6453名17～21岁青年人恒牙发育异常的调查

目的调查青年人恒牙牙齿形态和数目异常的状况。方法2002至2004年对3所北京高校6453名17～21岁学生进行恒牙数目和形态异常的调查。对不同性别和不同牙位发育异常的患病率进行卡方检验，并对2种牙齿异常伴发的情况进行卡方检验。结果牙齿数目和形态异常的总患病率为16．07％。女性锥形牙或桶状牙、畸形中央尖和先天缺牙的患病率高于男性，差异有统计学意义（P〈0．05）。牙内陷、锥形牙或桶状牙好发于上颌侧切牙，畸形中央尖好发于下颌第二前磨牙，融合牙和先天缺牙好发于下颌切牙，差异均有统计学意义（P〈0．01）。锥形牙或桶状牙与先天缺牙伴发的比率高，差异有统计学意义（P〈0．01）。结论各种牙齿数目和形态异常的患病率、性别差异和好发牙位与以往的研究基本相符。但锥形牙或桶状牙、畸形中央尖的女性患病率均高于男性。     

The use of the Oral Health Impact Profile to measure the impact of mild,moderate and severe hypodontia on oral health‐related quality of life in young adults

There is limited understanding of the subjective impact of congenital absence of teeth in patients with hypodontia. This study aimed to investigate the impact of mild, moderate and severe hypodontia on oral health‐related quality of life (OHRQoL) and its relationship to age, gender and extent of hypodontia prior to treatment. 82 patients (43 females and 39 males, age range from 16 to 34 years) with a confirmed diagnosis of non‐syndromic hypodontia were recruited for this study prior to treatment. Demographic details were recorded and a clinical examination documented the number and location of missing teeth. Participants were also asked to complete an oral health‐related quality of life measure, the OHIP‐49. The impact was of hypodontia was significant, with appearance concerns being the most prevalent impacts on oral health‐related quality of life. Gender was a significant predictor of the overall OHIP‐49 score, with females having higher level of impacts. The number and location of missing permanent teeth was not a good predictor of quality of life. However, location of missing teeth was a predictor of the psychological discomfort subscale score. There was a positive correlation between age and the functional limitation and physical disability subscale scores. This study shows that the impact of hypodontia on oral health‐related quality of life is substantial.     

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.     

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.     

Tooth dimensions in hypodontia patients,their unaffected relatives and a control group measured by a new image analysis system

Tooth dimensions were compared between index patients with severe hypodontia (six or more congenitally missing teeth), their relatives with a full complement of teeth, and a control group. The groups consisted of 12 index cases (seven females and five males), 21 relatives without hypodontia (13 females and eight males), and a control group of 10 males and 10 females with complete dentitions, and no family history of hypodontia. All formed teeth were imaged buccally and occlusally from study models, with a digital camera linked to a computer. The images were acquired and measured using Adobe Photoshop and Image Pro Plus, respectively. Mesiodistal, buccolingual, or occlusogingival area and perimeter measurements were determined from each image. In the index hypodontia group tooth dimensions were significantly smaller (P < 0.001, Bonferroni corrected level) for maxillary and mandibular canines, and first premolars for all dimensions from the buccal view, and for maxillary and mandibular canines and first premolars, maxillary central incisors, maxillary first molars, mandibular lateral incisors, and mandibular second premolars for all dimensions from the occlusal view. In the relatives without hypodontia compared with the control group, mesiodistal dimensions from the buccal view were significantly smaller (P < 0.001) for the central incisors and maxillary first and second premolars, and for the maxillary and mandibular first premolars for all dimensions from the occlusal view. There was a trend for the tooth dimensions of all teeth in the index group to be smaller compared with the control group. The tooth dimensions of the relatives without hypodontia also tended to be smaller than the control group, but were larger than those of the index cases.     

