正畸患者先天性牙缺失与错(牙合)畸形矢状骨型的关系

目的:统计正畸患者先天性牙缺失情况,探讨先天性牙齿缺失与错畸形骨型间的关系。方法:通过全景曲面断层片判定先天性牙齿缺失情况,通过头颅定位侧位片确定患者的矢状骨型,对先天性牙齿缺失部位与性别、骨型间的关系进行统计学分析。结果:上颌前牙段与上颌后牙段及下颌前牙段与上颌后牙段间缺牙数量比较有统计学意义(均为P<0.05),其他2组间缺牙数量均无统计学意义;女性先天性牙齿缺失数目高于男性,二者的差别具有统计学意义(P<0.05);Ⅱ类骨型错与下颌前牙段牙齿缺失相关,Ⅲ类骨型错与上颌前牙段牙齿缺失相关。结论:牙齿缺失部位与不同的错畸形骨型相关。     

An Analysis of the Skeletal Relationships in a Group of Young People with Hypodontia

Abstract

The objective of this investigation was to examine the dentofacial features of a group of patients with hypodontia, in particular assessing whether cephalometric analysis confirmed the clinical assumption of a reduced lower face height, and to determine the relationship of these facial features with different numbers of missing teeth. It took the form of a cephalometric study, undertaken in a dedicated Dental Hospital clinic for patients with hypodontia. The study group comprised 59 patients seen on the Hypodontia Clinic: 32 females, 27 males, mean age 13?1 ± 3?1 years (range 6–23 years). The average number of missing teeth was 7 (SD 5), ranging from 1 to 21. The mean SNA, SNB, and MMA angles were within normal limits, but there was a statistically significant reduction in the MMA when more than one tooth type was missing (P = 0?007) and the ANB angle decreased as the number of missing tooth types increased (P = 0?034). The mean values for the whole sample were within the normal range and did not demonstrate any feature specific to the group, but patients with more severe hypodontia showed tendencies to a Class III skeletal relationship and a reduced maxillary-mandibular planes angle.     

青少年牙发育不全患者颅面结构的初步研究

目的探讨牙发育不全患者的颅面结构,为临床诊治提供参考。方法选择英国牙发育不全患者病历59份纳入研究组,根据缺牙类型和缺牙数将研究组分为轻度、中度、重度、极重度共4个亚组,其中男27例,女32例,平均年龄（13.1±3.1）岁。以Woodworth等报道的正常资料为对照组。对所有研究对象进行X线头影测量对比分析。结果研究组与对照组的SNA、SNB、MMA差异无统计学意义,且均在正常值范围内。同T3组相比,T4组的SNB增大（t=-2.76,P=0.015）、MMA减小（t=-3.03,P=0.007）、ANB减小（t=-2.26,P=0.034）,三者差异均有统计学意义;59例牙发育不全患者中Ⅲ类颅面结构患者居多。结论牙发育不全患者的平均头影测量值在正常值范围内,59例牙发育不全患者中Ⅲ类颅面结构患者居多、上下颌平面角减小。     

不同类型磨牙症患者的颅颌面形态特征研究

目的测量分析不同类型磨牙症患者的头颅定位侧位片，对比研究各类磨牙症的颅颌面形态学特征。方法拍摄86个磨牙症患者的标准头颅定位侧位片，运用CASSOSX线片头影测量分析系统．选取Jarabak Analysis,Tweed Analysis 及Tideman Analysis中的37个相关指标，采用Bonferroni多重比较法分析不同类型磨牙症患者的颅颌面形态特征。结果（1）非正中型磨牙症患者的下颌角、后角总和、下颌下角、下颌平面与前颅底平面构成的角、殆平面与下颌平面构成的角、下颌平面与眶耳平面所构成的角等均大于正中型磨牙症（P〈0．01）；而后面高与前面高之比、前牙覆黯小于正中型磨牙症（P〈0．01）。（2）非正中磨牙症患者的下颌角和下颌下角大于混合型磨牙症（P〈0．001）；而上齿槽座点、鼻根点及下齿槽座点所构成的角（ANB）小于混合型磨牙症（P〈0．05）。结论（1）不同类型磨牙症患者的颅颌面形态各有特征。（2）非正中型磨牙症患者下颌向后旋转呈垂直向生长、有高角骨面型倾向。（3）正中型磨牙症患者下颌向前旋转呈水平向生长，为低角骨面型。（4）混合型磨牙症患者下颌有水平向生长及下颌后缩趋势。     

