牵引成骨对牙胚生长发育影响的初步观察

目的:通过对3例下颌骨截骨牵引延长过程的观察,研究牵引成骨对牙胚生长发育及萌出的影响。方法:共有8例小下颌畸形患者接受了下颌骨截开牵引延长治疗以矫治小下颌畸形。其中3例患儿的下颌截骨线上有尚未萌出的牙胚。3例中6侧下颌骨最大牵引延长幅度为22.5mm,最小幅度14mm。在截骨前后、牵引前后及随访过程中X线纵向随访观察,研究牙胚的位置改变及其生长发育的变化过程。结果:经过7～12个月的随访,发现所有在截骨线上或附近的尚未萌出牙胚,在截骨间隙牵开扩大后牙胚将移至牵引间隙中,而且能正常地生长发育、萌出。新骨的沉积钙化速度及新骨成熟所需时间与其他病例无明显差异。结论:手术应避免损伤截骨线上及邻近的尚未萌出的牙胚;在颌骨截开牵引延长的过程中,牵引成骨将不影响牙胚的生长发育,牙胚可以在经牵引形成的新骨中正常地生长发育及萌出;截骨间隙中牙胚的存在不影响新骨的形成。

A PRELIMINARY EVALUATION OF THE EFFECTS ON THE DEVELOPMENT OF DENTAL GERMS IN MANDIBULAR DISTRACTION OSTEOGENESIS

Purpose: To study the effects on development of the dental germs on the osteotomy line during the elongation of mandible by distraction osteogenesis(DO).Methods: There were 8 cases of micrognathia resulted from temporomandibular joint ankylosis received the management of mandibublar elongation by distraction osteogenesis. In 3 of the cases, there were dental germs on the osteotomy line in the mandible. The range of the distraction distance we gained in 3 cases was from 14mm to 22.5mm. Radiographs were taken preoperation and postoperation to observe the development of the dental germs.Results: After a period of follow up(range 7-12 months) we found that all of the dental germs on the osteotomy line developed very well in the enlarged distraction gaps and the teeth erupted from the new bone as normal. There was no significant difference of DO consolidation period between the cases with and without dental germs in the distraction gaps.Conclusions: Injury of the dental germs should be avoided during the operation of mandibular osteotomy and fixation of the distracter. Distraction osteogenesis and the development of dental germs on the osteotomy lines will not be affected by each other.