800例正畸患者中先天缺失牙及其与多生牙、锥形牙相关性分析

目的：观察正畸患者中伴有恒牙先天缺失、多生牙和锥形牙或过小牙的发生率及分布,并分析其相关性。方法：随机抽取正畸患者800例,男260例,女540例,年龄12-40岁。通过石膏模型和曲面断层片统计先天缺牙、多生牙、锥形牙或过小牙的发生率及分布。通过分类变量的关联性来分析多生牙和锥形牙或过小牙与先天缺牙的相关性,假设检验采用列联表的独立性x2检验,并采用Pearson列联系数r来描述两变量关联程度。结果：800例中发生恒牙先天缺失100例,发生率为12．5％。常见的缺失牙位从多到少依次为下颌侧切牙、下颌第二前磨牙、下颌中切牙、上颌侧切牙、上颌第二前磨牙。多生牙的发生率为3．1％,锥形牙或过小牙占8．3％。通过分类变量的关联性分析得出,锥形牙或过小牙的发生与先天缺牙有相关性,Pearson列联系数r为0．173。结论：正畸患者中恒牙先天缺失的发生率为12．5％,最常见的缺失牙位是下颌侧切牙和下颌第二前磨牙;正畸患者中恒牙先天缺失和锥形牙或过小牙的发生具有相关性。     

Agenesis of the second premolar in males and females: distribution, number and sites affected

One of the most common anomalies of the dentition is congenitally absent second premolars and this form of hypodontia may occur as an isolated trait or in association with a syndrome. Using radiographs and clinical examinations, hypodontia of second premolars was assessed in 176 subjects (80 male and 96 female). Distribution of the hypodontia was assessed according to site and number missing in males and females. No significant differences were observed in males and females with respect to the number of premolars absent, sites affected or symmetry of the agenesis. Agenesis of a single second premolar was the most common form of this hypodontia with absence of three second premolars occurring least frequently.     

Dental anomalies in the primary dentition and their repetition in the permanent dentition: a diagnostic performance study

This study investigated the recurrence in the permanent dentition of dental anomalies of the primary dentition. A sample of 189 subjects (100 males, 89 females, mean age of 5 years and 7 months) with anomalies of primary teeth (tooth hypodontia, supernumerary teeth, geminated teeth, and fused teeth) was selected and re-analyzed at a mean age of 11 years and 2 months for the recurrence of the dental anomalies in the permanent dentition. As a control group, 271 subjects (123 males, 148 females) without dental anomalies in the primary dentition were selected. The recurrence in the permanent dentition of the dental anomalies in the primary dentition was evaluated by measures of diagnostic performance. The results showed high values for the repetition of hypodontia (positive likelihood ratio = 102.0); low score for the repetition of hyperdontia (positive likelihood ratio = 6.5); low positive likelihood ratio (9.1) for gemination of primary teeth resulting in supernumerary permanent teeth; high positive likelihood ratio (47.0) for fusion of primary teeth followed by missing permanent teeth. Dental anomalies in the primary dentition are associated with an increased likelihood of anomalies of the succedaneous permanent.     

先天缺牙与牙形态、大小异常相互关系的研究

目的 探讨先天缺牙与牙形态异常及牙大小异常的相互关系。方法 对79例先天缺牙患者的缺牙部位、缺牙数目，余留牙异常的牙体形态进行分析。并按缺牙程度及部位分成4组，测量其牙冠宽度。结果 （1）上颌侧切牙、下颌中切牙为临床最常见牙先天缺失部位，上颌中切牙，上下颌第一磨牙为牙列中最不易先天缺失的牙齿，但上颌中切牙在先天缺牙患者中常呈轻度的锥形牙冠。（2）先天缺牙常伴牙齿形态异常，以上颌侧切牙，下颌尖牙、上颌第二前磨牙，上下颌第二磨牙多见。（3）轻度先天缺牙患者余留牙大小无异常，随着先天缺牙严重程度增加，前牙有逐渐减小趋势而后牙大小较稳定。结论 （1）上颌侧切牙为牙列中最不稳定的牙齿：（2）牙齿形态、大小、数目异常可能是一个连续的变异过程，可能为同一机制的不同表现。     