A radiographic study of tooth development in hypodontia

OBJECTIVE: To investigate the radiographic development of permanent teeth in a group of children (66 females and 69 males, aged 3.08-15.02 years) with agenesis of one or more permanent teeth compared to a matched group. DESIGN: Tooth formation of all developing permanent teeth was assessed using Haavikko's method (1970) from dental panoramic tomographs. The difference between dental and chronological age was tested using a paired t-test. The correlation between the difference of dental and chronological age and severity of hypodontia was investigated using Spearman correlation test. In addition, radiographs of all children with only one single missing tooth in one quadrant and no more than two agenesis in total (N=59), were analyzed using the non-parametric Wilcoxon sign test, in order to investigate if the development of the teeth adjacent to the site of the agenesis was effected. RESULTS: Tooth formation in children with hypodontia was significantly delayed compared to the matched group (p<0.001). The mean difference was 1.51 years (S.D. 1.37 years). The severity of the hypodontia effected the magnitude of the delay (p<0.01). The teeth adjacent to the site of the agenesis were significantly delayed compared to the corresponding teeth in the matched group (p<0.01). CONCLUSION: These results confirm that the development of permanent teeth in children with hypodontia is different when compared with a matched group.     

前方牵引对早期前牙反(牙合)患者软组织侧貌的影响

目的:探讨前方牵引矫治对早期前牙反软组织侧貌的影响。方法:选择前牙反伴有颜面形态异常(审美线明显异常)的儿童60人,男27人,女33人,年龄范围8～11岁,平均年龄9.3岁,将样本随机分为对照组和前方牵引治疗组,观察及治疗周期为11～13个月,平均12.1个月。治疗前后分别拍摄头颅侧位X线片,进行头影测量分析,统计学分析采用配对t检验。结果:治疗组矫治后的面突角、全面突角、下唇基角及鼻唇角明显减小,上下唇基角明显增大,上唇突点到审美线距离明显改善,与对照组间的差异均呈高度显著性,而上唇基角及下唇突点到审美线的距离治疗前后无明显变化。结论:前方牵引矫治后面部软组织侧貌明显改善,凹面型变为直面型或者接近正常面型,鼻、上唇、下唇以及颏部四者间的关系趋于协调,唇部曲线变得平缓、协调。     

Forsus矫治器矫治生长发育高峰期后骨性下颌后缩患者的研究

目的 分析Forsus矫治器治疗生长发育高峰期后骨性下颌后缩患者的疗效以及矫治的稳定性.方法 依据纳入标准选定戴用Forsus矫治器患者7例,在治疗前、治疗后和随访时拍摄头颅侧位片（随访时距治疗结束17～32个月）.建立坐标系,测量反映牙齿、颌骨的位置和角度的各项指标.结果 Forsus矫治器产生了三维方向的力量.在矢状方向上,下颌骨平均伸长6.47 mm,上牙舌倾（切牙平均8.97°,磨牙平均3.51°）,下牙唇倾（切牙平均3.93°）向近中移动（磨牙平均3.61 mm）,其中,骨性改变占36.68％,牙性改变占63.32％;在垂直方向上,上、下颌骨顺时针旋转（下颌平面平均1.70°）,下颌磨牙伸长（平均3.06 mm）;而且,这些改变在整个观察期间（治疗后平均25个月）保持相对稳定,仅下切牙有伸长的趋势（平均0.59 mm）.结论 Forsus矫治器治疗骨性下颌后缩,产生了显著的牙性和骨性改变,且疗效保持相对稳定.     

高位口外牵引在青少年骨性II类错治疗中的作用

目的:探讨高位口外牵引在青少年骨性II类错牙合早期矫治中的作用,并评价其临床疗效。方法:选取11例生长发育期骨性安氏II类错牙合病例,采用高位口外牵引治疗,与7例未经治疗的生长发育期骨性II类错牙合进行对照。摄取X线头影侧位定位片,用Pancherz分析法评判治疗过程发生的骨性和牙性变化,以SPSS11.0软件进行独立样本t检验。结果:高位口外牵引可以限制上颌发育,SNA、A-Olp2项指标在治疗组与对照组间具有统计学差异(P<0.01)。上颌磨牙远中移动具有显著差异(P<0.01)。结论:高位口外牵引能够限制上颌发育,有利于下颌发育,达到矫治目的;同时,垂直方向和矢状方向的牙及牙槽反应,有利于患者牙颌面形态的进一步改善。     

