CBCT对不同年龄组间下颌第三磨牙拔除风险的评估

Risk Assessment of Mandibular Third Molar Extraction by CBCT in Different Age Groups

目的:运用锥形束CT研究年龄因素对拔除下颌第三磨牙的影响,评价早期拔除下颌第三磨牙的风险性。方法:筛选2015年6~12月在我院就诊患者中符合纳入标准的锥形束CT图像,共选取150颗下颌第三磨牙,其中16~18岁组47颗牙齿,19~24岁组60颗牙齿,24岁以上43颗牙齿,测得3个年龄组中患者的下颌骨体高(a)、下颌骨体剩余高度(b)与下颌骨体高(a)的比值、牙齿至下颌神经管最短距离数据,并分析不同年龄组之间的差异性。结果:下颌骨体高3个年龄组间差异无统计学意义。3组间b/a比值以24岁以上组最大,其次19~24岁组,各组间两两比较均有统计学意义。在牙齿至下颌神经管最短距离方面,19~24岁组和24岁以上组均比16~18岁组大,有统计学意义;而19~24岁组和24岁以上组间无统计学意义。但是,3个年龄组间牙齿与下颌神经管紧密接触比率无统计学差异。结论:3个年龄组中19~24岁组拔除下颌第三磨牙可能相对最合适、风险最小。

Objective：To study the influence of age on extraction of mandibular third molars by cone beam computed tomography,and evaluate the risk of early removal of mandibular third molar.Methods：One hundred and fifty mandibular third molars which met the inclusion criteria were selected from patients in our hospital between June to December 2015,including 47 teeth in 16-18 age group,60 teeth in 19-24 age group,and 43 teeth in 24 age above group.The mandibular height（a）,the ratio of the residuary mandibular height（b）to mandibular height（a）,and the shortest distance between teeth to mandibular canal were measured.The differences between different age groups were analyzed.Results：There was no significant difference in the mandibular height between three age groups.Among three groups,the ratio of b/a of 24 age above group was the largest,followed by 19-24 age group（P〈0.05）.In terms of the shortest distance between teeth to mandibular canal,the 19-24 age group and 24 age above group were larger than 16-18 age group,and there was no significant difference between 19-24 age group and 24 age above group.However,there was no significant difference in the rate of intimate contact between the teeth and the mandibular canal in three age groups.Conclusion：Removal of mandibular third molars in the 19-24 age group may be the most appropriate and least risky.