安氏Ⅲ类错的遗传流行病学研究

目的本文通过对安氏Ⅲ类错的家庭聚集性、遗传度及遗传方式的研究,探讨遗传因素在安氏Ⅲ类错发生中的地位和作用。方法采用遗传流行病学病例对照的研究方法,对195个安氏Ⅲ类错先证家系和208个对照家系进行调查,比较其一级亲属患病率,以二项分布(p+q)n的数学模型及χ2检验判定家庭聚集性。以Falconer回归法进行遗传度的估算。结果安氏Ⅲ类错先证组一级亲属患病率为27.83%,与对照组8.09%相比,统计学上差异具有显著性。二项分布显示,先证组实际频数大于二项分布的理论频数,说明其具有家庭聚集性。一级亲属遗传度为80.85%,其中男性遗传度为90.79%,高于女性遗传度(71.08%)。结论安氏Ⅲ类错的发生具有明显的家庭聚集性,属于多基因遗传模式。其一级亲属遗传度为80.85%,遗传倾向有明显的性别差异。遗传因素在其发病中起重要作用,尤其对男性作用更为明显。     

恒牙列早期安氏Ⅲ类错患者下颌边缘运动轨迹的研究

目的定量定性分析恒牙列早期安氏Ⅲ类错患者下颌边缘运动轨迹的特征及其与颅面形态的关系。方法选择恒牙列早期安氏Ⅲ类错患者21例作为试验组,20例恒牙列早期个别正常人作对照组,使用K6_I型下颌运动描记仪描记两组研究对象的下颌边缘运动轨迹,同时拍摄X线头侧位片,分析二者的相关性。结果试验组下颌边缘运动范围与对照组无统计学意义。对照组ICP_最大张口线距与前下面高呈正相关,开口度与下颌支高度及后面高呈正相关;试验组ICP_最大张口线距与前下面高及下前牙牙槽高度呈正相关,开口度与下颌体长度及下前牙牙槽高度呈正相关。结论安氏Ⅲ类错患者的下颌边缘运动与颅面形态的关系和个别正常人不同。     

骨性安氏Ⅰ、Ⅲ类错舌骨位置的对比研究

目的 :对比骨性安氏Ⅰ类及骨性安氏Ⅲ类早期恒牙患者的舌骨位置。方法 :选取骨性安氏Ⅰ类及骨性安氏Ⅲ类错患者 ,每组 30例 ,对其头颅侧位片上舌骨的位置进行比较分析。结果 :与安氏Ⅰ类错者相比 ,安氏Ⅲ类错者的舌骨位置更靠前 ,且与下颌平面呈顺时针方向旋转关系。结论 :舌骨的位置变化与下颌骨的位置改变有关。     

34例成人安氏Ⅲ类错的正畸效果评价

目的探讨成人安氏Ⅲ类错患者的正畸要求以及效果。方法将近5年来完成的安氏Ⅲ类错的34例成人患者的年龄、求治动机、矫治方法及满意度分别进行调查和统计分析。结果患者的矫治动机以改善美观为主(70.59%),矫治方法以不拔牙矫治占多数(55.88%),患者与医生的满意度基本一致。结论成人安氏Ⅲ类错患者的治疗有其特殊性,应根据成人的要求以及具体情况制定矫治计划。     

牵引弓联合前牵引治疗安氏Ⅲ类错畸形的临床分析

目的探讨替牙早期及恒牙早期两个不同矫治时机对治疗安氏Ⅲ类错的影响。方法选择26例安氏Ⅲ类错牙合患者,牵引弓联合前方牵引6个月,术前术后进行头影测量分析。结果26例患者的上颌骨移位均有显著性变化,SNA增大2.2°±0.3°,A点前移3.3mm±1.3mm,上中切牙切端唇向移动3.8mm±1.2mm,其中替牙早期组表现更多的骨骼、更少的牙齿改变。结论牵引弓联合前方牵引是简便、有效的安氏Ⅲ类错治疗装置,在替牙早期比恒牙早期取得更为显著的治疗效果。     

