Changes in the Detection Rate and Etiological Analysis of Second Permanent Molar Eruption Disturbances
Objective:To investigate the detection rate of second permanent molar eruption disturbances in recent years compared with more than 20 years ago,and to analyze the etiology.Methods:Medical records of patients who were treated in the orthodontic department of the author's hospital were used as the research materials.The patients were divided into the 20-year group and the recent-years group based on the time of their first visit.The detection rate of second molar eruption disturbances between two groups was compared,and the main causes and the relation-ship with malocclusion classification were analyzed.Results:The detection rate and number of teeth involved in the recent-years group were significantly higher than those in the 20-year group(P＜0.01).Significantly more second permanent molars with eruption disturbances were caused by abnormal eruption direction and/or insufficient space than any other reasons(P＜0.05).The second molar eruption disturbances were more common in the mandible and had no significant relationship with the presence or absence of the third molar.In cases of second molar eruption dis-turbances,skeletal type Ⅰ and average angle were the most common,skeletal type Ⅱ cases were more common than skeletal type Ⅲ cases,and high angle cases were more common than low angle cases.Conclusion:The detec-tion rate of second molar eruption disturbances and the number of teeth involved increased significantly when com-pared with those of 20 years ago.The main causes are abnormal eruption direction and/or insufficient space.The second molar eruption disturbances seem to be more common in cases with skeletal class Ⅱ and high angle.
second molar eruption disturbancedetection rateetiologymalocclusion classification
万方数据
维普
