颏形态综合分析在颏部水平截骨整形术中的应用

目的探讨分析小颏畸形的颏部形态特征及其在颏部水平截骨整形手术应用中的效果。方法通过头颅正侧位X线头影测量分析12例小颏畸形患者的颏部形态,按测量值与正常值之间的差值,计算截骨段移动范围,手术采用颏部水平截骨整形手术方法。结果12例患者均按照术前预测值移动截骨段,术后头颅正侧位X线头影测量结果与术前预测值相近,治疗效果满意。结论通过头颅正侧位X线头影测量分析小颏畸形的特点,精确计算截骨段的移动范围和方向,是保证颏部水平截骨整形术达到良好美容效果的基础。     

Cephalometric image analysis and measurement for orthognathic surgery

Automatic identification of landmarks in cephalometry is very important and useful for orthognathic surgery. A computerised automatic cephalometric analysis system (CACAS), based on image processing, is presented. For an original X-ray image, median filtering and histogram equalisation are used to improve image quality. The edge of an X-ray image is detected by a wavelet transform and Canny filter. Seventeen landmarks in cephalometry are successfully identified by knowledge-based edge tracing and changeable templates. Seventy-three measurements based on distances, angles and ratios between landmarks are computed automatically. The reliability of the landmarks and the validity of the measurements are compared for automatic and manual operation. The values of measurements obtained by CACAS are more precise and reliable: the mean error for linear measurements is less than 0.9 mm; the mean error for angular measurements is less than 1.2°. The rate of validity is over 80%, even if the image quality is poor. For an image with a high signal-to-noise ratio, the rate of validity of landmarking and measurements using the CACAS system is over 90%.     

山东省正常?少年儿童X线头影测量的Steiner分析

目的：建立山东省正常?少年儿童X线头影测量Steiner分析法的均值和标准差,并研究其颅面结构的性别差异、地域差异及增龄性变化。方法：按正常?标准选择156名山东省正常?少年儿童,拍摄X线头颅定位侧位片，采用Steiner分析法进行定点及测量，进行男女间，替牙期与恒牙初期之间的比较。并与哈尔滨和广州地区恒牙初期儿童正常值比较。结果：得到了山东省正常?少年儿童Steiner分析法的正常值;女性下颌骨整体有后缩趋势,男性从替牙期到恒牙初期?平面倾斜度变缓；与哈尔滨人相比，山东人的上颌相对前突；而与广州人相比，广州人的双颌更加前突。结论：用Steiner分析法测得的正常值男女间、替牙期与恒牙期之间均存在差别，不同地区人群头影测量值也存在差别。     

颌间Ⅲ类矫形力对青春期恒河猴上颌骨作用的头影测量研究

目的：通过建立颌间Ⅲ类矫形动物实验模型,评价持续的颌间Ⅲ类矫形力对上颌骨的作用及动态变化规律。方法：选用青春生长发育期雌性恒河猴6只,分为实验组（3月、6月各2只）和对照组（3月、6月各1只）,实验组戴用Ⅲ类双阻板磁力矫治器,对照组不戴。实验过程中,定期拍摄X线头颅侧位片,图像输入计算机头影测量系统进行测量分析。结果：（1）与对照组相比,实验组位发生明显改变;（2）头影测量表明,对照组表现为向下向前发育,实验组矫形治疗后上颌骨相对于颅骨发生了向前的移位和少量旋转,同时其长度出现增加;（3）发现上颌骨的空间位置变化主要发生在开始矫治的两个月内,长度增加的最大值出现在第三个月左右;（4）上颌骨对矫形力作用的反应有一定的限度,增加矫形力作用时间并不能进一步促进上颌骨的更多空间变化和长度的增加。结论：Ⅲ类矫形力可以显著改变上颌骨的空间位置和固有长度,空间的位移比长度的改变出现得早。     

Validity of 2D lateral cephalometry in orthodontics: a systematic review

Lateral cephalometric radiography is commonly used as a standard tool in orthodontic assessment and treatment planning. The aim of this study was to evaluate the available scientific literature and existing evidence for the validation of using lateral cephalometric imaging for orthodontic treatment planning. The secondary objective was to determine the accuracy and reliability of this technique. We did not attempt to evaluate the value of this radiographic technique for other purposes. A literature search was performed using specific keywords on electronic databases: Ovid MEDLINE, Scopus and Web of Science. Two reviewers selected relevant articles, corresponding to predetermined inclusion criteria. The electronic search was followed by a hand search of the reference lists of relevant papers. Two reviewers assessed the level of evidence of relevant publications as high, moderate or low. Based on this, the evidence grade for diagnostic efficacy was rated as strong, moderately strong, limited or insufficient. The initial search revealed 784 articles listed in MEDLINE (Ovid), 1,034 in Scopus and 264 articles in the Web of Science. Only 17 articles met the inclusion criteria and were selected for qualitative synthesis. Results showed seven studies on the role of cephalometry in orthodontic treatment planning, eight concerning cephalometric measurements and landmark identification and two on cephalometric analysis. It is surprising that, notwithstanding the 968 articles published in peer-reviewed journals, scientific evidence on the usefulness of this radiographic technique in orthodontics is still lacking, with contradictory results. More rigorous research on a larger study population should be performed to achieve full evidence on this topic.     

