摘要目的:探讨骨性Ⅲ类青少年不同发育时期上颌骨三维特征并与骨性Ⅰ类比较。方法:本研究为回顾性研究。选取237例青少年，其中骨性Ⅲ类114例，骨性Ⅰ类123例，根据改良颈椎龄分为高峰期前组(T1)、高峰期组(T2)、高峰期后组(T3)。测量分析骨性Ⅲ类和Ⅰ类不同发育时期上颌骨三维特征。结果:①骨性Ⅲ类指标各个发育时期均有性别差异，如上腭长度T1期[男(42.68±1.24)mm，女(41.53±1.39)mm， P＝0.018]、T2期[男(46.06±1.34)mm，女(44.21±1.11)mm， P<0.001]及T3期[男(47.95±1.87)mm，女(46.01±1.22)mm， P<0.001]。②T1期上颌骨三维指标骨性Ⅲ类小于Ⅰ类，如上腭长度T1期Ⅲ类(41.53±1.39)mm，Ⅰ类(46.14±1.67)mm， P<0.001，这种差异持续至T3期，如上腭长度T3期Ⅲ类(46.01±1.22)mm，Ⅰ类(52.72±1.90)mm， P<0.001。 结论:①骨性Ⅲ类男性上颌骨三维特征各时期均大于女性，磨牙颊倾代偿明显，扩弓时应避免骨开窗开裂。②骨性Ⅲ类较骨性Ⅰ类在高峰期前就表现上颌骨三维发育不足，早期干预上颌骨发育可能效果更佳。

abstractsObjective:To explore three-dimensional characteristics of maxilla in different stages of skeletal Class Ⅲ, and to compare with ClassⅠ.Methods:This is a retrospective study. We selected 237 adolescents, including 114 cases of skeletal Class Ⅲ and 123 cases of skeletal Class Ⅰ, and divided them into pre-peak group (T1), peak group (T2) and post-peak group (T3) according to the modified cervical vertebra age. The three-dimensional characteristics of maxilla in different stages of skeletal Class Ⅲ and Class Ⅰ were measured and analyzed.Results:① There were gender differences in skeletal Class Ⅲ indices, such as pre-peak group of palate length [(42.68±1.24) mm for male and (41.53±1.39) mm for female, P=0.018], peak group [(46.06±1.34) mm for male, (44.21±1.11) mm for female, P<0.001] and post-peak group [(47.95±1.87) mm for male, (46.01±1.22) mm for female, P<0.001]. ② The three-dimensional index of maxilla in skeletal Class Ⅲ was smaller than that in Class Ⅰ, such as palatal length in T1 was (41.53±1.39) mm in Class Ⅲ and (46.14 ±1.67) mm in ClassⅠ, P<0.001. This difference lasted to T3 period, with (46.01±1.22) mm in Class Ⅲ and (52.72±1.90) mm in ClassⅠ, P<0.001. Conclusions:① Three-dimensional characteristics of skeletal Class Ⅲ male were larger than female and the compensation of buccal inclination of molars was obvious. Bone fenestration should be avoided during arch expansion. ② Skeletal Class Ⅲ shows underdevelopment of maxilla before peak, early intervention of maxillary development may be more effective.