Nasoalveolar molding and skeletal development in patients with bilateral cleft lip and palate: A retrospective cephalometric study at the completion of growth

The aim of this retrospective long-term study was to assess the influence of primary columella lengthening and presurgical nasoalveolar molding (NAM) on the skeletal development at the completion of growth in patients with bilateral cleft lip and palate (BCLP).Lateral cephalometric radiographs at the completion of growth of consecutively treated patients BCLP patients, operated by the same surgeon, who had undergone NAM were compared with a second group of BCLP patients who were not treated with NAM. The groups were matched for sex and age. Independent samples t tests were carried out.23 Lateral cephalometric radiographs of BCLP patients (mean age 18.2 ± 1.3 years) who had undergone NAM were compared with a second group of 23 BCLP patients (mean age 18.4 ± 1.3 years) who were not treated with NAM. The only two significant differences were observed in Ans-Me/N–Me (control group = 0.6 ± 0.02; sample group = 0.57 ± 0.05; p = 0.019) and ILs^AnsPns (control group = 105.5 ± 7.9; sample group = 112.4 ± 8.6; p = 0.007). No other significant differences were observed in terms of facial skeletal development between the two groups.Presurgical NAM performed during infancy in BCLP patients does not seem to have negative effects on the skeletal development at the completion of craniofacial growth compared to the group of patients treated without NAM.     

Epidemiology and genetics of hypodontia and microdontia: A study of twin families

Objective:To identify genetic and environmental factors contributing to hypodontia and microdontia by using Korean twin family data.Materials and Methods:A total of 1267 individuals (525 men and 742 women; 180 monozygotic twins [MZ] and 43 dizygotic twins [DZ] from 282 families) underwent an oral examination as part of the Healthy Twin Study in Korea. Dental anomalies classified as hypodontia or microdontia were diagnosed using radiographs and clinical examinations. In order to estimate genetic contributions to dental anomalies, we estimated the pairwise concordance rate (PCR), recurrence risk ratio (RRR), and heritability (h2).Results:The prevalence of hypodontia and microdontia was 3.55% and 3.00%, respectively. MZ had the highest PCR and RRR (13.0–15.3). The PCR and RRR values for both anomalies were much higher for DZ (5.0–11.9) than for siblings (1.4–2.6), despite the fact that DZ pairs and sibling pairs share 50% genetic identity. Further genetic analysis revealed both an additive genetic effect (0.38 when hypodontia and microdontia were pooled) and a strong “twin effect” (0.52 when hypodontia and microdontia were pooled).Conclusions:This twin-based study revealed that the formation of dental anomalies is affected by both genetic and environmental factors, and that the impact of these factors varies according to the specific dental anomaly.     

Rehabilitation of ectodermal dysplasia patients presenting with hypodontia: outcomes of implant rehabilitation part 1

Purpose

This study has evaluated the pre and post perceptions of patients with ectodermal dysplasia (ED) who have been referred to Westmead Centre for Oral Health for treatment with dental implants.

Impact of resin bonded bridgework on quality of life of patients with hypodontia

ObjectivesTo determine the impact of hypodontia on the quality of life of adolescent and young adult patients, and, to assess the impact of restoring tooth spaces with resin bonded bridgework on quality of life of patients with hypodontia.MethodsIn a prospective study, 82 patients with a confirmed diagnosis of hypodontia participated. The primary outcome was oral health related quality of life (OHRQoL) and this was measured using the OHIP-49 prior to treatment. The pre-treatment sample was then divided into two groups: the test group (n = 40 patients) who had completed orthodontic treatment and had tooth spaces restored with resin bonded bridgework, and, a control group (n = 42 patients) who were still in the process of orthodontic treatment. All patients completed a follow-up OHIP-49, and between and within group comparisons made.ResultsThe pre-treatment sample included 43 females and 39 males, age ranged from 16 to 34 years (median age 19). Forty-three patients had more than 4 congenitally missing teeth and thirty-nine had ≤4 congenitally missing teeth. There were no differences between the groups prior to treatment. For the test group, there was a significant improvement in median OHIP summary scores (p < 0.001) after treatment. OHIP scores deteriorated to a significant degree for control subjects (p = 0.002). The effect sizes for the pre–post treatment change in both groups were moderate to large.ConclusionsHypodontia has a significant impact on oral health related quality of life. Provision of resin bonded bridges has a positive impact on oral health related quality of life of patients with hypodontia.     

