颜面不对称畸形的诊断

人类颜面软硬组织往往存在着程度不同的不对称。通过临床检查、Ｘ线分析、照片测量、同位素扫描测定可以获得不对称畸形的形态和程度，从正常的不对称到非正常的不对称尚没有一个区分标准。对于早期Ｈｅ干扰造成的功能怀不对称进行正畸功能性治疗，对一或结构性不对称畸形进行手术治疗已达成共识。     

颜面部不对称畸形的研究进展

颜面部不对称是口腔临床常见的一种畸形,它严重影响病人的身心健康。随着人们对美观需求的增加,对颜面部不对称畸形的研究变得更加迫切,本文针对颜面部不对称畸形的发生率、病因、发生部位、分类及治疗等研究进展作一综述。     

颜面不对称畸形牙弓特征的研究

目的 研究颜面不对称畸形牙弓的形态特征,为临床治疗提供参考。方法 选取４４例颜面不对称畸形病例,测量牙弓宽度并与正常Ｈｅ做ｔ检验。结果 不对称畸形上牙弓双侧狭窄;女性牙弓宽度窄于男性。结论 颜面不对称畸形以侧同时扩弓解除上下牙弓宽度不调。     

成人颜面不对称患者颌面部骨性结构的三维立体分析

目的:通过锥体束CT(cone-beam computerized tomography,CBCT)资料分析颜面不对称患者颌面部骨性结构三维空间位置的改变。方法:对25例成人颜面不对称患者使用CBCT采集颅面部Dicom数据,使用Mimics 10.01对骨组织进行三维重建,并建立三维坐标系。选择描述上颌复合体及下颌骨形态的36个标志点,测量其三维坐标进行统计分析。结果:上颌复合体仅眶下点、梨状孔最外侧点、颧牙槽嵴点、上尖牙颈缘中点、上第一恒磨牙颈缘中点的位置左右侧差异有显著性,其它各点基本对称;下颌骨大部分标志点左右侧在三维方向上均差异显著,仅髁突顶点、下颌孔、下颌角点在某些方向显示出对称性。结论:颜面不对称患者颌面部畸形程度有从上到下逐步加重的趋势,主要表现为下颌骨形态异常,其立体空间结构发生了代偿性的旋转。     

偏侧咀嚼引起的颜面不对称患者牙弓形态分析

目的研究由偏侧咀嚼引起的颜面不对称患者的牙弓形态。方法试验组为20例由于偏侧咀嚼导致颜面不对称的成人患者,对照组为20例正常大学生。制作所有样本的牙模型,确定标志点,定点连线测量,对所得结果进行统计学分析。结果试验组与对照组相比,Spee曲线(非偏斜侧)、侧方覆盖、上颌第一磨牙冠颊舌向倾斜度、下颌第一磨牙冠颊舌向倾斜度差异具有统计学意义(P<0.05);Spee曲线(偏斜侧)差异无统计学意义(P>0.05)。试验组偏斜侧与非偏斜侧的Spee曲线、侧方覆盖、上颌第一磨牙冠颊舌向倾斜度、下颌第一磨牙冠颊舌向倾斜度、上颌尖牙至牙弓中线距离、下颌尖牙至牙弓中线距离、下颌第二磨牙至牙弓中线距离差异均具有统计学意义(P<0.05)。结论颜面不对称患者的上下颌牙弓不对称,同时牙齿位置也有一定程度的代偿。     

正常开闭口时髁突运动的轨迹特征

目的　通过对正常人群下颌运动中髁突运动的测量记录 ,从而确定正常在开闭口运动中髁突的运动特征。方法　正常 38人 ,其中男女各 19人 ,平均年龄 18.7岁。应用CADIAXⅢ型 (Com puterAidedDiagnosisAxiogragh)髁突运动仪 ,记录下颌在各种边缘运动时的髁突运动情况 ,对开闭口时的髁突运动情况加以分析。结果　定性研究结果表明正常髁突运动轨迹对称 ,光滑 ,重复性好。男女性别无显著差异。在大张口时髁突相对于参考位置 (ReferencePosition)的最大位移左侧为 16 .0 2± 4 .2 7mm ,右侧为 16 .33± 5 .6 4mm ,髁突在位移 5mm时的矢状面倾斜度分别为右侧 35 .2 3± 8.18°,左侧 33.10± 8.6 6° ;在水平面内的髁突倾斜度右侧为 - 2 .0 0± 2 .6 7° ,左侧为 0 .39± 2 .18° ,大张口时绞链轴的旋转度 (GAMMA值 )为 2 6 .18± 6 .2 2°。结论　正常髁突运动轨迹有其典型的轨迹特征 ,但也存在较大的个体差异     

