未治疗安氏Ⅰ类错（牙合）下颌骨生长发育特点的研究

Mandibular growth in untreated Class Ⅰ malocclusion

目的研究未治疗的安氏Ⅰ类错（牙合）患者下颌骨生长发育特点，为临床上安氏Ⅰ类错（牙合）的治疗提供参考。方法收集安氏Ⅰ类错（牙合）病例909例，按性别和颈椎骨龄（cervical vertebral maturation，CVM）分期分组，通过头影测量片测量不同性别不同颈椎分期患者下颌骨的长度及高度变化，方差分析后进行组间多重对比。结果无论男女SNB、SND角均逐渐增大，但差值并无统计学意义。在CS1-CS2和CS3-CS4期男性下颌骨升支生长量分别为3．54mm、3．70mm，下颌骨水平部生长量分别为3．86mm和4．27mm，下颌骨总长度生长量为6．46mm和6．22mm，增长都很显著（P〈0．01）。女性CS1-CS2和CS3-CS4期间下颌升支生长量为3．42mm和3．00Hun，下颌骨总长度生长为5．94mm和3．69mm，下颌骨水平部在CS1-CS4出现持续增长（P〈0．05）。下面高在CS1-CS4期间出现明显的增长（P〈0．05），但女性在CS4期之后增长缓慢。结论男女性患者下颌骨生长发育高峰期均出现在CS1-CS2和CS3-CS4期，女性下颌水平部在CS1-CS4期呈持续增长。下前面高生长较早，后面高增长较下前面高快，导致下颌平面角减小。

Objective To investigate the characteristics of mandibular growth in untreated Class Ⅰ malocclusion subjects. Methods The sample consisted of 909 subjects with Class Ⅰ malocclusion who were divided into six groups according to their gender and CVM（cervical vertebral maturation）. The length and height of mandible were measured from their cephalograms. The data were analyzed by SPSS18. 0. Results SNB angle and SND angle increased in all groups, but no statistically significant difference was found. During the stage of CS1-CS2, Co-Go, Go-Gn, Co-Gn increased by 3. 54 mm, 3. 86 mm and 6. 46 mm in males, and in females Co-Go, Go-Gn, Co-Gn increased by 3. 42 mm, 2. 94 mm and 5. 94 mm, respectively, and all of them showed statistically significant difference. During the stage of CS3-CS4, Co-Go, Go-Gn, Co-Gn also showed statistically significant increment in males and females, the average value were 3.70 mm, 4. 27 mm and 6. 22 mm in males, 3.00 mm, 1.73 mm and 3. 69 mm in females. The average value of ANS-Me increased from CS1 to CS4, but after CS4 it grew slowly in females. Conclusions The length of mandible had greatest growth in CS1-CS2 and CS3-CS4 in both males and females. The mandibular body length increased significantly from CS1 to CS4. Anterior facial height increased in the earlier stage. Because the posterior facial height increased faster than anterior facial height, the average value of mandibular plane angle decreased.