Wang Malanie K, Buschang Peter H, Behrents Rolf
Angle Orthod. 2009 Mar;79(2):271-5. doi: 10.2319/022808-118.1.
To describe the mandibular rotation and remodeling of younger children.
The sample included 43 males and 43 females who participated in the Bolton-Brush Growth Study at Case Western Reserve University in Ohio. They were chosen on the basis of having Class I (n = 45) or Class II (n = 41) molar relationships and longitudinal lateral cephalograms at three developmental stages of the dentition: late primary (T1: 5.7 +/- 0.5 y), early mixed (T2: 8.4 +/- 0.6 y), and full permanent dentition (T3: 15.4 +/- 0.5 y). Each subject's cephalograms were traced and four landmarks were digitized. Cranial base and mandibular superimpositions were performed with the use of natural reference structures.
Yearly rates of true rotation, apparent rotation, and angular remodeling showed significant (P < .05) changes throughout. True rotation was moderately correlated with angular remodeling and apparent rotation. Although no significant sex differences in annual rates of rotation were noted, subjects with Class I molar relationships showed significantly more angular remodeling from T2-T3 than did subjects with Class II molar relationships. Rates of true forward rotation were significantly greater with T1-T2 than with T2-T3 (1.3 and 0.7 degrees/y, respectively).
Although significant amounts of true mandibular rotation and angular remodeling occur during childhood and adolescence, true rotation is greatest during the transition from late primary to early mixed dentition.
描述年幼儿童的下颌旋转和重塑情况。
样本包括43名男性和43名女性，他们参与了俄亥俄州凯斯西储大学的博尔顿-布拉什生长研究。根据其磨牙关系为I类（n = 45）或II类（n = 41），以及在牙列三个发育阶段（乳牙晚期（T1：5.7±0.5岁）、混合牙列早期（T2：8.4±0.6岁）和恒牙列期（T3：15.4±0.5岁））的纵向侧位头影测量片来选取这些受试者。对每位受试者的头影测量片进行描图，并对四个标志点进行数字化处理。利用自然参考结构进行颅底和下颌的重叠分析。
整个过程中，真实旋转、表观旋转和角度重塑的年变化率均显示出显著（P <.05）变化。真实旋转与角度重塑和表观旋转呈中度相关。虽然在旋转年变化率方面未观察到显著的性别差异，但I类磨牙关系的受试者从T2到T3的角度重塑比II类磨牙关系的受试者显著更多。从T1到T2的真实向前旋转率显著高于从T2到T3的（分别为1.3度/年和0.7度/年）。
虽然在儿童期和青少年期会发生大量的下颌真实旋转和角度重塑，但在从乳牙晚期到混合牙列早期的过渡阶段，真实旋转最为明显。
