premolar to provide anchorage. The purpose of this study was to compare the anchorage effects of an osseointegrated palatal implant (OPI) with a nonosseointegrated palatal implant (NOPI), using finite element analysis. One model, which was composed of two maxillary premolars, periodontal ligament (PDL), alveolar bone, a palatal implant, palatal bone, a bracket, band, and TPA, was created on the basis of the clinical situation. The palatal implant was treated as either NOPI or OPI. The force on the premolars was investigated under three conditions: a distomesial horizontal force, a buccolingual horizontal force, and a vertical intrusive force. The PDL stress was calculated and compared with a model without an implant. The result showed that OPI could reduce PDL stress significantly. (The average stress was reduced by 14.44% for the distomesial horizontal force, 60.28% for the buccolingual horizontal force, and 17.31% for the vertical intrusive force.) The NOPI showed almost the same anchorage effect as OPI. The stress on the NOPI surface was higher than that on the OPI surface, but the stress was not high enough to result in failure of the implant. These results suggested that waiting for osseointegration might be unnecessary for an orthodontic implant.
腭部种植体可与连接第二前磨牙的腭弓（TPA）配合使用以提供支抗。本研究的目的是使用有限元分析比较骨结合型腭部种植体（OPI）与非骨结合型腭部种植体（NOPI）的支抗效果。根据临床情况创建了一个模型，该模型由两颗上颌前磨牙、牙周膜（PDL）、牙槽骨、一个腭部种植体、腭骨、一个托槽、带环和TPA组成。腭部种植体被视为NOPI或OPI。在三种情况下研究前磨牙上的力：近中向水平力、颊舌向水平力和垂直压入力。计算PDL应力并与没有种植体的模型进行比较。结果表明，OPI可显著降低PDL应力。（近中向水平力时平均应力降低了14.44%，颊舌向水平力时降低了60.28%，垂直压入力时降低了17.31%。）NOPI显示出与OPI几乎相同的支抗效果。NOPI表面的应力高于OPI表面的应力，但该应力不足以导致种植体失效。这些结果表明，正畸种植体可能无需等待骨结合。