骨性安氏Ⅲ类错的遗传度分析

目的:探讨遗传因素在骨性安氏Ⅲ类错牙合发病中的作用。方法:应用病例对照研究方法,对96例先证者和200例对照及其亲属资料进行遗传流行病学研究。先证者的诊断标准为:ANB<0°,前牙反牙合,不能后退至前牙对刃,下前牙舌倾。采用SPSS11.5统计软件包对所得数据进行χ2检验。结果:骨性安氏Ⅲ类错牙合先证者一级亲属患病率为9%,二级亲属患病率为1.88%,对照一级亲属患病率为0.96%。一级亲属患病率>二级亲属患病率>对照一级亲属患病率。一级亲属的遗传度为0.74±0.092。分离分析认为,该病不属于常染色体隐性遗传。结论:骨性安氏Ⅲ类错牙合具有多基因遗传病的特点,遗传因素在其发病中起着重要作用。     

前方牵引治疗早期安氏Ⅲ类错后的软硬组织变化

目的研究应用面具式前方牵引矫治安氏Ⅲ类错畸形患者,治疗前后软硬组织变化及相互关系。方法应用面具式前方牵引矫治疗18位安氏Ⅲ类错畸形患者,最短6个月,最长12个月;比较治疗前后的临床表现及头影测量结果。结果矫正后的硬组织改变主要为SNA角的增大和ANB角的增大以及U1-NA的增大,提示上颌骨前部向前生长,前牙唇倾。软组织改变主要为鼻唇角、FCA角和上唇突度的增加。结论面具式前方牵引能够促进上颌骨前部向前生长,抑制下颌骨前部向前生长,同时,随着骨组织的改变软组织侧貌美观相应得到改善。     

骨性安氏Ⅲ类错危险因素的病例对照研究

目的：探讨安氏Ⅲ类错颌的危险因素,为骨性安氏Ⅲ类错的预防提供科学依据。方法：采用病例-对照研究方法,对2003～2009年度西安交通大学口腔医院收治的312例骨性安氏Ⅲ类错病例和344名健康对照者作为研究对象,对研究对象及其亲生父母进行统一的问卷调查,对所有研究因素经单因素分析和二项分类Logistic回归分析,筛选出与骨性安氏Ⅲ类错发生相关的危险因素。骨性安氏Ⅲ类错的诊断标准为：第一恒磨牙为近中关系,前牙反。结果：按α=0.05水准,用x2检验对32个研究因素进行单因素分析,初步筛选出11个可疑危险因素,再经二项分类Logistic逐步回归法,进行多因素分析,最终筛选出与骨性安氏Ⅲ类错发生相关的5个危险因素,分别是腭裂、咬上唇、一级亲属家族史、乳前牙反、人工喂养。结论：骨性安氏Ⅲ类错与遗传因素和环境因素关系密切,应采取综合措施加强预防。     

安氏Ⅲ类错伴有下颌偏斜者颌面部不对称性研究

目的 :通过头颅正位片的测量 ,揭示安氏Ⅲ类错伴有下颌偏斜者颌面在水平向及垂直向不对称的特点。方法 :早期恒牙 ,安氏Ⅲ类错伴有下颌偏斜患者 4 0名 ,治疗前的正位片与 4 0名正常者进行比较 ,用SPSS统计软件处理数据。结果 :下颌骨及下牙弓宽度增大 ;偏斜侧上颌基骨宽度及上下牙弓宽度大于对侧 ;偏斜侧下颌综合长度及下颌体长度小于对侧 ,差异均有显著性意义。结论 :面部不对称主要表现在面下 1/ 3及牙弓区 ;下颌不对称主要发生于下颌的水平部     

未治疗安氏Ⅰ类错（牙合）下颌骨生长发育特点的研究

目的研究未治疗的安氏Ⅰ类错（牙合）患者下颌骨生长发育特点,为临床上安氏Ⅰ类错（牙合）的治疗提供参考。方法收集安氏Ⅰ类错（牙合）病例909例,按性别和颈椎骨龄（cervical vertebral maturation,CVM）分期分组,通过头影测量片测量不同性别不同颈椎分期患者下颌骨的长度及高度变化,方差分析后进行组间多重对比。结果无论男女SNB、SND角均逐渐增大,但差值并无统计学意义。在CS1-CS2和CS3-CS4期男性下颌骨升支生长量分别为3．54mm、3．70mm,下颌骨水平部生长量分别为3．86mm和4．27mm,下颌骨总长度生长量为6．46mm和6．22mm,增长都很显著（P〈0．01）。女性CS1-CS2和CS3-CS4期间下颌升支生长量为3．42mm和3．00Hun,下颌骨总长度生长为5．94mm和3．69mm,下颌骨水平部在CS1-CS4出现持续增长（P〈0．05）。下面高在CS1-CS4期间出现明显的增长（P〈0．05）,但女性在CS4期之后增长缓慢。结论男女性患者下颌骨生长发育高峰期均出现在CS1-CS2和CS3-CS4期,女性下颌水平部在CS1-CS4期呈持续增长。下前面高生长较早,后面高增长较下前面高快,导致下颌平面角减小。     

