Sundareswaran Shobha, Vijayan Ravisankar
Department of Orthodontics, Government Dental College, Kozhikode, Kerala, India.
Indian J Dent Res. 2017 Sep-Oct;28(5):530-537. doi: 10.4103/ijdr.IJDR_549_15.
To prospectively evaluate soft and hard tissue responses to orthodontic treatment of bimaxillary protrusion (BMP) in Dravidian population using McLaughlin, Bennett, and Trevisi (MBT) mechanics of the preadjusted edgewise appliance.
Thirty-one adult (18-30 years) Class I BMP patients were treated using the above mechanics after extraction of four first premolars. Forty-five pre- and post-treatment variables on lateral cephalograms were compared using paired t-test and Pearson's correlation coefficient.
All linear and angular parameters pertaining to hard and soft tissues showed significant changes, indicating retraction of incisors, upper and lower lips; increase in nasolabial angle; and decrease in circumoral convexity, interlabial gap, and lip thickness. Various correlations established were (1) upper lip to upper incisor retraction 1:2.01, (2) lower lip to upper incisor retraction 1:1.5, (3) lower lip to lower incisor retraction 1:1, and (4) upper incisor retraction to nasolabial angle 1:2.02.
Orthodontic therapy using MBT mechanics is very useful in achieving favorable hard and soft tissue changes, following four first premolar extractions in BMP. The various correlations established between incisor retraction and soft tissue parameters could prove useful to the discerning clinician.
采用预成方丝弓矫治器的麦克劳林、贝内特和特雷维西（MBT）矫治技术，前瞻性评估德拉威人群双颌前突（BMP）正畸治疗的软硬组织反应。
31例成年（18 - 30岁）Ⅰ类BMP患者在拔除4颗第一前磨牙后采用上述矫治技术进行治疗。使用配对t检验和皮尔逊相关系数比较头颅侧位片上45个治疗前后的变量。
所有与软硬组织相关的线性和角度参数均有显著变化，表明切牙、上唇和下唇后缩；鼻唇角增大；口周凸度、唇间隙和唇厚度减小。建立的各种相关性为：（1）上唇与上切牙后缩比例为1:2.01，（2）下唇与上切牙后缩比例为1:1.5，（3）下唇与下切牙后缩比例为1:1，（4）上切牙后缩与鼻唇角比例为1:2.02。
在BMP患者拔除4颗第一前磨牙后，采用MBT矫治技术进行正畸治疗对于实现良好的软硬组织变化非常有用。切牙后缩与软组织参数之间建立的各种相关性可能对有洞察力的临床医生有用。
