【摘要】 目的研究正常(牙合)青少年从替牙期到恒牙初期切牙和第一恒磨牙转矩度的生长变化,为正畸诊断、治疗方案设计提供依据。方法对北京大学口腔医学院·口腔医院颅面生长发育中心收集的20名正常(牙合)青少年样本(男性6名,女性14名)替牙期和恒牙初期的牙颌模型进行分析:替牙期:第一恒磨牙及4颗恒切牙萌出至(牙合)平面,研究对象平均(9.5±0.9)岁;恒牙初期:除第三磨牙外其他恒牙均萌出至(牙合)平面,研究对象平均(13.7±1.3)岁。使用 Biaggini Rayset 系统测量切牙和第一恒磨牙的转矩度,分析替牙过程中牙冠倾斜度的变化。结果替牙期与恒牙初期相比,男、女切牙和磨牙的转矩度差异均无统计学意义(P>0.05)。替牙期至恒牙初期,上颌中切牙转矩度由14°减小为10.9°(P<0.001);下颌中切牙转矩度由1.8°增加为5.2°(P<0.01);上颌侧切牙转距度的变化无统计学意义(P>0.05);下颌侧切牙转矩度由1.2°增加为3.0°(P<0.05)。上颌第一恒磨牙转矩度由-6.6°减小为-10.3°(P<0.001)。下颌第一恒磨牙转矩度由-38.6°增加为-33.2°(P<0.001)。结论从替牙期到恒牙初期,上颌第一恒磨牙逐渐舌向直立,下颌第一恒磨牙逐渐颊向直立。更多还原

【Abstract】 Objective To investigate the longitudinal changes in crown inclination of permanent incisors and first molars in juveniles with normal occlusion.Methods The untreated sample comprised 20 subjects(6 males and 14 females)with normal occlusion from the Research Centre for Craniofacial Growth and Development of Peking University School and Hospital of Stomatology.Crown inclination was evaluated with Biaggini Rayset in two stages,stage Ⅰ with first molars and four incisors in occlusion(mean,9.5± 0.9 years)and stage Ⅱ with the second molars in occlusion(mean,13.7±1.3 years).Results No significant difference was found between sexual groups.The crown inclination of the upper central incisors decreased(P<0.001).The crown inclination of the lower central and lateral incisors increased(P<0.01 and P<0.05,respectively).The crown inclination of maxillary molars decreased with growth(P<0.001), whereas that of mandibular molars increased with growth(P<0.001).Conclusions Maxillary molars tended to become upright lingually,whereas mandibular molars upright buccally with growth.更多还原