Cephalometric and three-dimensional assessment of the posterior airway space and imaging software reliability analysis before and after orthognathic surgery

PurposeThis study aimed to compare the reliability of three different imaging software programs for measuring the PAS and concurrently to investigate the morphological changes in oropharyngeal structures in mandibular prognathic patients before and after orthognathic surgery by using 2D and 3D analyzing technique.Material and methodsThe study consists of 11 randomly chosen patients (8 females and 3 males) who underwent maxillomandibular treatment for correction of Class III anteroposterior mandibular prognathism at the University Hospital in Zurich. A set of standardized LCR and CBCT-scans were obtained from each subject preoperatively (T0), 3 months after surgery (T1) and 3 months to 2 years postoperatively (T2). Morphological changes in the posterior airway space (PAS) were evaluated longitudinally by two different observers with three different imaging software programs (OsiriX^® 64-bit, Switzerland; Mimics^®, Belgium; BrainLab^®, Germany) and manually by analyzing cephalometric X-rays.ResultsA significant increase in the upper airway dimensions before and after surgery occurred in all measured cases. All other cephalometric distances showed no statistically significant alterations. Measuring the volume of the PAS showed no significant changes in all cases. All three software programs showed similar outputs in both cephalometric analysis and 3D measuring technique.ConclusionA 3D design of the posterior airway seems to be far more reliable and precise phrasing of a statement of postoperative gradients than conventional radiography and is additionally higher compared to the corresponding manual method. In case of Class III mandibular prognathism treatment with bilateral split osteotomy of the mandible and simultaneous maxillary advancement, the negative effects of PAS volume decrease may be reduced and might prevent a developing OSAS.     

Soft tissue thickness in young north eastern Brazilian individuals with different skeletal classes

The aim of this study was to evaluate the variation in facial soft tissue thickness in young north eastern Brazilian individuals according to gender and skeletal class. Measurements were obtained from digitized teleradiographs of 300 children, aged from 8 to 12 years, using the Sidexis Xg program. Data of mean, standard deviation, maximum and minimum soft tissue thickness values of the faces of Angle's Class I, II and III individuals, were evaluated. The results demonstrated that there was no difference in soft tissue thickness among the skeletal classes for most of anthropological points. For the Class I, statistical differences were found (P < 0.05) between the genders in the rhinion point, subnasal and upper lip. It was concluded that there was no difference in soft tissue thickness among the skeletal classes, except between Class II and III for the points: Stomion, Bottom lip and Pogonion, allowing definition of parameters of this population for the purpose of facial reconstruction.     

The interaction of obesity and craniofacial deformity in obstructive sleep apnea

Objective:Both obesity and craniofacial deformity are important etiologies of obstructive sleep apnea (OSA). The present research aimed to explore their interaction and different impacts on OSA severity.Methods:A total of 207 consecutive OSA patients (169 males, 38 females) were included in the research. Based on the body mass index (BMI) value, patients were divided into 77 normal-weight patients (BMI <24 kg m⁻²), 105 overweight patients (24 ≤ BMI<28 kg m⁻²) and 26 obese patients (BMI ≥28 kg m⁻²). All accepted overnight polysomnography and standard lateral cephalogram. Cephalometric measurements involved 25 cephalometric variables. The correlations between these cephalometric variables, BMI and the apnea-hypopnea index (AHI) were evaluated.Results:For the whole sample after controlling for gender and age, stepwise regression analysis showed that the factors affecting AHI were increased BMI, narrowing posterior airway space, inferior displacement of hyoid and elongation of the tongue. When grouped by BMI, normal-weight group exhibited with more reduced maxillary length and mandible length, and steeper mandible plane than overweight and obese patients (p < 0.0167). Obese group showed least skeletal restriction and most prominent soft tissues enlargement (p < 0.0167). However, these skeletal indexes were not statistically correlated with AHI.Conclusions:Obesity and skeletal malformations were both etiological factors of OSA, but obesity seemed to have a greater influence on AHI severity in all kinds of obese and thin OSA patients. Only in normal-weight group, it was affected by both cephalometric variables and BMI.     

Minimally-invasive anterior maxillary distraction technique in patients with cleft lip and palate and maxillary deficiency: an evaluation of 106 patients

Our aim was to evaluate the feasibility of a minimally-invasive surgical technique for anterior maxillary distraction osteogenesis to correct maxillary hypoplasia in patients with clefts. A modified Y distractor was placed intraorally in 106 patients with cleft- associated maxillary deficiency to facilitate protraction of the maxilla. Subsequently the patients had an anterior maxillary osteotomy through a minimally invasive incision, followed by activation of the appliance at the rate of 0.8 mm/day until positive overjet was achieved. The patient’s lateral cephalograms were evaluated preoperatively (T1), after activation (T2), and one year postoperatively (T3). Collected data were assessed with the paired t test, and probabilities of < 0.001 were accepted as significant. A mean (SD) of 10.4 (2.58) mm anterior maxillary advancement was obtained in all patients after 10-13 days of distraction. The sella–nasion-point A (SNA) angle increased from 75.37° to 83.01°. When we compared the cephalometric variables at T1 and T2, the mean maxillary length and overjet at T2 were significantly higher (p < 0.001). The comparison of mean values at T2 and T3 was not significant. Minimally invasive anterior maxillary distraction with the modified Y distractor resulted in changes after activation that were consistent one year postoperatively, making it a conservative, less traumatic, and effective treatment of cleft-related maxillary deficiency.