骨性Ⅰ、Ⅱ、Ⅲ类错殆患者自然头位、颅面形态与颈椎姿势的研究

目的：探讨骨性Ⅰ、Ⅱ、Ⅲ类错殆患者自然头位、颅面形态与颈椎姿势的关系。方法：测量86例8～15岁均角错胎患者自然头位头颅侧位片并对测量项目进行统计分析。结果：颅部水平参考线与真垂线之间的夹角及颅颈角在骨性Ⅱ类错骀最大,骨性Ⅲ类错殆最小。结论：骨性Ⅰ、Ⅱ、Ⅲ类错殆畸形间自然头位及颈椎姿势有显著差别。     

Relationships of sagittal skeletal discrepancy,natural head position,and craniocervical posture in young Chinese children

Objective: The aim of this study was to investigate the relationships of sagittal skeletal discrepancy, natural head position (NHP), and craniocervical posture in young Chinese children with average vertical facial pattern.

Methods: Ninety patients with average Frankfort mandibular plane angle (FH/ML) were classified into skeletal class I, II, and III relationships according to their ANB angle. Cephalometric radiographs in NHP were taken. Variables representing sagittal and vertical craniofacial morphology, head posture, and craniocervical posture were measured and compared.

Results: Subjects in the skeletal class II group showed the largest craniovertical angles and craniocervical angles, while subjects in the skeletal class III group exhibited the smallest craniovertical angles and craniocervical angles, though not all the measurements showed significant differences. The angle formed by the nasion-sella line and the tangent to the posterior border of the mandibular ramus (NSL/RL) was largest in the skeletal class II group and smallest in the skeletal class III group (p?=?0.05).

Discussion: Significant differences exist in NHP and craniocervical posture among skeletal class I, II, and III relationships in young Chinese children. Subjects with skeletal class II relationship tended to exhibit more extended head, and children with skeletal class III relationship often exhibited flexed head.     

Effects of neuromuscular deprogramming on the head position

Objectives:

The aim of this study was to evaluate the effects of the neuromuscular deprogramming of the mandible on the craniocervical position.

Methods:

Participants (n?=?65) were separated into two groups: 25 untreated controls (10 men and 15 women) and 40 patients (17 men and 23 women) and underwent neuromuscular deprogramming with upper occlusal splints for an average of 6 months and 7 days, before orthodontic treatment. Lateral cephalograms were obtained from each subject in the natural head position (NHP), before and after neuromuscular deprogramming. Craniocervical cephalometric analysis was performed to evaluate craniovertical (NSL/VER), craniocervical (OPT/NSL and CVT/NSL), and cervicohorizontal (OPT/HOR and CVT/HOR) angulation, and the angle of the cervical curvature (OPT/CVT).

Results:

After neuromuscular deprogramming, significant changes in three angles — NSL/VER (P<0·001), OPT/NSL (P<0·001) and CVT/NSL (P<0·001) — were found between the two groups. For the cervical spine position, no significant changes were observed.

Conclusion:

The results indicate that neuromuscular deprogramming using occlusal splint causes significant extension of the head.     

Effect of incisor position on the self-perceived psychosocial impacts of malocclusion among Chinese young adults

Objective:To evaluate the impact of the incisor position on the self-perceived psychosocial impacts of malocclusion among Chinese young adults.Materials and Methods:This cross-sectional study included a convenience sample of 17.1- to 22.3-year-old young adults (n  =  1005). The five groups represented were normal occlusion as well as incisor Class I, Class II/1, Class II/2, and Class III malocclusion. For clinical assessment, the incisor relationship was evaluated according to the British Standards Institute Incisor Classification, and the self-perception of dental esthetics was assessed using the Psychosocial Impact of Dental Aesthetics Questionnaire (PIDAQ). Statistical analysis involved the analysis of variance and Tukey multiple-comparison post hoc tests.Results:Psychosocial impacts were different among the five groups for the four PIDAQ domains (P < .001 for all four domains). Statistically significant differences were found between the four malocclusion groups and the normal occlusion group in all four domains (P < .001 for all four domains). Furthermore, statistically significant differences were found between four malocclusion groups.Conclusions:All four malocclusion groups had more severe psychosocial impacts than the normal occlusion group in the four PIDAQ domains. Statistically significant differences were also found between the four malocclusion groups; these malocclusion groups ranked by score, highest to lowest, were Class III, Class II/1, Class II/2, and Class I.     

