牵张器结合脱细胞真皮基质增高牙槽嵴新生骨骨密度及生物力学测试实验

Bone density and biomechanics study of alveolar ridge augmentation with titanium nickel shape memory alloy distractor and acellular dermal matrix

目的观察牵张后犬下颌牙槽嵴高度、骨密度及生物力学的动态变化，探讨镍钛记忆合金牵张器结合异种脱细胞真皮基质增高牙槽嵴后对成骨质量的影响。方法健康成年雄性杂种犬12只分为两组，1个月组和3个月组各6只，每只动物下颌骨又分为实验侧和对照侧。建立牙槽嵴萎缩模型后，在一侧下颌行牵张手术，放入脱细胞真皮基质及两个直径1．0mm，复形温度为33℃的“S”形牵张器，该侧为实验侧；另一侧为对照侧，不放脱细胞真皮基质，仅放入同样牵张器行牵张术。术后1、3个月各处死6只实验动物，切取下颌骨标本，用双能x线骨密度仪扫描3个部位，即：牵张间隙上方、下方及牵张间隙，观察其骨密度，使用生物材料实验机测试牵张区骨块抗压强度和弹性模量。结果牵张术后3个月，实验侧骨密度：牵张间隙上方（0．714±0．238）g／cm^2、牵张间隙（0．512±0．435）g／cm^2、牵张间隙下方（0．615±0．043）g/cm^2，最大抗压强度（36．54±7．32）MPa，弹性模量（1674．10±256．43）MPa，均高于对照侧。结论脱细胞真皮基质作为屏障膜，能提高牵张区成骨质量，增加骨强度，在镍钛记忆合金牵张成骨过程中是一种理想的引导骨再生生物膜。

Objective To observe the dynamic changes of bone density and bone strength after alveolar ridge augmentation with Titanium Nickel shake memory alloy （TiNi-SMA） distractor and acellular dermal matrix （ADM）. Methods Twelve adult healthy male dogs were selected. After the animal model of alveolar atrophy was set up, on one side of mandible, two S-shaped distractors were placed. The diameter of S-shaped distractor was 1 mm and the rebound temperature was 33 ℃. The ADM was placed on the distraction gap and fixed by the feet of distractors. The other side was placed only with distractors, serving as control side. Six dogs＇ mandibles were harvested after 1 and 3 months respectively. Dual energy X-ray absorptimetry （DEXA） was used to scan bone density around the distraction gap. Mechanical machine was used to test compression strength and elastic modulus. Results Months after distraction, the bone density of upper distraction gap, distraction gap and low distraction gap were respectively （0. 714 ± 0. 238 ） g,/cm^2, （0. 512 ± 0. 435 ） g/cm^2 and （0. 615 ± 0. 043 ） g/cm^2 on experimental side. The compression strength and elastic modulus were （ 36. 54 ±7. 32 ） MPa and （ 1674. 10 ±256. 43 ） MPa. All of above were higher than those of control side. Conclusions ADM can improve the bone quality, increase bone density and intensity and is an ideal guided bone regeneration （GBR） membrane for alveolar ridge agumentation with TiNi-SMA distractor.