Kachiwala Viral A, Kalha Anmol S, Machado Genevive
College of Dental Sciences, Davangere, Karnataka, India.
Aust Orthod J. 2009 May;25(1):24-9.
The potential for premolar extractions to produce changes in the soft tissue profile after orthodontic treatment is controversial.
To evaluate the soft tissue changes associated with four first premolar extractions in adult females of South Indian ethnicity.
Pre- and post-treatment lateral cephalometric radiographs of 30 adult female patients of South Indian ethnicity with bimaxillary dentoalveolar protrusion, requiring premolar extractions as a part of their orthodontic treatment, were used. The radiographs were traced and changes in three angular and 12 linear measurements measured relative to the perpendicular to the horizontal reference line, 7 degrees down from S-N through S. Correlation coefficients between the changes in the upper and lower incisors and the lip measurements were calculated.
All linear and angular measurements, except for changes in upper and lower lip thickness, B' point and the anterior point on the lower lip, showed statistically significant (p < 0.05) changes with treatment. A significant negative correlation was found between upper incisor change and nasolabial angle change and a significant positive correlation was found between upper incisor change and retraction of the most anterior point on the upper lip.
Extraction of the four first premolars followed by the retraction of incisors reduced the dental and soft tissue protrusion found in adult South Indian females with bimaxillary dentoalveolar protrusion.
正畸治疗后前磨牙拔除导致软组织侧貌改变的可能性存在争议。
评估南印度成年女性拔除四颗第一前磨牙后相关的软组织变化。
使用30名南印度成年女性患者治疗前和治疗后的头颅侧位片，这些患者均为双颌牙牙槽前突，正畸治疗需要拔除前磨牙。对头颅侧位片进行描图，并测量相对于与水平参考线垂直且从S-N经S向下7度的线的三个角度和12个线性测量值的变化。计算上下切牙变化与唇部测量值之间的相关系数。
除上下唇厚度、B'点和下唇前点的变化外，所有线性和角度测量值在治疗后均有统计学意义（p<0.05）的变化。上切牙变化与鼻唇角变化之间存在显著负相关，上切牙变化与上唇最前点的后缩之间存在显著正相关。
拔除四颗第一前磨牙并随后内收切牙可减少南印度成年双颌牙牙槽前突女性的牙及软组织前突。