Effect of cervical headgear wear on dynamic measurement of head position

The aim of this study was to identify the effect of cervical headgear (CHG) wear on dynamic measurement of head posture during walking. Six male and 10 female patients (mean age, 11.9 +/- 1.9 years) who were receiving CHG therapy for correction of a Class II molar relationship as part of their orthodontic treatment were included in this study. Dynamic head posture measurements were recorded using an inclinometer and data logger apparatus during a walking session of 5 minutes. This procedure was repeated before (T1) and after (T2) insertion of CHG. The T1 and T2 measurements were repeated twice at 30-minute intervals. The mean dynamic head posture was calculated for each subject using the collected data. The means of these measurements were statistically compared using a paired t-test. Of the 16 subjects, 14 showed a cranial flexion with CHG wear in relation to T1 (1.4 to 8.9 degrees). The other two subjects showed a cranial extension of -1.6 and -3.8 degrees. The mean values at T1, T2 and T1-T2 were 1.4, -1.8, and 3.1 degrees, respectively, which indicated a mean cranial flexion at T2 in relation to T1. According to the paired sample t-test, there were statistically significant differences between the two measurements of dynamic head posture recorded before and after CHG insertion (P < 0.001). CHG wear causes a significant cranial flexion which may be responsible for its effects on the mandible.     

天津市恒牙早期正常He牙、颌、颅面结构特征研究

目的 探讨天津市恒牙早期正常He儿童的颅面特征。方法 对天津市70名恒牙早期正常He儿童常规拍摄X线头颅侧位片,按Downs、Tweed,Steiner分析法进行计算机测量分析。结果 得出天津市恒牙早期正常HeX线头颅测量值,并与北京、西安、哈尔滨、上海的测量值进行比较。结论 不同地区正常He青少年其X线头影测量的正常值有一定差异。因此不同地区应有各自相应的正常值标准,不应强求国内一致标准。     

正畸治疗前[牙合]架法分析错[牙合]患者髁突位置的临床研究

目的研究错[牙合]畸形患者正畸治疗前在正中关系（centric-relation,CR）位与正中[牙合]（centric-occlusion,CO）位时髁突位置的偏移情况及其影响因素。方法选取76例错[牙合]]畸形患者为研究对象,获取CO位与CR位的咬合关系;利用AD2[牙合]架和髁突移位测量仪记录髁突位置,分析CR-CO位时髁突位置的变化及其相关因素。结果 CR-CO位时,所有患者的髁突出现偏移,最多出现的髁突移位方向是趋于后下,77.6%的髁突偏移超出可接受生理范围,双侧髁突位移量明显呈现不对称性。髁突的移位量与咬合关系改变量无统计学上的相关性,与性别及错[牙合]骨型亦不存在相关关系。结论正畸治疗前有必要分析错[牙合]畸形患者CR-CO位的一致性,必要时转移[牙合]架并从三维方向上更加准确地诊断患者,制定更加合理的治疗计划。     

Finite element analysis of the cranial base in subjects with Class III malocclusion.