颜面部不对称评价研究进展

颜面部不对称在人群中很常见,于正畸科就诊的患者中多出现不同程度的不对称。因此,评价颜面部不对称具有重要的临床价值。本文将从颜面部不对称的评价方法、研究成果、研究展望3个方面简要介绍目前关于颜面不对称评价的研究情况。     

利用锥体束CT对成人颜面不对称患者颌面部三维形态的研究

目的：通过锥体束CT（cone-beam computerized tomography,CBCT）资料分析颜面不对称患者上颌复合体及下颌骨的三维形态特征,以研究其颌面部三维形态的改变。方法：对25例成人颜面不对称患者使用CBCT采集颅面部Dicom数据,使用Mimics10.01对骨组织进行三维重建,选择描述上颌复合体及下颌骨形态的56项指标进行测量及统计分析。结果：梨状孔最外侧点,眶下点,颧牙槽嵴点,上颌尖牙、第一恒磨牙颈缘中点左右不对称;偏斜侧下颌升支、下颌体的长度均小于对侧;偏斜侧下颌升支平面、下颌体平面与矢状面的成角,下颌平面角均小于对侧;下颌角、下颌孔等相关测量项目双侧均有显著性差异。结论：颜面不对称患者颌面部畸形程度有从上到下逐步加重的趋势,主要表现为下颌骨形态异常,其立体空间结构发生了代偿性的旋转。     

基于CBCT成像技术的颜面部不对称分类研究初探

目的　通过锥体束CT(cone beam computerized tomography,CBCT)资料分析颜面不对称患者颌骨的三维形态特征以及其颜面部不对称的发生部位。方法　对20例标准组及41例错牙合畸形患者分别使用CBCT采集颅面部数据,使用Dolphin11.0软件对骨组织进行三维重建,选择上下颌骨的部分标记点进行不对称系数的测量。结果　上颌骨不对称发生率为20.0%,下颌支不对称发生率为50.0%,下颌体不对称发生率为30.0%。安氏Ⅲ类组上颌骨不对称发生率为38.1%,下颌支不对称发生率为47.6%,下颌体不对称发生率为61.9%。安氏Ⅱ类组不对称发生率为20.0%,下颌支不对称发生率为50.0%,下颌体不对称发生率为35.0%。安氏Ⅲ类组中2例（9.5%）患者仅发生上颌不对称。结论　颜面不对称主要表现为下颌骨形态异常,上颌骨不对称通常伴随着下颌骨的不对称,安氏Ⅲ类患者颜面部不对称的发生率较对照组高。     

颜面不对称畸形的分类及矫治（附病例报告）

目的：对颜面不对称畸形进行分类,为临床矫治提供参考。方法：选择４４例颜面不对称病例,男：女＝１５∶２９,平均年龄１３９±２４岁。拍摄头颅正位Ｘ线片,对样本进行分类。结果：本样本分为５类,并根据发病不同部位和表现制定了相应的治疗方案。结论：应根据颜面不对称畸形不同临床表现制定相应的计划进行治疗。     

Facial asymmetry

A case of monostotic, mandibular fibrous dysplasia has been described in a 22-year-old Amerasian male, who had facial asymmetry of approximately 5 years' duration. Foci of ill-defined sclerotic, pagetoid calcifications were seen on routine film. The CT scans demonstrated bone facial and slight lingual expansion of bone with thinning of the cortex. A three-dimensional, enhanced CT film showed that this lesion was greater than 4 cm. The clinical, radiologic, and microscopic features of fibrous dysplasia have been described.     

Facial asymmetry in subjects with skeletal Class III deformity

We investigated the frequency, site, amount, and direction of facial asymmetry in human adults with mandibular prognathism and examined if these characteristics were associated postnatally with cardinal clinical signs that may indicate a predisposition to facial asymmetry. Two hundred twenty young Japanese adults (69 men and 151 women) who exhibited skeletal Class III malocclusions were selected. The sample was divided into a Postnatal Factor Group and a Nonpostnatal Factor Group. The former group included those who had: (1) received orthodontic treatment using a chin cap; (2) exhibited clinical symptoms of temporomandibular joint (TMJ) disorder; (3) reported a history of maxillofacial trauma; or (4) radiographic abnormality of the condyles. Subjects with a deviation of more than 2 mm from the facial midline associated with any of the 4 landmarks (ANS, U1, L1 and Me) were classified as asymmetric and the asymmetry was measured on a postero-anterior (P-A) cephalogram. Radiographic facial asymmetry was found frequently (70%-85%, for Menton), and most obviously in the lower jaw (P < .05). Lateral displacement toward the left side of the face occurred more often than right-sided deviation (P < .001, for Menton). However, the Postnatal Factor Group showed a higher proportion of subjects with lateral deviation toward the right side (P = .0031) and a greater amount (P < .0001) of chin deviation. This was due to the fact that the subjects having TMJ problems as a postnatal factor showed no directional uniqueness in jaw deviation and exhibited a longer distance of deviation.     

