Xie Min, Xiao Hongxi, Hu Min, Liu Hongchen, Li Yanfeng
Department of Stomatology, 309th Hospital of the People's Liberation Army, Beijing, China.
J Oral Maxillofac Surg. 2012 Dec;70(12):2876-83. doi: 10.1016/j.joms.2012.02.025. Epub 2012 May 24.
The titanium-nickel shape-memory alloy distractor is a new kind of alveolar ridge distraction device that can be completely buried and self-activated. To evaluate this new device, the present study compared the effects of 2 osteotomy techniques and investigated the osteogenesis outcome by measuring the bone mineral density and biomechanical properties of newly generated bone tissues.
Adult mongrel canines (n = 18) were randomly divided into 3 groups. All the mandibular teeth were extracted. Group I received a complete osteotomy, whereas groups II and III received a partial osteotomy with preservation of the glossal cortical bones. The left mandible served as the experimental site for each group, and the right side served as the internal control. Groups I and II were sacrificed 3 months after the completion of distraction, whereas group III was sacrificed 6 months after the completion of distraction. Radiographs were taken. Dual-energy x-ray absorptiometric results and compressive biomechanics of the distracted and control bone masses were examined for groups II and III (partial osteotomy group).
The complete osteotomy group exhibited a larger distraction space initially; however, the distracted area showed a remarkable depression on the buccal-glossal side. In contrast, the partial osteotomy groups exhibited a nearly normal mandibular morphology. The bone mineral density, compressive strength, and elastic modulus were decreased in the distracted side compared with the control side 3 months after distraction. These 3 parameters increased in the distracted side 6 months after distraction, which did not differ significantly from those in the control side.
Partial osteotomy with preservation of the glossal cortical bones is more suitable for alveolar ridge augmentation using the shape-memory alloy distraction device. The newly generated bone exhibited adequate strength, which can satisfy the requirements of subsequent implantation.
钛镍形状记忆合金牵张器是一种新型的牙槽嵴牵张装置，可完全植入体内并自行激活。为评估这种新装置，本研究比较了两种截骨技术的效果，并通过测量新生成骨组织的骨密度和生物力学性能来研究成骨结果。
成年杂种犬（n = 18）随机分为3组。拔除所有下颌牙齿。第一组进行完全截骨，而第二组和第三组进行保留舌侧皮质骨的部分截骨。每组以左侧下颌骨作为实验部位，右侧作为自身对照。第一组和第二组在牵张完成后3个月处死，第三组在牵张完成后6个月处死。拍摄X线片。对第二组和第三组（部分截骨组）的牵张侧和对照侧骨块进行双能X线吸收测定结果及压缩生物力学检查。
完全截骨组最初牵张间隙较大；然而，牵张区域在颊舌侧出现明显凹陷。相比之下，部分截骨组下颌形态接近正常。牵张后3个月，牵张侧的骨密度、抗压强度和弹性模量较对照侧降低。牵张后6个月，牵张侧的这3项指标升高，与对照侧相比差异无统计学意义。
保留舌侧皮质骨的部分截骨更适合使用形状记忆合金牵张器进行牙槽嵴增高。新生成的骨具有足够的强度，能够满足后续种植的要求。
