Comparison between two-dimensional and midsagittal three-dimensional cephalometric measurements of dry human skulls

The aim of this study was to compare two- and three-dimensional cephalometric values by using a three-dimensional analysis based on the midsagittal plane. Spherical metal markers were fixed on to the anatomical landmarks of 10 human skulls, which were examined radiographically with conventional lateral cephalograms and cone-beam computed tomographic (CBCT) scans. Preprogrammed analyses calculated the 18 angular and linear two- and three-dimensional cephalometric values. An error study was made to assess the accuracy and reliability of the methods used. Both sets of values were compared using Wilcoxon's signed-rank test. Probabilities of less than 0.05 were accepted as significant. Reliability of the measurements was assessed by intraclass correlation coefficients (ICC) based on absolute agreement. The method error (ME) was tiny (mean ME < 0.61 measuring unit) and reliable (ICC > 0.97). Comparison of the two- and three-dimensional measurements showed that that they were reliable (ICC > 0.88) and that there were no significant differences (P = 0.41-1.00). The values from the cephalometric analyses were comparable and interchangeable when using the midsagittal three-dimensional approach as described.     

Retrospective Analysis of Ponticulus Posticus in Indian Orthodontic Patients-A Lateral Cephalometric Study

Background

The lateral cephalogram is the most common diagnostic radiograph used in clinical orthodontics. Significant cervical spine pathology can be detected on the routine lateral cephalogram. The aim of this study is to sensitize clinicians for examining the cervical area of lateral cephalogram carefully and thus record anatomical variations.

Materials and Methods

The presence and types of ponticuli posticus were investigated on 650 lateral cephalograms which were randomly selected from archived records at AECS Maaruti College of Dental Sciences & Research Centre, Bangalore

Results

The prevalence rate of Ponticulus Posticus in our study was found to be 11.1%. Though there was slight female predominance of 11.7% as compared to 10.4% in males, difference was not statistically significant.

Conclusion

Ponticulus posticus is a common anomaly in the Indian population. If any such anomaly is detected or suspected, it must be documented in the patient''s health record and specialist consultation must be sought. The lateral cephalogram must thus be considered as one of the baseline screening tool for detecting anomalies and pathology in the cervical spine region.     

骨性错（牙合）Ⅱ类和Ⅰ类成人患者颈椎的形态

背景：虽然在国外已经研究过骨性Ⅱ类和正常（牙合）患者颈椎异常发病率,但在国内尚缺乏颈椎异常在不同错（牙合）畸形患者中发病情况的研究。目的：通过分析不同错（牙合）畸形患者的头颅侧位片,观察颈椎异常患者影像学表现,统计颈椎异常在不同错（牙合）畸形中的发生率。方法：骨性Ⅱ类错（牙合）畸形患者93例,男41例（年龄18-40岁）,女52例（年龄22-35岁）,上齿槽座点-鼻根点-下齿槽座点角（ANB）〉5°。骨性Ⅰ类错（牙合）畸形患者45例,男14例（年龄17-38岁）,女31例（年龄20-36岁）,1°〈上齿槽座点-鼻根点-下齿槽座点角（ANB）〈4°。拍摄患者的自然头颅侧位片,分析和统计颈椎异常各亚类在两组中的发生情况。颈椎异常各亚类发生率与头颅侧位片各个测量值进行Logistic回归分析。结果与结论：①颈椎异常的表现类型分为后弓发育缺陷和融合两大类,后弓发育缺陷分为椎弓裂、发育不足两个亚类,融合又可分为寰枕融合和椎体融合两个亚类。骨性Ⅱ类组中颈椎融合占49%,后弓发育缺陷占4%。骨性Ⅰ类组中,颈椎融合占15%,后弓发育缺陷占6%,颈椎融合在两组中差异有显著性意义。②颈椎融合的发生与上齿槽座点-鼻根点-下齿槽座点角（ANB）,上齿槽座点-鼻根点-颏前点角（ANPg）有相关性,而后弓发育缺陷与各个测量值均无相关性。说明颈椎融合有可能与头颅面部矢状向发育方式有关而后弓发育缺陷不受头颅面发育影响。     

Is the tongue position influenced by the palatal vault dimensions?

Summary The influence of the palatal vault dimensions on tongue position is here studied through evaluation of the in‐mouth air cavity (IMAC) volume when the mandible is in maximal intercuspal position. A sample of 35 women (mean age 21·2 ± 1·0) and 15 men (mean age 22·1 ± 0·9) was selected. The sagittal cross‐section area of the IMAC, which is modulated by the tongue position, was measured on lateral cephalograms. Dental casts were used to measure the palatal vault volume, which was defined by the occlusal plane, the hard palate and the posterior face of the second molars. Palatal vault volume allowed deduction of the IMAC volume through a rule of three procedure relating volume to area ratios. No IMAC could be calculated from cephalograms of 10 subjects who had the tongue stuck to the palate. For the 40 other subjects, the IMAC volume was 8·9 ± 4·8 mL. It was 2 mL larger in men (n = 14) than in women (n = 26) and was the largest in skeletal Class III and the smallest in skeletal Class II (P > 0·05). IMAC volume was strongly correlated with palatal vault height but neither with palatal width nor length. It was thus assumed that the height of the palatal vault could influence the most observed position of the tongue but this does not exclude a possible growth influence of the tongue on its surrounding skeletal structures.     

