Bolton指数指导分析先天缺失单个下切牙病例牙量不调

目的 为临床诊治先天性缺失单个下切牙选择适当的矫治方案提供帮助.方法 采用Bolton分析法,计算分析先天缺失单个下切牙病例模拟治疗方案的全牙比及需调整牙量.选择50副先天缺失单个下切牙病例治疗前模型为实验组,选择100副无先天缺牙,无牙量不调的错合畸形病例治疗前模型为对照组.实验组模拟7种治疗方案,对照组模拟6种常规对称拔除双尖牙治疗方案,以对照组相应的全牙比为参照目标分别计算实验组上颌或下颌需调整牙量.结果 当实验组模拟拔除2个上颌双尖牙达到对照组模拟拔除上下4个双尖牙的结果时,上颌或下颌需调整牙量均较多（约9～11 mm）,实验组模拟拔除2个上双尖牙和1个下切牙达到对照组模拟拔除上下4个双尖牙的结果,上颌或下颌需调整牙量均较少（约2～4 mm）.结论 当先天缺失单个下切牙病例设计拔除2个上颌双尖牙和1个下颌切牙的矫治计划时无论上、下颌需调整的牙量较少,临床可根据具体情况优先选择.

Analysis of Tooth-Size in the Cases with Congenital Missing Single Mandibular Incisor

Objective To compare the tooth mass quantity discrepancy needed to be compensated by different treatment plans of extraction of cases with congenital missing single mandibular incisor for the sake of reaching appropriate treatment plan.Methods The sample consisted of 50 plastic models before treatment of cases with congenitally missing single mandibular incisor as experimental group and 100 models before treatment of cases with intact dentition,no malformed teeth and within normal Bolton ratio as control group.The experimental group simulated 7 possible treatment plans of extraction while as the control group go through 6 routine treatment designs of bicuspid extraction.The overall ratio of every treatment plan of all samples of the two groups were calculated.According to the corresponding treatment results of the control group,setting the total ratio of control group as the treatment objective of experimental group,the tooth mass quantity of needed to compensate of the experimental group of upper and lower arch were calculated respectively.Rusults When simulated the treatment plan of extracting two upper premolars and a lower inscor,it was preferable to adjust the tooth mass of lower arch to get the result of the subgroup of extracting four bicuspids of control group,the tooth mass needed to be adjusted in upper or lower arch were reasonably small no matter which treatment result of control group.Conclusion Although congenitally missing one lower incisor often lead to tooth mass discrepancy and make the treatment planning difficult,tooth mass analysis can be helpful in choice making.