原子力显微镜检测兔面缝增龄性变化

目的研究兔的前颌缝、鼻额缝、颧颞缝、腭横缝的交错性及纳米弹性性能，及其缝的生物力学特性的增龄性变化，为缝牵引成骨技术的临床应用提供实验依据。方法选取3个月龄及6个月龄同种日本大耳白兔各8只，切取颧颞缝、鼻额缝、前颌缝及腭横缝组织，观察缝大体交错性，并应用原子力显微镜检测缝的微观形貌和生物力学特性，并比较不同年龄组动物之间的差异。结果两组动物的颧颞缝、鼻额缝、前颌缝及腭横缝组织及其相关矿化前缘具有明显不同的交错性、三维微观形貌和弹性材料性能。随年龄的增大、鼻额缝和前颌缝的交错性增加。6个月龄的兔颧颞缝、鼻额缝、前颌缝及腭横缝组织及其矿化前缘表面形貌较3个月龄平滑，而弹性模量则有所增加。结论面缝的微观形貌和弹性模量的增龄性变化提示，大龄上颌发育不全患者可以应用更大的力量进行缝牵引成骨治疗。

Study of aging changes of rabbit facial sutures with atomic force microscope

Objective To determine the effect of aging on sutural interdigitation and nanomechanical properties of facial suture in order to provide a experimental basis for feasibility of applying sutural distraction osteogenesis in different ages. Methods The digital photograghs of the suture specimens was used to measure the degree of sutural interdigitation and the atomic force microcopy with the nanoindentation method was adopted to observe the nanomechanical properties of four facial sutures, pre-maxillomaxillary, the nasofrontal, the zygomaticotemporal , the transverse palaline and their corresponding sutural mineralization fronts in two groups of rab bits （3 month group and 6 month group） were measured and analyzed. Results The marked differences were found in the characteristics of topographic, sutural interdigitation and elastic modulus of the four facial sutures and their corresponding sutural mineralization fronts between two groups. The sutural interdigitation of the nasofrontal and pre-maxillomaxillary was increased with age. Elastic modulus in 6 month rabbits was more slightly higher than the 3 month group, though the topographic in 6 month aged rabbits were smoother than the 3 month aged ones. Conclusion The atomic force microscope can be used to measure the topographic and nanoelastie property of the facial suture in a more natural way which could help us to research the biomeehanieal properties of the sutures. The changes of aging on the characteristics of the topographic and the elastic modulus of the suture may suggest that greater force may be needed for treatment of the maxillary hypoplasia in the older animal.