目的:本研究的目的是分析不同类型的骨骼III类错牙合伴下颌不对称的患者的三维牙齿代偿,采用锥形束计算机断层扫描(CBCT)和三维重建测量技术,从而为正畸正颌联合治疗提供临床指导和参考。
方法:选择符合纳入标准的81例骨性III类错牙合伴下颌不对称性患者。根据一种新的分类方法,该方法基于相对于波峰偏差的方向和数量,患者分为三组,分别为1型,2型和3型.在类型1中,精神偏离的方向与支偏离的方向一致,并且精神偏离的量大于支偏离的量。在2型中,门神偏离的方向与支偏离的方向一致,门神偏离的量小于支偏离的量。在类型3中,精神偏离的方向与分支偏离的方向不一致。上颌咬合平面(OP),前咬合平面(AOP),在重建的CBCT图像上测量后咬合平面(POP)。垂直的,横向,测量了上颌牙齿到参考平面的前后距离以及这些牙齿的长轴与参考平面之间的3D角度。在每组中比较了从偏离侧和非偏离侧测量的这些牙齿变量,以及彼此之间。
结果:在81例不对称III类错牙合畸形患者中,52名患者分为1型,12名患者分为2型,17名患者分为3型。1型和3型偏侧与非偏侧之间存在显着差异(p<0.05)。在1型中,偏侧上颌牙齿的垂直距离低于非偏侧,AOP,OP,偏离侧的POP大于未偏离侧的POP(p<0.05)。在3型中,偏侧上颌牙齿的垂直距离较低(p<0.05),偏离侧的AOP和OP大于非偏离侧的AOP和OP。在所有三组中,偏侧上颌牙齿距正中矢状面的横向距离大于非偏侧(p<0.05),上颌牙长轴与偏侧正中矢状面的夹角较大,分别为(p<0.05)。
结论:在1型和3型中,观察到偏侧上颌牙齿的萌出高度较小。在类型1中,AOP,POP,OP在偏离侧更大,而在类型3中,只有AOP和OP在偏离侧更大。三组患者的上颌牙在偏侧均为颊侧和颊侧倾斜。仍需要更大的样本观察来进一步验证这些发现。
OBJECTIVE: The purpose of this study was to analyze three-dimensional dental compensation in patients with different types of skeletal Class III malocclusion with mandibular asymmetry, using cone-beam computed tomography (CBCT) and three-dimensional reconstruction measurement technology, thereby providing clinical guidance and reference for combined orthodontic and orthognathic treatment.
METHODS: 81 patients with skeletal Class III malocclusion with mandibular asymmetry were selected in accordance with the inclusion criteria. According to a new classification method based on the direction and amount of menton deviation relative to ramus deviation, patients were divided into three groups called Type 1, Type 2, and Type 3. In Type 1, the direction of menton deviation was consistent with that of ramus deviation and the amount of menton deviation was greater than that of ramus deviation. In Type 2, the direction of menton deviation was consistent with that of ramus deviation and the amount of menton deviation was smaller than that of ramus deviation. In Type 3, the direction of menton deviation was inconsistent with that of ramus deviation. The maxillary occlusal plane (OP), anterior occlusal plane (AOP), and posterior occlusal plane (POP) were measured on reconstructed CBCT images. The vertical, transverse, and anteroposterior distances from maxillary teeth to reference planes and the 3D angles between the long axis of these teeth and reference planes were measured. These dental variables measured from the deviated and non-deviated sides were compared within each group, as well as among each other.
RESULTS: Of the 81 patients with asymmetrical Class III malocclusion, 52 patients were categorized in Type 1, 12 patients in Type 2, and 17 patients in Type 3. There were significant differences between deviated and non-deviated sides in Type 1 and Type 3 (p < 0.05). In Type 1, the vertical distances of maxillary teeth on the deviated side were lower than those on the non-deviated side, and AOP, OP, and POP on the deviated side were larger than those on the non-deviated side (p < 0.05). In Type 3, the vertical distances of the maxillary teeth on the deviated side were lower (p < 0.05), and the AOP and OP on the deviated side were larger than those on the non-deviated side. In all three groups, the transverse distances of the maxillary teeth from the mid-sagittal plane on the deviated side were larger than those on the non-deviated side (p < 0.05), and the angles between the long axis of maxillary teeth and the mid-sagittal plane on the deviated side were larger, respectively (p < 0.05).
CONCLUSIONS: The maxillary teeth on the deviated side were observed to have smaller eruption heights in Type 1 and Type 3. In Type 1, AOP, POP, and OP were greater on the deviated side, while in Type 3, only AOP and OP were greater on the deviated side. The maxillary teeth of patients in all three groups on the deviated side were buccal and buccally inclined. Larger sample observations are still needed to further verify these findings.