上颌中切牙与尖牙同时阻生的临床特征分析

Clinical investigation of the maxillary impacted central incisor and ipsilateral canine

目的分析上颌中切牙与同侧尖牙同时阻生病例的临床特征。方法选择上颌中切牙与同侧尖牙同时阻生病例21例,分析上颌中切牙阻生类型与尖牙阻生情况,测量阻生侧及对侧侧切牙发育或萌出异常情况。结果与中切牙阻生同时发生的尖牙76.2%为唇侧阻生,其中完全易位与不完全易位占唇侧阻生尖牙的68.8%,尖牙唇侧阻生病例中侧切牙根远中倾斜和伴牙冠近中倾斜者占87.5%,尖牙唇侧或腭侧阻生病例中,出现锥形或过小等畸形侧切牙的比例分别为31.25%和40.00%。上颌中切牙与尖牙不同阻生类型患者,前牙反牙合比例都超过40%,且多为牙型反牙合。结论与中切牙阻生同时发生的尖牙阻生多为唇侧阻生,与中切牙阻生类型无关,与侧切牙根远中倾斜高度相关,尖牙完全易位与过小或锥形等畸形侧切牙有关。

Objective Toinvestigate the clinical features in patients with impacted maxillary central incisor and ipsilateral canine. Methods Twenty-one cases were selected,with impacted maxillary central incisor and ipsilateral canine.Different patterns of impaction in maxillary central incisors and ipsilateral canines were recorded and analysed. Small /peg-shaped /anomalous lateral incisors and other anomalies were recorded. Lateral incisors angle were measured on the panoramic radiographs. The clinical character of impacted canines were analysed. Results Buccal canine impaction were more often seen（ 76. 2%）,of which 68. 8% were characterized as transposition or incomplete transposition. The ipsilateral lateral incisors were strongly angulated because of more distally located apex rather than mesially tipped crown in 87. 5% buccal canine impaction cases. Small /peg-shaped /anomalous lateral incisors were found in 31. 25% buccal and 40. 00% palatal maxillary canine impaction cases. Anterior teeth crossbites were found in more than 40% cases.Conclusion The impacted maxillary canine occurred after the ipsilateral central incisor impaction were found mostly buccally displaced,with crown and /or apex moving mesially,resulting transposition or incomplete transposition. The obvious distally tipped apex in ipsilateral lateral incisors played a very important role in deviating the eruption path of canines,and anomalous lateral incisors might guide the canine to complete transposition.