Ismail Shamique F H, Moss J P, Hennessy R
Orthodontic Department, Dental Institute, 3rd Floor, Royal London Hospital, New Road, London E1 1BB, UK.
Am J Orthod Dentofacial Orthop. 2002 Mar;121(3):244-56. doi: 10.1067/mod.2002.121010.
The purpose of this prospective study was to compare the 3-dimensional (3-D) effects on the face of extraction and nonextraction orthodontic treatment in patients with skeletal Class I patterns. The sample of 24 patients included 12 whose treatment included extractions and 12 who were treated without extractions. Pretreatment study casts were assessed to evaluate dental differences between the 2 groups. Pretreatment and posttreatment lateral cephalograms and optical surface scans were also compared. In the lateral cephalometric assessment, the only significant (P <.05) pretreatment difference was lower lip length. Posttreatment, the nasolabial angle and lower lip thickness were significantly different (P <.05). Registration of the average 3-D optical surface scans indicated that, before treatment, the nonextraction group had longer and broader faces by 5 to 7 mm, and the upper lip and labiomental fold were 3 to 5 mm farther forward than in the extraction group. Posttreatment, the nonextraction group still had larger faces, but the difference was smaller. Faces in the extraction group became relatively more protrusive with treatment. The surface shape analysis technique showed that the cheeks were flatter in the nonextraction group at the start of treatment, but this reversed with time. In the extraction group, the concavity of the labiomental fold increased, while the nonextraction group showed no change in this area. The study demonstrates that 3-D optical surface scans offer more data for analysis compared with lateral cephalograms alone. It also highlights the changes that can be detected with surface shape analysis.
这项前瞻性研究的目的是比较骨骼I类错颌畸形患者拔牙和不拔牙正畸治疗对面部的三维（3-D）影响。24名患者的样本包括12名接受拔牙治疗的患者和12名未接受拔牙治疗的患者。对治疗前的研究模型进行评估，以评估两组之间的牙齿差异。还比较了治疗前和治疗后的头颅侧位片以及光学表面扫描。在头颅侧位片评估中，治疗前唯一显著（P <.05）的差异是下唇长度。治疗后，鼻唇角和下唇厚度有显著差异（P <.05）。平均三维光学表面扫描的配准显示，治疗前，不拔牙组的面部更长更宽5至7毫米，上唇和唇颏沟比拔牙组向前3至5毫米。治疗后，不拔牙组的面部仍然较大，但差异较小。拔牙组的面部随着治疗变得相对更突出。表面形状分析技术显示，治疗开始时不拔牙组的脸颊更扁平，但随着时间推移这种情况发生了逆转。在拔牙组中，唇颏沟的凹陷增加，而不拔牙组在该区域没有变化。该研究表明，与单独的头颅侧位片相比，三维光学表面扫描提供了更多用于分析的数据。它还突出了通过表面形状分析可以检测到的变化。