A longitudinal study of condylar growth and mandibular rotation in untreated subjects with class II malocclusion

Condylar growth intensity, mandibular growth rotation, and the association between growth intensity and rotation were evaluated in 32 untreated subjects with Class II malocclusions. Condylar growth was measured on serial lateral head films annually from ages 8 to 13. The analysis showed that the growth intensity of the condyles varied only slightly between girls and boys, with boys growing more. Fluctuations in growth intensity were observed in all subjects from year to year. None of the individuals maintained a consistent growth velocity over two or more consecutive years. The average condylar growth intensity was two to three mm per year throughout the period from age 8 1/2 to 12 1/2 for both sexes, with boys growing slightly faster than girls at some ages. The greatest growth velocity observed was eight mm in one year, which was seen in one boy. Three girls had as much as six mm of condylar growth in one year. Average mandibular rotation was -0.8 (+/- 0.5 SD) per year in boys and -0.6 degrees (+/- 0.6 SD) in girls, with great individual variation for both sexes. Ninety percent of the subjects showed some degree of anterior or forward rotation; only one subject demonstrated posterior rotation and three demonstrated almost no rotation. No clear relationship was found between amount of condylar growth and mandibular rotation. This study shows that condylar growth intensity varies considerably between subjects and from year to year in each subject, and suggests that clinicians need to be conservative when estimating treatment length for a patient with a Class II malocclusion.     

未治疗安氏Ⅰ类错殆软组织特点及其生长发育特点的研究

的：研究未治疗的安氏I类错殆患者软组织特点及其生长发育特点,为l临床上安氏I类错殆的治疗提供参考。方法：收集安氏I类错殆病例909例,按性别和CVM分期分组,通过头颅侧位片测量不同性别,不同颈椎分期患者软组织厚度和方向的改变,SPSS18．0方差分析后进行组间多重对比。结果：男性ULP、LLP、H角、FCA、H线与鼻、鼻唇沟及颏唇沟的距离基本都大于女性。鼻唇角大小正常,但性别差异显著。男女性患者在FCA和H线与鼻、鼻唇沟、颏唇沟的距离生长发育趋势大体相似。H线与鼻部的距离逐渐减小,男性上唇突度在CSl-CS4期逐渐增大,女性在CSl-CS3期逐渐增大,无明显统计学意义,但女性生长发育早于男性。结论：在CSl-CS6期,男性软组织厚度基本大于女性,鼻唇角性别差异较大。男女性别在软组织生长发育方向趋势上大体相似,但女性软组织生长发育早于男性。     

The management of class III and class III tendency occlusions using headgear to the mandibular dentition

The use of extra-oral traction to the lower arch in the treatment of Class III malocclusion is described. The results of the treatment of 43 consecutive cases employing both removable and fixed appliances are analysed and compared with an untreated control group of 15 further cases. It was found that the Class III malocclusion in the study fell into three groups, the characteristic of each group giving an indication of the recommended treatment approach.     

The clinical characteristics of mandibular fractures in middle-aged and elderly subjects

The authors analyze case histories of 642 patients aged over 50 years with mandibular fractures, treated in 1988-1998 at Clinic for Maxillofacial Surgery of Russian State Medical University. Multiple fractures occurred in patients with mandibular adentia 1.5 times more often than in patients with teeth. The sites of fractures were different in patients with intact occlusion and in those without teeth. Contrary to the traditional opinion, the study showed a high incidence of open mandibular fractures in patients both with and without teeth. Inflammatory complications develop more often than in other age groups, which refers this category of patients to high risk group and requires improvement of methods for their treatment.     

Dentoalveolar changes related to mandibular forward growth in untreated Class II persons

The purpose of this study was to investigate dentoalveolar changes related to mandibular forward growth in persons with Class II malocclusions. The longitudinal cephalometric films of 40 subjects with untreated Class II malocclusions from mean age 8.8 to 17.8 years (before and after pubertal growth) were analyzed and compared with the Bolton norms. There was no statistically significant difference in mandibular growth between the Class II samples and the Bolton norms upon cross-sectional comparison. In the Class II subjects, forward growth of the mandible was greater than that of the maxilla by 4.36 mm on average; the dentoalveolar complex moved forward relative to the maxillary basal bone (point A) 2.16 mm and moved backward relative to the mandibular basal bone (pogonion) 2.28 mm; a strong linear relationship (almost a 1:1 ratio) existed between mandibular forward growth and dentoalveolar complex movement (r = 0.881; y = 0.976 x + 0.183). Results indicated that the effect of forward growth of the mandible, which could potentially bring the lower dentition forward, vanished into the adaptation movements of the dentoalveolar complex through intercuspal locking. Disarticulating the occlusion to minimize the effects of the adaptive mechanism and taking advantage of normal mandibular forward growth could be fundamental biological bases in treating Class II malocclusions in growing patients.     