Abstract

The association between cranial base morphology and Class III malocclusion is poorly understood. This study analyses local shape- and size differences in cranial base configurations of Class I and Class III subjects, employing finite element (FEM) analysis. Seventy-three prepubertal European-American children with Class III malocclusion were compared to their counterparts with a normal, Class I molar occlusion. Lateral cephalographs were traced, checked and subdivided into age- and sex-matched groups. Thirteen points on the cranial base were identified and digitized, providing a geometrical cranial base representation. Average cranial geometries were scaled to an equivalent size and a FEM analysis, capable of depicting and quantifying local shape- and size-change, employed to highlight regionalized, morphological differences. While the anterior cranial base was more homogeneous for shape-change, significant, localized anisotropy in the posterior regions of the cranial base and around sella turcica was evident. For size-change, areas of negative allometry were located posteriorly, but dilations in the mid- and anterior cranial base also were apparent. It is concluded that morphological alterations within the petro-occipital complex accompanied by changes in the sphenoidal and ethmoidal regions induce deviation from a normal cranial base configuration to one associated with deficient orthocephalization and an appearance of Class III malocclusion.     

头位左倾和右倾变化对咀嚼肌肌电的影响

目的：研究不同的头位变化对咀嚼肌肌电活动的影响。方法：以30例健康正常[牙合]受试者为研究对象，通过肌电图仪（EMG）测试下颌姿势位和牙尖交错位最大紧咬时，5种头位姿势的颞肌前束（TA）、颞肌后束（TP）、咬肌（MM）、二腹肌前腹（DA）的肌电幅值，并对结果进行统计学分析。结果：下颌姿势位和紧咬位时，与正中头位相比，头左倾和右倾状态时咀嚼肌的肌电值变化无显著性差异（P〉0．05）。结论：咀嚼肌在头位左倾和右倾变化过程中所受影响不大。     

高位J钩引起牙根吸收的临床观察

目的:评价标准方丝弓配合高位J钩对正畸治疗中牙根吸收的影响。方法:随机选择60例经过标准方丝弓技术治疗的安氏Ⅰ类或Ⅱ类Ⅰ分类伴上颌前突年轻女性患者,其中30例在内收前牙阶段应用高位J钩配合治疗。治疗前后拍摄全颌曲面断层片,分别测量2组治疗前后上颌4个切牙的牙根吸收等级,并经计算机进行χ2检验。结果:2组正畸治疗后均有明显的牙根吸收,治疗前后牙根吸收等级比较,2组均有显著性差异(P<0.01)。治疗后2组间牙根吸收等级比较,差异也呈显著性(P<0.01),标准方丝弓配合高位J钩组还出现了极重度吸收。结论:标准方丝弓配合高位J钩在正畸治疗中较单纯使用标准方丝弓技术更易产生严重的牙根吸收。     

6～12岁双生女童头影测量中切牙位置遗传作用的纵向分析

目的:明确遗传和环境因素在生长发育过程中对颅面形态的影响。方法:测量89对双生子女童的头颅侧位片。采用混合纵向观察法,最终得到有效双生子对数183对(其中同卵110对,异卵73对)。利用双生子法对切牙位置做遗传和环境作用的纵向统计学分析,采用SPSS13.0软件包对数据进行独立样本t检验。结果:6个切牙位置关系均有显著环境因素作用(P<0.05),角度LI-MP有显著家族遗传因素作用(P<0.05)。结论:单纯的牙位置关系受遗传因素的影响较弱,但遗传对切牙位置的影响需予以重视。     

The difference between registered natural head position and estimated natural head position in three dimensions

This study determined the intra-rater and inter-rater reliability of re-orientating three-dimensional (3D) facial images into the estimated natural head position. Three-dimensional facial images of 15 pre-surgical class III orthognathic patients were obtained and automatically re-orientated into natural head position (RNHP) using a 3D stereophotogrammetry system and in-house software. Six clinicians were asked to estimate the NHP of these patients (ENHP); they re-estimated five randomly selected 3D images after a 2-week interval. The differences in yaw, roll, pitch, and chin position between RNHP and ENHP were measured. For intra-rater reliability, the intra-class correlation coefficient (ICC) values ranged from 0.55 to 0.77, representing moderate reliability for roll, yaw, pitch, and chin position, while for inter-rater reliability, the ICC values ranged from 0.38 to 0.58, indicating poor to moderate reliability. The median difference between ENHP and RNHP was small for roll and yaw, but larger for pitch. There was a tendency for the clinicians to estimate NHP with the chin tipped more posteriorly (6.3 ± 5.2 mm) compared to RNHP, reducing the severity of the skeletal deformity in the anterior–posterior direction.     