Allergy as a possible predisposing factor for hypodontia

The aim of this retrospective study was to identify general health problems as potential predisposing factors for hypodontia in a population of Japanese orthodontic patients. The study included 3683 individuals (1312 males and 2371 females, 13-42 years of age; mean, 23 years 7 months). Dental pantomograms (DPTs) were used to diagnose hypodontia. Health histories were obtained through a questionnaire administered by the dentist in charge. The Mantel-Haenszel test was used to determine the significance of the differences in the prevalence of health problems. The overall frequency of hypodontia was 5.8 per cent. The average number of missing teeth per patient was 1.7. There was a high prevalence of systemic complications, which included allergy, asthma, atopy, and enlarged adenoids associated with hypodontia. Only allergy showed a significant relationship with hypodontia (P < 0.01). The environmental aetiology of hypodontia is not yet fully understood. However, based on the results of this retrospective study, predisposing general health problems, especially allergy, seem to be involved.     

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.     

48例外胚层发育不良综合征患者颌面骨形态分析

目的:了解外胚层发育不良综合征(ectodermal dysplasia,ED)患者的颌面部发育状况,为临床治疗提供参考.方法:收集2013年6月-2016年10月收治的48例ED患者的临床信息和头颅侧位X线片.将患者分为2组:第1组23例,除缺牙外,累及≥2种外胚层组织;第2组25例,除缺牙外,仅累及1种外胚层组织.比较2组病例的缺牙数及颌面骨形态影像学参数的差异.采用SPSS 17.0软件包对数据进行单样本t检验和成组t检验.结果:第1组缺牙数显著多于第2组(22.3±5.8∶12±6.6,P＜0.05).在女性患者中,第1组滞留乳牙数显著多于第2组(8±4∶2.4±2.7,P＜0.05).2组患者的上颌骨长度减少(ANS-Ptm减小)且位置后缩(S-Ptm、SNA、NA-PA减小),下颌骨前突(NP-FH增大)、颏部前突(Y轴角减小),下颌骨长度(Co-Po)及位置(S-Co)相对正常,骨性Ⅲ类错(牙合)(ANB＜0),全面高降低(N-Me减小).在男性患者中,第1组较第2组的SNA、NA-PA、ANS-Ptm、S-Ptm、Y轴角显著减小(P＜0.05),NP-FH显著增大(P＜0.05).结论:ED患者颌面骨形态表现为上颌骨长度减少及位置后缩,下颌骨长度和位置相对正常,下颌骨前突、颏部前突、骨性Ⅲ类错(牙合)和全面高降低.ED患者颌面骨形态异常的严重程度与缺失的恒牙数呈正相关,滞留的乳牙可能会促进颌面骨发育.     

散发性先天缺牙的临床特征分析

目的：探讨散发性先天缺牙的临床特征,分析其危害。方法：临床检查散发性先天缺牙病例,影像学观察,统计分析。结果：收集到11例散发性先天缺牙患者,男5例,女6例,患者缺牙1～25颗,伴有食物嵌塞（90.9%）、邻面龋及继发病变（81.8%）、创伤（72.7%）、牙周病（45.5%）、咬合异常（72.7%）。结论：散发性先天缺牙多为少数牙先天缺失,与性别无明显关系,伴有恒牙埋伏和乳牙滞留,缺牙部位具有随机性,先天缺牙影响口腔健康及咬合关系。     

Hypodontia in orthodontically treated children

The frequency of hypodontia in orthodontically treated children, both male and female, and the association between tooth type, the upper or lower arch, the affected side and Angle's classification were studied using interviews, oral, study cast and panoramic radiographic examinations of 212 patients with a mean age of 12 years 7 months. A hypodontia frequency of 11.3 per cent was found for the total sample. This was higher than the incidence of hypodontia reported in other studies of orthodontically treated children. The most frequently missing teeth were the maxillary lateral incisors, and maxillary and mandibular second premolars. The missing teeth were more often absent on the right (54.2 per cent) than on the left (45.8 per cent) side, in both males and females. One tooth was absent in 29.2 per cent of patients, two in 58.5 per cent, but seldom three or more. Orthodontic space closure was the treatment of choice in 87.5 per cent of the subjects.     

