Fudalej Piotr, Artun Jon
National Research Institute for Mother and Child, Warsaw, Poland.
Angle Orthod. 2007 Mar;77(2):199-205. doi: 10.2319/0003-3219(2007)077[0199:MGREOP]2.0.CO;2.
To test the hypotheses that pronounced forward and backward mandibular growth rotation may be risk factors for postretention relapse of mandibular incisor alignment, and that morphologic parameters at adolescence may be predictive of the remaining type of mandibular growth.
Cephalograms and study models were made before (T1) and after (T2) active treatment and at a minimum of 10 years postretention (T3) of three groups of orthodontic patients with acceptable occlusion at the time of appliance removal. The groups were short facial height (n = 46), angle between the sella-nasion line and the mandibular plane (SN/MP) <or= 28 degrees; normal facial height (n = 42), SN/MP 29 degrees through 37 degrees ; and long facial height (n = 35), SN/MP >or= 38 degrees at T2.
The groups were similar regarding age at T2, gender ratio, incisor irregularity (IRI), intercanine (3-3) width at T1, change of 3-3 width from T1 to T2, and time from T2 to T3 (P > .05). IRI increased in all groups from T2 to T3 (P < .05), but there were not any intergroup differences in this increase (P > .05). Minor differences were detected among the groups in mandibular growth rotation from T2 to T3. Males experienced more forward rotation than females (P < .001) and more increase in IRI from T2 to T3 (P < .01). Male gender, T1-T2 increase in 3-3 width, and T2-T3 reduction in 3-3 width were included in the model explaining T2-T3 increase in IRI.
High-angled and low-angled facial patterns at time of appliance removal are not associated with increased risk of postretention relapse of mandibular incisor malalignment, and in adolescent orthodontic patients are poor predictors of type of posttreatment growth.
检验以下假设，即明显的下颌向前和向后生长旋转可能是下颌切牙排列保持后复发的风险因素，以及青少年时期的形态学参数可能预测下颌剩余的生长类型。
对三组正畸患者在积极治疗前（T1）、治疗后（T2）以及保持至少10年后（T3）拍摄头颅侧位片并制作研究模型，这三组患者在去除矫治器时咬合均正常。分组为短面高组（n = 46），蝶鞍 - 鼻根连线与下颌平面夹角（SN/MP）≤28°；正常面高组（n = 42），SN/MP为29°至37°；长面高组（n = 35），T2时SN/MP≥38°。
三组在T2时的年龄、性别比例、切牙不齐度（IRI）、T1时尖牙间（3 - 3）宽度、T1至T2时3 - 3宽度的变化以及T2至T3的时间方面相似（P > 0.05）。从T2至T3，所有组的IRI均增加（P < 0.05），但在这种增加方面没有组间差异（P > 0.05）。在T2至T3的下颌生长旋转方面，组间检测到微小差异。男性比女性经历更多的向前旋转（P < 0.001），并且从T2至T3的IRI增加更多（P < 0.01）。男性性别、T1 - T2时3 - 3宽度的增加以及T2 - T3时3 - 3宽度的减小被纳入解释T2 - T3时IRI增加的模型。
去除矫治器时高角和低角面部模式与下颌切牙排列不齐保持后复发风险增加无关，并且在青少年正畸患者中，对治疗后生长类型的预测性较差。
