A three-dimensional cephalometric analysis of Japanese adults and its usefulness in orthognathic surgery: A retrospective study

This study aimed to establish a three-dimensional (3D) cephalometric analysis of craniofacial morphology and discuss its theoretical usefulness in orthognathic patients.Cone-beam computed tomography (CBCT) images of Japanese subjects with skeletal Class I malocclusion before treatment were selected from among 1000 patients so that samples matched a historic 2D cephalometric cohort with normal occlusion using propensity score matching. In each CBCT image, 67 3D measurements were calculated based on manually identified landmarks. The mean and standard deviation of the measurements were calculated and used as the normative range for each sex. To confirm the usefulness of the 3D measurements, pre- and post-treatment CT data of nine jaw deformity patients who underwent orthognathic surgery with two-dimensional planning (2DP) in the past were used. Pre- and post-treatment CT values were evaluated with a paired t-test as well as a Z-score, which was calculated using the aforementioned normative range, and then categorized into five groups (“deteriorated”, “no improvement”, “over-treatment”, “no change”, “improvement”) with ?1 < Z-score < 1 considered normal.Fifty-six patients were matched to normal skeletal 1 subjects. The normative range of 67 items indicating 3D craniofacial morphology of the Japanese was calculated. Postoperatively, the horizontal position of the pogonion to the mid-sagittal plane significantly decreased (p = 0.043) and “improved”; however, the ramus axis on the right side significantly increased (p = 0.005) and “deteriorated”. Maxillary yaw and the horizontal position of the gonion also tended to “deteriorated”.The normative range for the 3D cephalometric analysis in Japanese has been established. Given findings of deteriorated maxillomandibular yawing after surgery when using conventional 2DP, 3D cephalometric measurements should be used when planning jaw positions after surgery for orthognathic patients.     

Craniofacial growth in children with nasal septum deviation: A cephalometric comparative study

Objective

Nasal-breathing impairment has been described as a possible determinant of maxillofacial development in children with adenoids/tonsils hypertrophy. However little is known about the possible influence of nasal septum deviation on craniofacial growth in childhood. We conducted a multicenter cephalometric study to compare skeletal and dental features in children with chronic nasal-breathing obstruction secondary to nasal septum deviation and nose-breathing controls.

Methods

Ninety-eight children (59M, 39F; mean age 8.8 years; age range 7-12 years) with obligate mouth-breathing secondary to nasal septum deviation (group 1) and 98 age- and sex-matched nasal-breathing controls (group 2) were evaluated. Nasal-breathing function was assessed in all patients with clinical history, ENT instrumental examination and anterior active rhinomanometry. Cephalometric parameters were recorded in all subjects.

Results

Patients of group 1 showed a statistically significant increase of upper anterior facial height (N-palatal plane) and total anterior facial height (N-Me) with regards to group 2. The angular relationships of the sella-nasion, palatal, and occlusal planes to the mandibular plane were greater in group 1 in comparison to controls. The gonial angle (Ar-Go-Me), palatal height and overjet were significantly higher in the mouth-breathing group. A significantly retrognatic position of the maxilla and mandible was recorded in group 1 in comparison to group 2. Most mouth-breathing children showed class II malocclusion, while the majority of control subjects presented normal occlusion. The prevalence of cross-bite was higher in group 1 with respect to controls (p = 0.02).

Conclusion

Children with obligate mouth-breathing due to nasal septum deviations show facial and dental anomalies in comparison to nose-breathing controls. Possible physiologic explanations of our findings are reported.     

前牙开畸形颅面形态的分类研究

目的　对前牙开畸形进行分类研究 ,为临床诊断和治疗提供参考。方法　随机选取116例恒牙期前牙开患者 ,借助计算机X线头影测量技术对其颅面软硬组织及气道结构进行测量 ,综合运用多种现代多元统计方法 ,对开畸形的颅面形态进行分类。结果　对年龄、性别、颅面特征等 15 6项指标经聚类和主成分分析精简为 30个变量 ,再通过因子分析提取出 4个因子 (下颌旋转因子、面高因子、牙骨矢状因子和上颌旋转因子 )。采用逐步聚类法对 116例患者的 4个因子得分进行聚类分析 ,将前牙开畸形这一群体分为牙齿槽型开、下颌顺时针旋转型开、长面型开、上颌逆时针旋转型开和骨性Ⅲ类开 5类并归纳出可供临床使用的简单分类方法。结论　对前牙开畸形进行分类在诊断和矫治设计中起着重要作用。     

