Zhang Y X, Wu Y H, Yao D S, Yang J Y, Gao L
Department of Oral Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China.
Department of Pedodontics, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China.
Zhonghua Kou Qiang Yi Xue Za Zhi. 2018 May 9;53(5):344-350. doi: 10.3760/cma.j.issn.1002-0098.2018.05.011.
To compare the influence of extraction and retention of the intruded dogs' teeth on permanent successors. Nine healthy 45-days-old Chinese rural puppies were selected, and six were submitted to the intrusion of the bilateral canine. Intruded teeth on the left side were extracted 30 minutes later and the teeth on the right side were kept in their sockets. After 8 months, all dogs were sacrificed. General observation, periapical radiograph and cone beam CT were used to observe the preoperative and postoperative deciduous teeth, permanent germs and permanent teeth development. The structure and content of successors' enamel were observed by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). In the extraction groups, the enamel hypoplasia was found in 19 permanent successors, ectopic eruption in 2 cases and abnormal teeth were in 19 cases in total (79%). In the retention groups, enamel hypoplasia of the permanent successors occurred in 2 cases, root dilaceration in 6 cases, and ectopic eruption in 5 cases, retained deciduous teeth in 3 cases, and there were 22 abnormal teeth in total (92%). In blank control group, there was no abnormal teeth. The major effect of intruded deciduous teeth on the permanent successors exhibited enamel hypoplasia [85% (41/48)], presented as enamel coloration and enamel defect (=0.416). The intruded deciduous teeth should be removed early in order to reduce the effect on the permanent teeth.
比较乳恒牙列期犬乳切牙的拔除与保留对其恒牙胚的影响。选取9只45日龄健康中国农村幼犬，其中6只进行双侧乳切牙压入实验。压入30分钟后，拔除左侧压入的乳切牙，右侧压入牙则保留于牙槽窝内。8个月后处死所有实验犬，通过大体观察、根尖片及锥形束CT观察术前、术后乳牙、恒牙胚及恒牙的发育情况，采用扫描电子显微镜（SEM）及能谱分析仪（EDS）观察恒牙胚釉质结构及成分。拔除组恒牙胚中，19颗恒牙出现釉质发育不全,2颗恒牙异位萌出，19颗恒牙出现形态异常，共计79%；保留组恒牙胚中，2颗恒牙出现釉质发育不全，6颗恒牙牙根弯曲，5颗恒牙异位萌出，3颗乳牙滞留，22颗恒牙出现形态异常，共计92%；空白对照组恒牙胚均无异常。乳切牙压入后恒牙胚主要表现为釉质发育不全[85%（41/48）]，表现为釉质色泽改变及釉质缺损（P=0.416）。因此，为减少对恒牙胚的影响，乳切牙压入后应尽早拔除。