Influence of forward head posture on condylar position

There are several reports suggesting that forward head posture is associated with temporomandibular disorders and restraint of mandibular growth, possibly due to mandibular displacement posteriorly. However, there have been few reports in which the condylar position was examined in forward head posture. The purpose of this study was to test the hypothesis that the condyle moves posteriorly in the forward head posture. The condylar position and electromyography from the masseter, temporal and digastric muscles were recorded on 15 healthy male adults at mandibular rest position in the natural head posture and deliberate forward head posture. The condylar position in the deliberate forward head posture was significantly more posterior than that in the natural head posture. The activity of the masseter and digastric muscles in the deliberate forward head posture was slightly increased. These results suggest that the condyle moves posteriorly in subjects with forward head posture.     

口外弓在治疗上牙弓拥挤中的应用

目的：评价口外弓颈牵引推磨牙向远中矫治磨牙前移导致的上牙弓拥挤的临床疗效.方法：对12例磨牙前移的上牙弓拥挤患者,用口外弓推磨牙向远中,结合固定矫治器进行不拔牙矫治,结合X线头影测量分析及模型分析,评价口外弓的治疗作用.采用SPSS13.0统计学软件进行配对t检验.结果：上牙弓拥挤度减少3.0～6.0 mm,平均减少4.52mm（P＜0.05）.拥挤度的减轻主要来自于上颌第一磨牙向远中移动,治疗后Ptm-U6较治疗前减少1.2～3.5 mm,平均减少2.14mm.结论：口外弓推磨牙向远中是有效解决上颌磨牙前移导致的上牙弓拥挤的方法之一.     

The influence of size,specific gravity,and head position on the swallowing of solid preparations

AimTo clarify the influence of size and specific gravity of solid preparations, and the position of healthy volunteers when swallowing, for the purpose of practical use in patient consultation regarding the taking of medicines.Materials and methodsThe paper reports three studies. Volunteers were asked to swallow four different capsules (A, large and heavy; B, large and light; C, small and heavy; D, small and light) in Study 1, two preparations with different positions (upright, horizontal, and chin-down) in Study 2, and two preparations before and after anesthetization of the bilateral lingual and inferior alveolar nerve in Study 3. The oral transit time (OTT) and pharyngeal transit time (PTT) were evaluated with videofluoroscopy.ResultsThe mean OTT became longer in the order of C, D, B, A. The mean PTT showed no statistically significant differences. The swallowing preference of the four preparations ranked by the subjects showed that difference in size but not the difference in specific gravity is a significant factor. In the chin-down position, OTT was shorter for two preparations, compared with the other two positions. The mean OTT for both the A and B preparations was significantly longer after the bilateral lingual and inferior alveolar nerves were anesthetized.ConclusionWhen swallowing solid preparations, a consideration of size and the position will enable ease of swallowing of medicines. This would especially be the case when delivery of the medicines to be taken by the aged suffering from oral hypoesthesia caused by an underlying disease.     

Current trends in headgear use for the treatment of Class II malocclusions

Objective:To investigate American and Canadian orthodontists’ opinions and perceptions on the use of headgear in the treatment of Class II malocclusions.Materials and Methods:An online survey was sent to randomly chosen orthodontists (n  =  1000).Results:The study was completed by 948 orthodontists; 62% of the orthodontists indicated that they were using headgear in their practice. Those who were not using the appliance (38%) reported that this was mainly due to the availability of better Class II correctors in the market and lack of patient compliance. Of those who use headgear, 24% indicated that the emphasis on headgear use during their residency was an influential aspect of their decision making (P < .05). Nearly a quarter of those who do not use headgear reported that learning about other Class II correctors through continuing education courses was an important factor (P < .05). There was no difference between the headgear users and nonusers in the year and location of practice. Compared with previous studies, this study showed a decline in the use of headgear among orthodontists.Conclusions:Despite a decline, more than half of the orthodontists (62%) believe headgear is a viable treatment. Availability of Class II correctors in the market and familiarity with these appliances though continuing education courses are the reasons for the remaining 38% of orthodontists to abandon use of the headgear.     

