Parreiras Ferreira Raquel, Isaias Seraidarian Paulo, Santos Silveira Giordani, Campolina Rebello Horta Martinho, Martin Palomo Juan, Andrade Ildeu
Prosthetic Resident, Department of Restorative Dentistry, School of Dentistry, Pontifical Catholic University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
Associate Professor, Department of Restorative Dentistry, School of Dentistry, Pontifical Catholic University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
Compend Contin Educ Dent. 2020 Apr;41(4):e1-e6.
The authors' objective was to determine, by means of cone-beam computed tomography (CBCT), if there is a significant difference between the cephalometric and condylar measurements obtained in maximum intercuspation (MIP) and those obtained in centric relation (CR), which would interfere in orthodontic diagnosis and planning.
The sample consisted of 30 randomly selected patients (15 men and 15 women, mean age 14 years, CR ≠ MIP between 1 mm and 2 mm) who had undergone orthodontic treatment. This retrospective study used CBCT scans, one in MIP and the other in CR. Cephalometric measurements and sagittal, axial, and vertical condylar variations between the CR and MIP positions were analyzed in a tridimensional (3D) imaging software.
Patients with a small CR-MIP discrepancy (<2 mm) presented significant differences in the cephalometric analysis carried out in CR and MIP, although these differences might be of low clinical significance. The condyle-fossa relationships in sagittal, coronal, and axial planes did not seem to be relevant, because only one measurement presented significant change between CR and MIP positions.
Class II malocclusion in patients with a large CR-MIP discrepancy may be exacerbated in the CR position, which may in turn increase treatment difficulty. In these cases, not only must cephalometrics be registered in CR, but dental casts and photographs of the patient are needed to permit orthodontists to plan an appropriate treatment.
作者的目的是通过锥形束计算机断层扫描（CBCT）来确定，在最大牙尖交错位（MIP）获得的头影测量值和髁突测量值与在正中关系（CR）获得的测量值之间是否存在显著差异，这可能会干扰正畸诊断和治疗计划。
样本包括30名随机选择的接受过正畸治疗的患者（15名男性和15名女性，平均年龄14岁，CR与MIP之间的差异在1毫米至2毫米之间）。这项回顾性研究使用了CBCT扫描，一次在MIP，另一次在CR。在三维（3D）成像软件中分析了CR和MIP位置之间的头影测量值以及矢状、轴向和垂直方向的髁突变化。
CR-MIP差异较小（<2毫米）的患者在CR和MIP进行的头影测量分析中存在显著差异，尽管这些差异可能临床意义不大。矢状面、冠状面和轴位面的髁突-关节窝关系似乎不相关，因为在CR和MIP位置之间只有一项测量呈现出显著变化。
CR-MIP差异较大的患者的安氏II类错牙合在CR位置可能会加剧，这反过来可能会增加治疗难度。在这些情况下，不仅必须在CR状态下记录头影测量值，还需要患者的石膏模型和照片，以便正畸医生制定合适的治疗方案。