多曲方丝弓矫治技术的临床应用

目的：通过多曲方丝弓矫治技术的临床运用,分析其矫治特点,探讨其作用机理。方法 用多曲方丝弓矫治技术对II类,III类及开He等30例错He进行矫治。结果 30例错He用此方法进行乔治,均在相对短的时间内取得了明显效果。结论 多曲方丝弓矫治技术能对临床上较难治的病例处理得相对得心应手。     

牙弓狭窄的安氏Ⅱ类Ⅰ分类错畸形的非拔牙矫治

目的　探讨牙弓狭窄的安氏Ⅱ类Ⅰ分类错牙合畸形不拔牙矫治的可能性。方法　对 8例平均年龄为 12 .3岁、7|7未萌出的牙弓狭窄型安氏Ⅱ类Ⅰ分类错牙合畸形病例 ,采用方丝弓固定矫治器扩弓与推上磨牙向后相结合的方法的不拔牙矫治。结果　治疗前后X线头影测量项目的比较显示 ,治疗后上颌中切牙的突度与轴倾度明显改善 ,上下颌骨关系相对协调 ,侧貌明显改善 ,前牙覆牙合覆盖正常 ,磨牙牙合关系Ⅰ类。结论　在一定的适应证下 ,安氏Ⅱ类Ⅰ分类错牙合畸形的不拔牙矫治是可行的     

正畸微种植体支抗对错颌畸形患者牙周细胞炎性因子水平及不良反应的影响

目的探讨正畸微种植体支抗对错颌畸形患者牙周细胞炎性因子水平及不良反应的影响。方法选取2015年1月至2018年1月我院收治的86例错颌畸形患者,随机分为两组各43例。试验组行微型种植体支抗治疗,对照组行传统口外弓支抗治疗。比较两组的矫治完成时间、牙周细胞炎性因子水平以及不良反应发生情况。结果试验组的矫治完成时间为(14.01±2.05)个月,显著短于对照组的(19.98±2.45)个月(P<0.05)。矫治后,试验组的白细胞介素-1β(IL-1β)、肿瘤坏死因子-α(TNF-α)、白细胞介素-6(IL-6)水平均显著低于对照组(P<0.05)。试验组矫治过程中的不良反应总发生率显著低于对照组(P<0.05)。结论正畸微种植体支抗治疗错颌畸形的效果显著,可有效缩短矫治时间,改善牙周炎性微环境,促进牙周组织修复。     

Evaluation of vertical ramus osteotomy for the surgical correction of unilateral mandibular posterior vertical insufficiency: Long-term follow-up results

PurposeUnilateral posterior vertical insufficiency (PVI) is a growth defect of the mandibular condyle that results in a facial asymmetry. Various surgical procedures can be used to elongate the hypoplastic ramus. The aim of this study was to evaluate long-term aesthetic and architectural outcomes of vertical ramus osteotomy (VRO) in patients with unilateral PVI.Materials and methodsPatients operated on with unilateral VRO were included in this retrospective study. Aesthetic and architectural parameters were evaluated on frontal photographs as well as on frontal and lateral cephalograms preoperatively, postoperatively, at 1-year and at the end of the follow-up.ResultsA total of 48 patients were analyzed. The aesthetic assessment revealed significant correction of the chin deviation (CD) and of the lip commissural line tilt after VRO (p1 = 0.0038 and p2 = 0.0067, respectively) with stable results. The architectural analysis revealed significant improvement in the maxillary and mandibular occlusal planes, as well as the chin deviation (p < 0.0001). A tendency to relapse was noted for the mandibular canting and the CD during the follow-up. VRO allowed for a mean mandibular lengthening of 8.39 mm (ranging from 2.5 to 14 mm).ConclusionVRO allows for immediate restoration of the symmetry of the lower third of the face in patients with unilateral PVI. A revisional procedure may be needed due to a tendency for the chin deviation to relapse.