Long-term skeletal effects of high-pull headgear followed by fixed appliances for the treatment of Class II malocclusions

Objectives:The long-term skeletal effects of Class II treatment in growing individuals using high-pull facebow headgear and fixed edgewise appliances have not been reported. The purpose of this study was to evaluate the long-term skeletal effects of treatment using high-pull headgear followed by fixed orthodontic appliances compared to an untreated control group.Materials and Methods:Changes in anteroposterior and vertical cephalometric measurements of 42 Class II subjects (n = 21, mean age = 10.7 years) before treatment, after headgear correction to Class I molar relationship, after treatment with fixed appliances, and after long-term retention (mean 4.1 years), were compared to similar changes in a matched control group (n = 21, mean age = 10.9 years) by multivariable linear regression models.Results:Compared to control, the study group displayed significant long-term horizontal restriction of A-point (SNA = −1.925°, P < .0001; FH-NA = −3.042°, P < .0001; linear measurement A-point to Vertical Reference = −3.859 mm, P < .0001) and reduction of the ANB angle (−1.767°, P < .0001), with no effect on mandibular horizontal growth or maxillary and mandibular vertical skeletal changes. A-point horizontal restriction and forward mandibular horizontal growth accompanied the study group correction to Class I molar, and these changes were stable long term.Conclusions:One phase treatment for Class II malocclusion with high-pull headgear followed by fixed orthodontic appliances resulted in correction to Class I molar through restriction of horizontal maxillary growth with continued horizontal mandibular growth and vertical skeletal changes unaffected. The anteroposterior molar correction and skeletal effects of this treatment were stable long term.     

Relationships of vertical facial pattern,natural head position and craniocervical posture in young Chinese children

Objective: To investigate relationships of vertical facial patterns, natural head position (NHP), and craniocervical posture in young Chinese children with skeletal Class I relationship.

Methods: Ninety-four patients with skeletal Class I relationship were classified into low, average, and high angle groups according to their mandibular plane angle (NSL/ML). Cephalometric radiographs in NHP were taken. Variables representing vertical and sagittal craniofacial morphology, head posture, and craniocervical posture were measured and compared.

Results: Inclinations of the mandible to the true vertical and cervical column were smallest in the high angle group and largest in the low angle group. Other variables representing head posture and craniocervical posture were largest in the high angle group, smallest in the low angle group. Inclinations of ramus to cervical column were largest in the high angle group and smallest in the low angle group.

Discussion: Subjects with large NSL/ML angles showed extended head and craniocervical posture, while subjects with small NSL/ML angles exhibited flexed head and craniocervical posture.     

Patients offered orthognathic surgery: Why do many refrain from treatment?

AimTo examine factors associated with patients' decision to decline surgery.Material/methodsOf 470 consecutive patients referred to the University of Oslo from 2007 to 2009, a sample of 160 subjects who had not undergone surgery was identified and contacted. 236 operated patients from the same period served as a comparison group. Morphology was assessed from cephalograms and photographs, and the individuals' opinions were recorded using questionnaires.ResultsDentofacial morphology represented normative treatment need and was generally similar except for a higher rate of severe negative overjet in the operated group (p < 0.001). The most prevalent reasons for declining surgery were risks of side effects, the burden of care, and a general reluctance to undergo surgery. Many un-operated subjects were dissatisfied with their masticatory function and dentofacial appearance.ConclusionInformed consent to orthognathic surgery represents a challenge both to the patient and the professional. The findings imply that patients' motives and fears should be explored during consultation and that the information provided should be adapted to the potential risks and benefits related to the actual treatment.