犬下颌骨高速投射物伤致牙髓间接损伤的超微结构研究

Ultra structural study on indirect injury of dental pulp caused by high speed missile projectile in dogs′ mandible

目的:研究犬下颌骨高速投射物伤导致的牙髓间接损伤的特点。方法:18只实验犬随机分为6组,以直径6.0 mm、质量0.88 g的高速投射物(不锈钢珠)致伤犬右下颌骨体部第四前磨牙根尖下方区域,但不直接伤及牙齿;分别于伤后6 h、24 h、3 d、7 d、2周、4周处死实验犬,用透射电镜分别观察右下颌第四前磨牙、第二前磨牙、左下颌第二前磨牙牙髓的超微结构变化。结果:右下颌第四前磨牙牙髓损伤严重,发生不可逆性坏死改变;右下颌第二前磨牙牙髓损伤相对较轻,且为可逆性改变;左下颌第二前磨牙牙髓仅有轻微一过性损伤。结论:犬下颌骨高速投射物伤导致的牙髓间接损伤具有损伤范围较广,损伤程度随着距离的增加而迅速递减,神经损伤的变化出现较早等特点。

AIM：To investigate the characteristics of indirect injury of dental pulp caused by high speed missile projectile in dogs＇ mandible. METHODS： Eighteen dogs were divided into six groups with random allocation, then a high speed projectile （stainless steel bead,φ6.0 mm,0.88 g） was shot into the body of right mandible（ the region below the fourth premolar） of each dog,but the teeth were not injured directly. The experimental dogs were killed 6 h,24 h, 3 d, 7 d, 2w and 4w later;then the ultrastructural changes of dental pulp of the fourth premolar of right mandible, the second premolar of right mandible and the second premolar of left mandible were observed through transmission electron microscope（TEM）. RESULTS：In the experimental side,dental pulp of the fourth premolar of right mandible was injured seriously, irreversibly ;yet dental pulp of the second premolar of right mandible was injured less seriously,reversibly;in the opposite side, dental pulp of the second premolar of mandible was injured slightly and temporarily. CONCLUSION ：The characteristics in the indirect injury of dental pulp caused by high speed missile projectile in dog mandible are as follows ： the ranges is extensive ; the degree decreases progressively with the distance increasing; changes of nerval injury occur early,etc.