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目的调查黑龙江地区恒牙列早期第二恒磨牙各种错畸形的发病率情况及分布规律。方法随机抽取13~15岁中学生3 600人进行调查。结果在3 600个样本中,1 854个存在第二磨牙错畸形,发病率为51.50%,其中男性占52.27%,女性占47.73%。上颌第二磨牙错颊向错位比率最高,占52.96%。下颌则以舌向错位比率高,占53.01%。在第二磨牙错畸形中,安氏Ⅰ类、Ⅱ类和Ⅲ类所占比率依次为48.76%、26.54%和24.70%,第一磨牙咬合关系为反的发病率占2.75%。结论在恒牙列初期第二磨牙错畸形的发病率很高,并且在调查中屡次出现第一磨牙关系为反,影响青少年的颌骨的生长发育,应该引起患者及医生的重视。
Objective To investigate the incidence and distribution of various malformation deformities in the second permanent molars of the permanent dentition in Heilongjiang Province. Methods A random sample of 3 600 middle school students aged 13 to 15 years were investigated. Results Of the 3 600 samples, 1 854 had malformations of the second molars, with an incidence rate of 51.50%, of which 52.27% were male and 47.73% were female. Maxillary second molars wrong cheek to the highest malocclusion ratio, accounting for 52.96%. Jaw is the tongue to the malposition rate is high, accounting for 53.01%. In the second molar malformation deformity, the proportions of Class Ⅰ, Class Ⅱ and Class Ⅲ were 48.76%, 26.54% and 24.70%, respectively, and the occlusal relationship of the first molar was 2.75%. Conclusions The incidence of malocclusion in the second molars is very high in the early stage of permanent dentition. In addition, the first molars recurrence during the investigation is reversed, which affects the growth and development of the mandible of young people and should be paid more attention to by patients and doctors.