Missing lateral incisors in Iron Age South-East Asians as possible indicators of dental agenesis.

The absence of lateral incisors is generally a reflection of agenesis or hypodontia, with a significant genetic basis and possibly environmental influence on the phenotypic expression. A human skeletal sample from the Iron Age cemetery of Noen U-Loke in Thailand has a very high prevalence at 79% of adults (30/38) with at least one incisor missing in either maxilla or mandible. If the cause of this high rate is genetic, it may be indicative of homogeneity, and, therefore, endogamy and probably isolation, of the population represented. Supporting agenesis as the explanation for this is the lack of space between the central incisors and canines in more than half the cases. An alternative explanation is that the teeth may have been lost during life through pathology or deliberate removal (ablation). There is no evidence in the form of remodelled lesions for pathological loss of the teeth. Although there were no significant differences between males and females in the numbers of teeth missing, there were significant differences in the patterns of loss, with males having more missing teeth on the right and females more on the left. No evidence was found in the clinical literature of agenesis involving side preference by sex, so this may indicate deliberate removal of the teeth. Males were also more likely than females to have no space for the missing teeth. Ablation of teeth has been recorded in other prehistoric South-East Asian populations but in these cases the evidence was much clearer. Agenesis seems to offer the most likely explanation for the missing teeth at Noen U-Loke and if so, indicates that a small, isolated population may develop a very high rate of hypodontia, with a side preference dependent on sex.     

Oral health-related quality of life and severe hypodontia

The aims of the study were to assess oral health-related quality of life (ohqol) impact among patients with severe hypodontia and to determine the association between ohqol and the number of missing teeth. Twenty-five patients with severe hypodontia (four or more missing permanent teeth) self-completed the child perception questionnaire (CPQ) to assess oral symptoms (OS), functional limitation (FL), emotional well-being (EWB) and social well-being (SWB). Correlation between CPQ scores (overall and at domain level) and the number of missing teeth was assessed. All participants reported ohqol impact, 100% reported experiencing OS, 88% FL, 55% EWB and 100% SWB impacts. The correlation between the number of missing permanent teeth and the CPQ scores was moderate: overall CPQ score (r = 0.54), OS (r = 0.41), FL (0.52), EWB (0.52), SWB (0.49), P < 0.05. Having accounted for retained primary teeth (where a retained primary tooth was considered to have compensated for a missing permanent tooth), the correlation between the number of missing teeth and CPQ scores was strong: overall CPQ score (r = 0.94), OS (r = 0.78), FL (0.88), EWB (0.92), SWB (0.70), P < 0.001. Subjects with severe hypodontia report considerable ohqol impact. The number of missing permanent teeth was moderately correlated with ohqol. However, when retained primary teeth were taken into account, the number of missing teeth was highly correlated with ohqol. This study has implications in understanding the impact of hypodontia on quality of life and highlights the importance of retaining primary teeth in children and adolescents with severe hypodontia.     

邯郸市1895名大学生先天性缺牙的临床特征分析

目的了解河北邯郸市在校大学生恒牙先天性缺失的临床特征。方法随机对邯郸1895名大学生进行恒牙先天缺失临床特征的调查,并对先天缺牙患病率、数目及好发牙位等进行统计分析。结果恒牙先天缺失的总患病率为6.96%,男55例,女76例,性别间无统计学意义(P>0.05);下颌先天缺牙多于上颌(P<0.05);好发牙位为下颌中切牙;以缺1颗牙者最多见,占总人数的62.12%。患者缺牙伴有食物嵌塞者67.42%、邻面龋及继发病变者53.79%、牙合创伤者49.24%、牙周病者31.82%、咬合异常者61.36%。结论邯郸市在校大学生恒牙先天缺失多为少数缺牙,且性别间无统计学意义,下颌缺失牙数多于上颌,先天缺牙影响口腔健康及咬合关系。     

A survey of hypodontia in Japanese orthodontic patients.

