Shetty Preeth, Hegde Amitha M, Rai Kavita
Department of Pedodontics and Preventive Children Dentistry, A B Shetty Memorial Institute of Dental Sciences, Mangalore, Karnataka, India.
J Clin Pediatr Dent. 2009 Fall;34(1):87-93. doi: 10.17796/jcpd.34.1.dv5100j371184087.
The stress distribution patterns within the maxillary complex during the expansion by slow maxillary expansion plate and Nitanium palate expander 2 was analyzed.
This comparative study was done using a finite element model of a young maxillary bone. The model was generated using the data from computerized tomographic scans of a dried maxillary bone. The model was then strained to a dimensional pattern of displacement and stress distribution for the two appliances.
This present study showed the maximum lateral displacement for jack screw by 0.170 mm at the region of cusp tips of posteriors indicating a tipping movement. Whereas NPE2, showed maximum displacement of 0.004 mm corresponding to maxillary molars. Concentration of stress distribution ranging from 343.42 N/mm2 to 412.60 N/mm2 for 0.5 mm of expansion was significantly depicted at the palatal bone beside the central incisors for jack screw, when compared to NPE2 which depicted low magnitude of stress ranging from 7.78 N/mm2 to 9.08 N/mm2 uniformly distributed along the midpalatal suture.
The findings of this study suggests that NPE2 appliance basically an orthodontic appliance however is capable of producing mild to moderate orthopedic changes in maxilla.
分析了使用慢速上颌扩弓板和镍钛腭扩弓器2进行扩弓时上颌复合体内部的应力分布模式。
本对比研究使用了年轻上颌骨的有限元模型。该模型是根据干燥上颌骨的计算机断层扫描数据生成的。然后对该模型施加应变，以获得两种矫治器的位移和应力分布的尺寸模式。
本研究显示，螺旋扩弓器在后部牙尖区域的最大侧向位移为0.170毫米，表明存在倾斜运动。而镍钛腭扩弓器2显示上颌磨牙的最大位移为0.004毫米。与镍钛腭扩弓器2相比，螺旋扩弓器在中切牙旁的腭骨处，对于0.5毫米的扩弓，应力分布集中在343.42牛/平方毫米至412.60牛/平方毫米之间，镍钛腭扩弓器2的应力值较低，在7.78牛/平方毫米至9.08牛/平方毫米之间，沿腭中缝均匀分布。
本研究结果表明，镍钛腭扩弓器2基本上是一种正畸矫治器，但能够在上颌产生轻度至中度的矫形变化。
