Khan Abdul Rahman, Fida Mubassar, Sukhia Rashna Hoshang
The Aga Khan University Hospital, Section of Dentistry, Department of Surgery, Karachi 74800, Pakistan.
The Aga Khan University Hospital, Section of Dentistry, Department of Surgery, Karachi 74800, Pakistan.
Int Orthod. 2019 Sep;17(3):497-505. doi: 10.1016/j.ortho.2019.06.009. Epub 2019 Jun 27.
Various treatment modalities are used to treat skeletal Class II malocclusion with different effects on the soft tissue. This study was aimed to determine factors affecting changes in soft tissue profile after various treatment modalities for skeletal Class II malocclusion.
A cross-sectional study was conducted using pre-treatment and post-treatment lateral cephalograms of 141 subjects. The sample consisted of 47 patients treated with Clark's Twin Block, 47 with first premolar extractions, and 47 with Class II elastics. The post-treatment cephalograms were superimposed on pre-treatment radiographs using stable landmarks: anterior wall of sella turcica and anterior cranial base. The changes in profile were evaluated by paired t-test using X-Y co-ordinate system. Changes in profile were predicted by using multi-variable linear regression analysis. Level of significance was kept at P≤0.05.
The changes in soft tissue profile were statistically significant for all the landmarks (P<0.001) of nose, upper and lower lip, and chin in horizontal and vertical direction, except subnasale and labrale superius in the horizontal direction. The soft tissue profile changes can be predicted for all landmarks with various prediction powers except pronasale, subnasale, and inferior labial sulcus in the vertical direction.
Almost all the soft tissue landmarks of nose and lower third of the face exhibit downward and forward movement. The changes in the upper lip in both horizontal and vertical directions were found to be more predictable than those occurring in the lower lip.
多种治疗方式用于治疗骨性安氏II类错牙合，对软组织有不同影响。本研究旨在确定骨性安氏II类错牙合采用多种治疗方式后影响软组织侧貌变化的因素。
采用141名受试者治疗前和治疗后的头颅侧位片进行横断面研究。样本包括47例采用克拉克双阻板矫治器治疗的患者、47例拔除第一前磨牙的患者和47例使用II类牵引的患者。治疗后的头颅侧位片以蝶鞍前壁和前颅底等稳定标志重叠于治疗前的X线片上。采用X-Y坐标系通过配对t检验评估侧貌变化。通过多变量线性回归分析预测侧貌变化。显著性水平设定为P≤0.05。
除鼻下点和上唇唇红缘在水平方向外，鼻、上下唇及颏部所有标志点在水平和垂直方向的软组织侧貌变化均具有统计学意义（P<0.001）。除鼻前点、鼻下点和下唇沟在垂直方向外，所有标志点的软组织侧貌变化均可通过不同预测能力进行预测。
几乎所有鼻部和面部下三分之一的软组织标志点均表现为向下和向前移动。发现上唇在水平和垂直方向的变化比下唇更具可预测性。