INTRODUCTION: The purpose of this retrospective study was to assess the prevalence and distribution of hypodontia in the permanent dentition, excluding the third molars, in a sample of Japanese orthodontic patients. METHODS: Orthopantomograms of 3358 Japanese orthodontic patients (1453 boys and 1905 girls) between the ages of 5 and 15 years were examined for evidence of hypodontia. RESULTS: The prevalence of hypodontia was 8.5% (7.5% for boys, 9.3% for girls) with no statistically significant difference between the sexes. The average number of missing teeth per child was 2.4 (2.5 for boys, 2.4 for girls). Most (76.3%) children with hypodontia were missing either 1 or 2 teeth (77.1% for boys, 75.7% for girls). The prevalence of advanced hypodontia was 10.1% (11.0% for boys, 9.7% for girls). The most commonly missing teeth were the mandibular second premolars, followed by the mandibular and maxillary lateral incisors, and the maxillary second premolars; minor differences in the order of prevalence existed among groups of children classified by the number of missing teeth. Symmetrical hypodontia was predominant, and the most commonly symmetrical hypodontia was mandibular second premolar agenesis. No consistent finding was obtained as to which jaw had more missing teeth. The distribution of missing teeth was similar between the right and left sides of the dental arches in each group of children. Anterior tooth agenesis was predominant in children with minor hypodontia, and posterior tooth agenesis increased with hypodontia severity. CONCLUSIONS: The distinct characteristic of hypodontia in the Japanese population compared with other populations was a higher prevalence of both advanced hypodontia and mandibular lateral incisor agenesis in children with minor hypodontia.     

The pattern and prevalence of hypodontia in Koreans

Objective: The objective of this study was to evaluate the pattern and prevalence of hypodontia in the Korean population along with its association with the dental and skeletal polymorphisms. Subjects and materials: The diagnostic materials including casts, panoramic radiographs, and lateral cephalograms of 1622 Korean subjects (611 males, 1011 females) were used to evaluate the pattern and prevalence of hypodontia as well as its association with the congenital absence of the third molar. The changes in the tooth size and skeletal characteristics of the hypodontia group were evaluated using cast/cephalometric analysis and compared with the standard values of normal occlusion in Koreans. Results: The prevalence of hypodontia in Koreans was 11.2%. The mandibular lateral incisor and second premolar were the most frequently absent. Congenital absence of the third molar was observed more frequently in the hypodontia group than in the non‐hypodontia group. The prevalence of hypodontia in Class III malocclusion was significantly higher than in Class I or Class II malocclusion. Conclusion: The pattern and prevalence of hypodontia can vary in different ethnic groups. In Koreans, the special features of hypodontia were its association with a higher level of congenital missing third molars and skeletal Class III malocclusion.     

Symmetry and combinations of hypodontia in non-cleft and cleft palate children

Abstract — Symmetry and combinations of hypodontia was studied and compared in non-cleft (NONC) and cleft palate (CP) groups with different prevalences of hypodontia. The NONC group included 300 children with one or more congenitally absent permanent teeth, excluding the third molars, and 79 children with isolated cleft palate without accessory anomalies. There were no significant differences between the groups in distribution of children with agenesis of 1 to 11 teeth. Bilateral agenesis increased with increasing number of absent teeth per child, and it was more frequent in the maxillary teeth of the NONC group and in the mandibular teeth of the CP group. Concomitant agenesis was observed in one to four different dental fields per child, and the distribution of the subjects was similar in both groups. We conclude that the symmetry of agenesis may be dependent on the population frequency of hypodontia and on the number of absent teeth per child. The agenesis in the CP group may have a common genetic basis, but the substantially higher incidence of hypodontia in the maxilla is likely caused by factors similar to those causing the cleft itself.