第二磨牙萌出障碍的检出率变化及病因调查

Changes in the Detection Rate and Etiological Analysis of Second Permanent Molar Eruption Disturbances

目的:调查近年相对于二十多年前第二磨牙萌出障碍的检出率变化,并分析病因。方法:以在作者所在医院就诊的患者病历资料为研究对象,并按照就诊年代分为二十年前组和近年组。比较两组第二磨牙萌出障碍的检出率,分析主要病因以及与错牙合畸形类型的关系。结果:近年组的检出率及患牙数明显高于二十年前组(P<0.01)。两组中,由萌出方向异常和或间隙不足而导致的患牙数明显高于其他原因导致的患牙数(P<0.05)。第二磨牙萌出障碍好发于下颌,与第三磨牙存在与否无明显关系。在第二磨牙萌出障碍的病例中,骨性Ⅰ类均角最多见,骨性Ⅱ类多于骨性Ⅲ类,高角多于低角。结论:近年第二磨牙萌出障碍的检出率与二十多年前相比明显增加,主要病因为第二磨牙的萌出方向异常和/或间隙不足。第二磨牙萌出障碍好发于骨性Ⅱ类和高角的患者。

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 relationship 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 disturbances,skeletal typeⅠand average angle were the most common,skeletal typeⅡcases were more common than skeletal typeⅢcases,and high angle cases were more common than low angle cases.Conclusion:The detection rate of second molar eruption disturbances and the number of teeth involved increased significantly when compared 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 classⅡand high angle.