An evaluation of growth and stability in untreated and treated subjects

This retrospective longitudinal study compared skeletal and dental changes in orthodontically treated patients with changes in a comparable untreated group to evaluate the relationship between skeletal changes and mandibular incisor crowding. Cephalograms and models of 44 untreated subjects from the Broadbent-Bolton Growth Study and 43 treated patients were evaluated at "posttreatment" (14.3 +/- 1.5 and 15.2 +/- 1.1 years, respectively) and at "postretention" (23.2 +/- 3.4 and 28.9 +/- 3.6 years, respectively). Cranial base and mandibular superimpositions were used to measure cephalometric changes. Tooth-size-arch-length discrepancy, contact irregularity, and space irregularity were measured. In both groups, growth in the vertical dimension was twice that in the horizontal dimension. The untreated subjects, who were younger, exhibited greater yearly vertical growth increments than did the treated subjects. The treated subjects exhibited greater overjet and overbite increases than did the untreated subjects. Yearly changes in tooth-size-arch-length discrepancy were greater in the untreated than in the treated subjects, but there were no differences in the changes in irregularity between the 2 groups. A multivariate regression model, relating posterior facial height (Ar-Go) increase and lower incisor eruption to change in space irregularity, explained 42% of the variation in the untreated group (r = 0.64; P <.001). A weaker relationship was found in the treated group. Overjet change was negatively correlated with tooth-size-arch-length discrepancy. Changes in lower incisor crowding were related to growth in the vertical dimension and lower incisor eruption in both untreated (r = 0.64) and treated (r = 0.51) subjects.     

Finite-element morphometry of soft tissue morphology in subjects with untreated Class III malocclusions.

Soft tissue dynamics may contribute to maxillomandibular allometry (size-related changes in shape) associated with the development of Class III malocclusions. Lateral cephalographs of 124 prepubertal European American children were traced and 12 soft tissue landmarks were digitized. Resultant geometries were normalized, and Procrustes analysis established the statistical difference (p<0.001) between mean Class III and Class I configurations. Comparing the Class III configurations with normals for size-change, color-coded finite element analysis revealed a superoinferior gradient of positive allometry of the Class III facial nodal mesh. A conspicuous area of negative allometry (approximately 40%) was localized near soft subspinale, with a approximately 70% increase in size in the mental region. For shape-change, the Class III facial mesh was isotropic, except in the anisotropic circumoral regions. Conventional cephalometry revealed that about 50% of linear and 75% of angular parameters differed statistically (p<0.001). Soft tissue dynamics during early postnatal development may contribute to the development of Class III malocclusions.     

Craniofacial growth in untreated skeletal Class II subjects: A longitudinal study

Eighty-five (45 male and 40 female) skeletal Class II untreated subjects with low (< 27 degrees ), average (27 degrees - 36 degrees ), and high (> 36 degrees ) mandibular plane angles (MP-SN) were selected from the Bolton-Brush and the Burlington Growth Studies. Cephalograms of each subject at ages 9 and 18 were traced, and 28 parameters were measured. The difference in each parameter from ages 9 to 18 was calculated, and comparisons were made between the groups with low, average, and high angles. Results showed that for children at age 9, the high-angle group showed greater convexity, larger Y-axis and gonial angles, and greater anterior facial height, and the low-angle group had larger SNA and SNB angles, and greater posterior cranial base, mandibular body, ramus height, and posterior facial height. From ages 9 to 18, all the low-, average-, and high-angle groups showed a decrease of convexity (more flattened face) and a mandibular forward rotation (decreased MP-SN). The low-angle group displayed significantly more facial flattening and more mandibular forward rotation than did the high-angle group. Moreover, the mandibular incisors became more retroclined in the low-angle group and more proclined in the high-angle group with age. Comparisons between males and females showed similar skeletal growth patterns in angular measurements. However, a significant sex difference was noted in some linear measurements.