Zepa Katrina, Urtane Ilga, Krisjane Zane, Krumina Gaida
Department of Orthodontics, Institute of Stomatology, Rigas Stradins University, 20 Dzirciema street, Riga, Latvia, LV 1007.
Stomatologija. 2009;11(1):15-20.
To evaluate and compare dimensional morphology of masseter and medial pterygoid muscles and mandibular skeletal parameters between subjects with skeletal Class II and Class III.
The sample consisted of 13 patients with skeletal Class II and 10 patients with skeletal Class III prior to the start of combined orthodontic treatment and orthognathic surgery with correspondence to definite inclusion and exclusion criteria. Magnetic resonance imaging was performed for mandibular muscles and following 2D and 3D measurements were done: cross-sectional area (CSA), thickness, width, longitudinal dimension and volume. 3D multi-slice computed tomography investigation was performed for the assessment of skeletal mandibular parametres and following measurements were done: height of mandibular ramus, length af mandibular corpus, overall mandibular length, intergonial width. All the measurements were done bilaterally. Data were analyzed using descriptive statistics, t-test, and correlation coefficients.
It was found that values of all mandibular and medial pterygoid measurements were higher in Class III subjects with statistical significance (p<0.05). There was a tendency of all masseter variables to be higher in Class III patients. Positive correlations were found between muscles' volume and CSA in both groups, muscles' volume and all mandibular parameters in Class II group, CSAs and all mandibular variables except intergonial width in Class II group. Overall symmetry was observed between left and right sides in all muscular and mandibular measurements in both groups.
The data were acquired using two different imaging techniques - MRI and MSCT that can be mentioned as a novelty in this field of research. Remarkable differences were observed between study groups for both skeletal and muscular measurements.
评估和比较安氏II类与安氏III类受试者的咬肌和翼内肌的维度形态以及下颌骨骨骼参数。
样本包括13例安氏II类患者和10例安氏III类患者，均在开始正畸治疗和正颌手术之前，符合明确的纳入和排除标准。对下颌肌肉进行磁共振成像，并进行以下二维和三维测量：横截面积（CSA）、厚度、宽度、纵向尺寸和体积。对下颌骨骨骼参数进行三维多层计算机断层扫描研究，并进行以下测量：下颌升支高度、下颌体长度、下颌总长度、下颌角间宽度。所有测量均双侧进行。数据采用描述性统计、t检验和相关系数进行分析。
发现安氏III类受试者的所有下颌骨和翼内肌测量值均较高，具有统计学意义（p<0.05）。安氏III类患者的所有咬肌变量均有升高趋势。两组中肌肉体积与CSA之间、安氏II类组中肌肉体积与所有下颌骨参数之间、安氏II类组中CSA与除下颌角间宽度外的所有下颌骨变量之间均存在正相关。两组所有肌肉和下颌骨测量的左右两侧均观察到总体对称性。
数据是使用两种不同的成像技术——MRI和MSCT获取的，这在该研究领域可被视为一种创新。在骨骼和肌肉测量方面，研究组之间观察到显著差异。
