不同安氏错类型病人第三磨牙缺失情况的分析研究

Research on congenital missing of the third molar in patients with different Angle′s malocclusions

目的:探讨第三磨牙先天缺失与错畸形之间的关系。方法:选取我科收治的正畸病人800例,年龄13～23岁。按照Angle错分类法,将样本分属于三类错畸形,通过全景曲面断层片判定第三磨牙先天缺失的情况。对不同错畸形的第三磨牙先天缺失情况进行统计学分析。结果:在全部病人中,第三磨牙先天缺失率以人数计为32.63%、以牙胚数计为18.72%;无论上颌还是下颌,第三磨牙牙胚缺失率与左右侧无关;上颌第三磨牙牙胚的缺失率明显大于下颌(P<0.05);Ⅰ类、Ⅱ类、Ⅲ类错畸形之间第三磨牙的先天缺失无论在上颌、下颌以及全颌间均无统计学意义(P>0.05)。结论:在错畸形病人中,约30%存在一个或数个第三磨牙的缺失;安氏Ⅰ、Ⅱ、Ⅲ类错畸形与第三磨牙先天缺失之间没有直接关联。

AIM： To study the relationship between the congenital missingthird molar and malocclusion. METHODS： Eight hundred patients aged 13 -23 from orthodontic clinic were chosen. Their panoramic radiographs were examined and were classified into three groups according to Angle＇s classification. The data were analyzed by statistic analysis . RESULTS： The incidence of congenital missing of the third molars was 32.63% by the number of people and 18.72% by the number of tooth germs. In both maxillar and mandible, there was no significant difference in the incidence of congenital missing of the third molars between the right and left side. The incidence of congenital absence of the third molar was much higher in maxilla than in mandible （P 〈 0. 05 ）. The incidence of third molar missing had no significant difference among classification Ⅰ, Ⅱ and Ⅲ in the maxilla or mandible （ P 〉 0.05）. CONCLUSION ：Nearly 30% of malocclusion patients have one or more than one tooth missing of the third molars. There is no relationship between malocclusion and the third molar missing.