A multidisciplinary approach for the management of hypodontia: case report

Hypodontia is the congenital absence of one or more teeth and may affect permanent teeth. Several options are indicated to treat hypodontia, including the maintenance of primary teeth or space redistribution for restorative treatment with partial adhesive bridges, tooth transplantation, and implants. However, a multidisciplinary approach is the most important requirement for the ideal treatment of hypodontia. This paper describes a multidisciplinary treatment plan for congenitally missing permanent mandibular second premolars involving orthodontics, implantology and prosthodontic specialties.     

Reproducibility of maxillofacial landmark identification on three-dimensional cone-beam computed tomography images of patients with mandibular prognathism: Comparative study of a tentative method and traditional cephalometric analysis

Objective:To clarify the reproducibility of a tentative method for identifying maxillofacial landmarks on three-dimensional (3D) images obtained with cone-beam computed tomography (CBCT) for dental use in patients with mandibular prognathism. Also, the influence of level of experience of dentists applying the method was investigated by dividing them into two groups according to experience.Materials and Methods:Dentists with less (group A) or more (group B) than 3 years of experience of cephalometry and 3D image manipulation analyzed CBCT data from 10 patients using two different landmark identification methods: method 1 used conventional cephalometric definitions and method 2 used detailed landmark identification definitions developed for each cross-sectional plane. The plotting of nine landmarks was performed twice, and 10 coordinate values were obtained for each landmark. To assess reproducibility, the 95% confidence ellipse method was used.Results:Comparative analysis showed that method 2 was highly reproducible. Group B subjects attained smaller ellipsoid volumes than group A subjects, regardless of the landmark identification method used. With method 1, except for condyle and coronoid process, all landmarks showed a higher level of reproducibility in group A subjects than in group B subjects. With method 2, however, five landmarks showed no differences between the methods.Conclusion:The method proposed here may be highly reproducible regardless of the evaluators'' experience.     

佳木斯地区朝鲜族正常青少年McNamara分析

目的建立佳木斯地区朝鲜族正常青少年McNamara分析法的正常值。方法选取佳木斯地区朝鲜族正常青少年65名,拍摄正中位X线头颅侧位定位片,进行X线头影测量McNamara分析,并与哈尔滨地区同年龄组汉族人和白种人McNamara分析法的正常值进行比较。结果佳木斯地区朝鲜族正常青少年男女部分测量值存在显著性差异;与哈尔滨地区同年龄组汉族及白种人McNamara分析法正常值比较,部分测量值也存在显著性差异。结论恒牙初期McNamara分析法测量值存在性别差异和民族特征。佳木斯地区朝鲜族正常青少年McNamara分析法的正常值可为矫治本地区朝鲜族青少年错畸形提供临床参考。     

上海地区男性少年儿童颈椎骨骨龄的测量分析

目的建立并探讨上海地区男性少年儿童颈椎骨龄的测量方法。方法随机选择上海地区240名8-15岁男性少年儿童X线头颅侧位定位片,参考Mito的颈椎骨龄测量计算法并加以改进,对第三、四颈椎体进行测量分析,应用多元逐步回归分析得出颈椎骨龄计算方法。结果第三、四颈椎体各测量项目随年龄的增长呈现规律性变化,建立颈椎骨龄计算回归方程为Y=-4．968＋4．250AH4／AP4＋10．041AH3／H3＋6．184Ha／AP3（r=O．882）。结论应用本研究建立的方法计算出的颈椎骨龄可作为上海地区男性少年儿童颌面部生长发育的评价指标,为正畸临床提供参考。     

