去除下颌骨角及体部外侧骨皮质的实验研究

目的 对成年动物去除下颌骨角及体部外侧全层皮质后的局部形态学、生物力学及组织学进行实验性观察研究.方法 8～12个月龄成年小香猪8只,去除一侧下颌骨角及体部外侧全层皮质,随机挑选2只动物,术后12周处死,取骨质标本行组织学检查;另6只动物术后24周处死,测量体部下颌骨外侧皮质厚度、角区骨质行生物力学分析,同时取骨质标本行组织学检查.结果 术后24周,下颌骨实验侧再生的外侧皮质厚度为(2.1±0.3)mm,对照侧外侧皮质厚度为(2.5±0.4)mm,两侧比较差异有统计学意义(P＜0.01);角区生物力学强度,最大载荷实验侧为(401.76±204.91)N,对照侧为(585.42±413.07)N,差异无统计学意义(P＞0.05),刚度实验侧为(2 172.19±1 174.73)N/mm,对照侧为(2 363.90±1 547.48)N/mm,差异无统计学意义(P＞0.05);组织学观察骨质达到完全再生修复.结论 下颌骨外侧全层皮质去除后局部新骨再生,组织学结构可达到完全修复;形态学上体部骨质变薄,局部凹陷,角区可见增生骨结节;对生物力学强度的影响不大.

Experimental study about osteotomy of mandibular outer cortex

Objective To investigate the change of morphology.biomeehanics and histology after osteotomy of mandibular outer cortex.Methods The mandibular outer cortex that involves angle and part of body was removed at one side in 8 minitype pigs aged 8～12 months.2 pigs were selected randomly for histologic examination 12 weeks after operation.The other 6 animals were killed 24 weeks after operation.The thickness of new-formed mandibular outer cortex wag measured and compared with that of operated side.Biomeehanieal test was performed in bilateral angles.Histological observation Wag made in the operated side.Results The thickness of outer cortex was(2.1±0.3)mm and(2.5±0.4)mm in the operated side and opposite side,respectively,showing a significant difference between them(P＜0.01).The maximum load was(401.76±204.91)N and(585.42±413.07)N in the operated side and opposite side,respeetively(P＞0.05).The Rigidity was(2 172.19±1 174.73)N/mm and(2 363.90±1 547.48)N/mm(P＞0.05).There was nostatistical difference in biomeehanics between the two sides.The histologie study showed histologically complete regeneration of outer cortex 24weeks afar mandibular outer cortex osteotemy.Conclusions After rebection of mandibular outer cortex,the histologic resmrafion is complete,but the new-formed outer cortex is thinner with local depression.Bone tubercle can be seen at the aIlgk after bone regeneration.There is no obvious change in biomechanics after outer cortex esteotomy.