Facial asymmetry in patients with cervicobrachial pain and headache

An increasing number of patients are visiting our hospital who have a chief complaint of neck and shoulder pain and/or headache but who do not have temporomandibular disorders (TMD). We carried out this study with a view to comparing the asymmetry of the facial skeleton or expression of such patients with those of healthy subjects. The incidence of such symptoms of patients and healthy subjects was examined by means of questionnaires. Asymmetry of the facial skeleton of patients was investigated by means of posterioanterior (PA) cephalograms. Facial asymmetry was analysed using the frontal view photographs of faces. We found that the patients had a higher incidence of various symptoms, including fatigability and irritability, in addition to neck and shoulder pain and headache, than the healthy subjects did. Both the healthy subjects and the patients had mandibular skeletal asymmetry to some degree, however, there was no significant difference between the two groups. On the other hand, the patients had a greater level of asymmetry of facial expression, chiefly of the lower face, than the healthy subjects did.     

Facial musculoskeletal asymmetry in hemifacial microsomia

Computer-assisted medical imaging--transaxial computed tomography (CT) scans and three-dimensional surface reconstructions--was used to study the muscles of mastication and their osseous origins and insertions in 24 patients with untreated unilateral hemifacial microsomia (HFM). The relationship between the volume of a muscle of mastication and the shape and size of its origin and insertion in such patients varies widely. Comparison of mean volumes of specific muscles documents a statistically significant decrease among patients who have moderate to marked mandibular dysmorphology as compared with those with minimally dysmorphic mandibles. This study supports the hypothesis that the shape and size of the mandible are related to the muscles that originate and insert upon it. However, the variation among individual patients means that assumptions regarding muscle mass and, in turn, function cannot be made regarding an individual patient on the basis of osseous dysmorphology that has been demonstrated on skull radiographs alone.     

Facial asymmetry. The diagnostic challenge

Evaluation of facial asymmetries requires a complete and systematic approach. This clinical examination is supplemented with radiographic studies including panoramic and cephalometric views. For complex cases CT scans are useful. Evaluation of the shape of the cervical vertebrae seen on lateral cephalometric radiographs can be used to predict potential growth in children.     

Facial asymmetry in temporomandibular joint disorders

In order to investigate skeletal deviation in patients with internal derangement of the TMJ, facial asymmetry was examined by the frontal cephalogram and compared with a control group of asymptomatic subjects. It was demonstrated that mandibular lateral displacement in the patients was significantly greater than that in the controls. The degree of displacement was significantly related to the cant of the frontal occlusal plane and the frontal mandibular plane, indicating the reduced vertical dimension of the posterior occlusal level and the ramus height on the mandibular displaced side. It is concluded that facial asymmetry due to mandibular lateral displacement is a relatively common problem in patients with internal derangement of TMJ. The cant of the frontal occlusal plane seems to be an important occlusal characteristic related to temporomandibular joint dysfunction.     

Facial asymmetry quantitative evaluation in oculoauriculovertebral spectrum

Objectives

Facial asymmetries in oculoauriculovertebral spectrum (OAVS) patients might require surgical corrections that are mostly based on qualitative approach and surgeon’s experience. The present study aimed to develop a quantitative 3D CT imaging-based procedure suitable for maxillo-facial surgery planning in OAVS patients.

Materials and methods

Thirteen OAVS patients (mean age 3.5 ± 4.0 years; range 0.2–14.2, 6 females) and 13 controls (mean age 7.1 ± 5.3 years; range 0.6–15.7, 5 females) who underwent head CT examination were retrospectively enrolled. Eight bilateral anatomical facial landmarks were defined on 3D CT images (porion, orbitale, most anterior point of frontozygomatic suture, most superior point of temporozygomatic suture, most posterior-lateral point of the maxilla, gonion, condylion, mental foramen) and distance from orthogonal planes (in millimeters) was used to evaluate the asymmetry on each axis and to calculate a global asymmetry index of each anatomical landmark. Mean asymmetry values and relative confidence intervals were obtained from the control group.

Results

OAVS patients showed 2.5 ± 1.8 landmarks above the confidence interval while considering the global asymmetry values; 12 patients (92 %) showed at least one pathologically asymmetric landmark. Considering each axis, the mean number of pathologically asymmetric landmarks increased to 5.5 ± 2.6 (p = 0.002) and all patients presented at least one significant landmark asymmetry.

Conclusions

Modern CT-based 3D reconstructions allow accurate assessment of facial bone asymmetries in patients affected by OAVS. The evaluation as a global score and in different orthogonal axes provides precise quantitative data suitable for maxillo-facial surgical planning.

Clinical relevance

CT-based 3D reconstruction might allow a quantitative approach for planning and following-up maxillo-facial surgery in OAVS patients.