不同体位下无鼾者与OSAHS患者的头影测量比较

目的:借助X线头影测量分析,探讨3种不同体位下,无鼾者和阻塞性睡眠呼吸暂停低通气综合征(Obstructivesleepapneahypopneasyndrome,OSAHS)患者的颅面结构及气道周围软硬组织的关系。方法:10例无鼾者和10例OSAHS患者在3种不同体位下,分别拍摄常规坐位头影测量侧位片及仰卧位、放松位头颅侧位片,并进行头颅测量分析。结果:同一体位下,与无鼾者相比,OSAHS患者的ANB角、软腭厚度及舌骨前上点至下颌平面垂直距离增加,口咽距(U-Pu)减小;仰卧位和放松位时,无鼾者的SNB角、MP-SN角均比坐位时减小,SPT增加;H-C3距、PAS距减小;OSAHS患者H-C3距比坐位时也减小。结论:3种不同体位下,无鼾者与OSAHS患者在颅面结构及气道周围软硬组织结构关系方面的差异具有显著性。     

早期骨性安氏Ⅲ类错[牙合]畸形治疗预后预测的临床研究

目的：探讨早期骨性安氏Ⅲ类错[牙合]患者早期治疗的预后预测指标,为临床筛选手术治疗和非手术治疗提供依据。方法：100例成人及青少年分成5组,正常[牙合]成人组20例,正常[牙合]青少年组20例,骨性安氏Ⅲ类错[牙合]成人组28例,早期骨性安氏Ⅲ类错[牙合]治疗组24例,早期骨性安氏Ⅲ类错[牙合]治疗失败组8例。在头颅侧位定位片上测量腭平面角、面角、AB平面角、APDI值、ODI值、KIX值。采用SAS6.12软件包进行统计学分析。结果：正常人KIX的平均值在1.2以下。早期治疗组患者治疗前KIX值均值为1.51,治疗后KIX值均值减小为1.36。早期治疗失败的患者KIX值均值为1.81,治疗后为1.83。各组间比较均有高度显著性差异,P〈0.001。结论：手术和非手术治疗的KIX指标临界值为1.5,可作为早期治疗和延期治疗的初步筛选的指标之一。     

An analysis of the skeletal relationships in a group of young people with hypodontia

The objective of this investigation was to examine the dentofacial features of a group of patients with hypodontia, in particular assessing whether cephalometric analysis confirmed the clinical assumption of a reduced lower face height, and to determine the relationship of these facial features with different numbers of missing teeth. It took the form of a cephalometric study, undertaken in a dedicated Dental Hospital clinic for patients with hypodontia. The study group comprised 59 patients seen on the Hypodontia Clinic: 32 females, 27 males, mean age 13.1+/-3.1 years (range 6-23 years). The average number of missing teeth was 7 (SD 5), ranging from 1 to 21. The mean SNA, SNB, and MMA angles were within normal limits, but there was a statistically significant reduction in the MMA when more than one tooth type was missing (P = 0.007) and the ANB angle decreased as the number of missing tooth types increased (P = 0.034). The mean values for the whole sample were within the normal range and did not demonstrate any feature specific to the group, but patients with more severe hypodontia showed tendencies to a Class III skeletal relationship and a reduced maxillary-mandibular planes angle.     

The reliability and reproducibility of an Android cephalometric smartphone application in comparison with the conventional method

ObjectivesTo assess the reliability and reproducibility of linear and angular measurements of the cephalometric smartphone Android application OneCeph in comparison with the conventional method.Materials and MethodsA total number of 22 landmarks were registered, and 26 skeletal and dental cephalometric parameters were measured on 30 pretreatment cephalograms. The measurements for both digital (OneCeph) and conventional tracings were performed twice with a 4-week interval. The reliability (intraexaminer error) was evaluated by using the Pearson correlation coefficient. The variation in measurements between the tracing techniques (reproducibility) was determined by paired t-test.ResultsThe Pearson correlation coefficients of all cephalometric measurements for each tracing technique were ≥ 0.95. Significant differences between the two tracing techniques were detected in five measurements (SNB angle, N I to Pog linear measurement, U1-Apoint linear measurement, U lip to S line, and nasiolabial angle; P < .05).ConclusionsUsing 26 measurements to compare both tracing methods, all mean differences between the digital (OneCeph) and conventional methods were below 1 degree/1 mm, indicating that differences between the tracing methods were clinically insignificant. The U1-A point measurement was an exception for the digital method (OneCeph) with a clinically significant difference of 1.25 mm (P < .01); the difference was a result of wrongly measuring the distance from the A line to the incisor edge of the upper central incisor rather than the facial surface of the upper incisor. This leads to the conclusion that both tracing methods were reliable for daily clinical practice.