Forsus矫治器治疗年轻成人安氏Ⅱ类错[牙合]下颌后缩的软硬组织变化

目的：评价Forsus矫治器治疗年轻成人安氏Ⅱ类错[牙合]的临床效果。方法：应用Forsus矫治器对13例年轻成人的安氏Ⅱ类下颌后缩畸形患者进行矫治,术前术后进行头影测量及上、下颌尖牙及磨牙间宽度测量分析。结果：SNA、ANB、OJ、OB、OP-SN、FMA、Si-LiPg＇、U1-NA、U1-NAmm、N＇-Sn-Pg＇、Ls-E、Li-E等在治疗后减小,有显著性差异。L1-NB、L1-NBmm、Pg＇-N＇-S、ANS-Me、Pg-Pg＇、S-N＇-Si、上颌牙弓后部宽度在治疗后增大,有显著性差异。SNB、S-N＇-Sn、Go-Pg、Co-Go、上颌牙弓前部宽度、下颌牙弓前部宽度、下颌牙弓后部宽度、上颌第一磨牙远中及压入移动,上面高等无显著性差异。结论：Forsus矫治器能够有效抑制上颌骨的生长,促进下颌骨逆时针旋转生长,使下面高增大,有效治疗安氏Ⅱ类错[牙合],改善磨牙远中关系及下颌后缩的软组织侧貌。适用于年轻成人患者的治疗。     

Sleep and airway assessment: A review for dentists

Introduction: Dentists can be the first professionals to recognize a patient’s potential sleep problem since they typically have more frequent contact with their patients than do physicians. It is important that dentists have a reasonable understanding of sleep disorders and how to assess their patients if they suspect such a problem so that a timely referral can be made or treatment can be provided as appropriate.

Objective: To review the key literature relevant to sleep-disordered breathing (SDB) characteristics and diagnosis, including history, examination, and investigation with an emphasis on radiographic airway analyses.

Conclusion: The authors present a concise explanation of SDB conditions and an outline for thorough patient examination and evaluation, including radiographic airway analyses. Limited two-dimensional and three-dimensional norms exist for adult patients with no SDB and even less so for children. Much more research is needed, particularly in the pediatric population.     

梭曼和毒扁豆碱引起大鼠脑电癫痫波的M和N胆碱能成分

在加拉碘铵麻痹，人工呼吸维持和甲基阿托品预防的大鼠上，梭曼ＦＳ０．１ｍｇ·ｋｇ－１ｉｍ（ｎ＝２４）或毒扁豆碱３０．０ｍｇ·ｋｇ－１ｉｖ（ｎ＝１８）使全部大鼠脑电图（ＥＥＧ）上出现早期持续很短的紧张性癫痫波和随后持续很长的阵挛性癫痫波．中枢＃ＦＳＮ＃ＦＫ受体激动剂烟碱１．０ｍｇ·ｋｇ－１ｉｖ（ｎ＝３８）和中枢Ｍ受体激动剂槟榔碱１５０ｍｇ·ｋｇ－１ｉｖ（ｎ＝４６）或匹鲁卡品３８０ｍｇ·ｋｇ－１ｉｖ（ｎ＝２４）能分别在ＥＥＧ癫痫波的特征，出现时间和持续时间上模拟出上述早期紧张性癫痫波和随后的阵挛性癫痫波．预先小剂量ｉｖ烟碱使中枢Ｎ受体脱敏或给小剂量Ｎ受体拮抗剂美加明保护中枢Ｎ受体后，梭曼只能引起潜伏期较长且持续很久的阵挛性癫痫波．胆碱酯酶抑制剂梭曼和毒扁豆碱较大剂量引起大鼠ＥＥＧ癫痫波可能的机理是过量的乙酰胆碱作用于潜伏期短，容易脱敏的Ｎ受体出现早期持续很短的ＥＥＧ紧张性癫痫波，又作用于潜伏期较长，不容易脱敏的Ｍ受体，出现稍后的ＥＥＧ阵挛性癫痫波     

基于X线的颅面部软组织三维重建及测量分析研究

目的：利用头颅定位X线片实现颅面部软组织的三维重建及测量。方法：同期分次摄取侧位、45°位和正位头颅定位X线片。利用侧位和45°位X线片上相匹配的外加金属标志点,获得颅面部软组织的三维信息,进行颅面部软组织形态的三维重建。在所建面部三维模型基础之上选8个解剖标志点,进行10项测量,并与人群的正常值进行比较研究。结果：利用侧位和45°位的两张X线片,对颅面部软组织实现三维重建。建立了颅面部软组织的三维测量系统,测量结果同正常值相比较,除面宽和下颌宽有较大的差异外,测量值都具有很好的同一性,面部比例指数除去面宽和下颌角宽的影响大多数都有较好的一致性。结论：本系统基于头颅定位X线片实现颅面部软组织的三维重建和测量,为面部畸形的诊断,正颌手术的定量化手术设计,术后疗效评价提供新的技术方法。     

颅面部软硬组织三维模型的研究

目的:利用头颅定位X线片构建颅面部软硬组织的三维模型.方法:在受试者的面部贴金属标志点,同期分次拍摄侧位,45°位和正位头颅定位X线片,基于相关视觉法原理,获得各标志点的三维数据,实现对颅面部软硬组织的三维重建.结果:用两张成45°夹角的头颅定位X线片,对颅面部的软组织和骨组织实现了逼真的三维重建,系统具有4个特点:①...