摘要
目的 :早期预测下颌第三磨牙阻生或萌出的一些客观指标 ,为临床治疗方案提供依据。方法 :随机选择 2 68例患者 (共 417颗下颌第三磨牙 ) ,将其随机分为萌出组、阻生组 ,运用曲面断层全景机对下颌第三磨牙的近中倾斜角、萌出水平、牙冠近远中径、牙根形成、磨牙后间隙、磨牙后间隙 牙冠近远中径的比值进行测量分析。结果 :阻生组中 (15 4例 ,2 18颗下颌第三磨牙 )近中倾斜角平均为 15 .64° ,性别之间在统计学上无显著性差异 (P >0 .0 5 )。阻生组磨牙后间隙比萌出组小 ,二者之间在统计学上有显著性差异 (P <0 .0 0 1)。萌出组与阻生组磨牙后间隙 牙冠近远中径的平均值分别为 1.0 5、0 .74(P <0 .0 0 1)。阻生组与萌出组的牙冠近远中径之间无显著性差异。下颌第三磨牙阻生的发生率与近中倾斜角呈正相关 (P <0 .0 1) ,而与磨牙后间隙呈负相关 (P <0 .0 1)。结论 :大多数阻生的下颌第三磨牙磨牙后间隙 牙冠近远中径比值小于 1。由于没有足够的间隙萌出 。
Objective: To investigate variables in third molar and arch dimensions between the subjects with impacted mandibular third molar and those with erupted. Methods: Standardized panoramic radiographs were taken for 268 subjects (140 male and 128 female with 417 mandibular third molars) with an average age of 28.2 years. The radiographic features includingg angulation of tooth, level of eruption , development of root, mesiodistal crown width and retromolar space were studied . Results: Third molar angulation in impacted group(154 subjects with 218 third molar) averaged 15.64° with no significant gender differences. The retromolar space was significantly smaller in the impacted group than that in the erupted group (P<0.001). The average space/crown width ratios in the impacted and erupted groups were 0.74 and 1.05 respectively (P< 0.01 ). The impacted and erupted groups did not differ significantly in respect to mesiodistal diameter of tooth crown. There was a strong positive relationship between frequency of third molar impaction and angulation degree (P<0.01), but the former was inversely associated with retromolar space (P<0.01). Conclusion: The most significant variable related to third molar impaction is inadequate space for tooth eruption. The vast majority of impacted third molars have space/crown width ratios of less than 1.
出处
《实用口腔医学杂志》
CAS
CSCD
北大核心
2002年第6期536-538,共3页
Journal of Practical Stomatology
