Hypodontia in children with various types of clefts

The prevalence of hypodontia in children with clefts, both inside and outside the cleft region, and the possible association between the side of the cleft and the side of the missing teeth were studied using radiographs of 278 patients with cleft lip, cleft palate, or both (158 boys and 120 girls), age 5 to 18 years (mean age 10.4 years). A hypodontia prevalence of 77% (excluding third molars) was found for the total cleft sample. This was significantly higher, both statistically and clinically, than the incidence of hypodontia reported for noncleft populations, and considerably higher than the prevalence reported in other studies of children with clefts. The maxillary permanent lateral incisors were the teeth most frequently missing on the cleft side (259 teeth) followed by the maxillary (47 teeth) and mandibular (23 teeth) second premolars, in both boys and girls. The teeth that were most often missing on the noncleft side were the maxillary second premolars (12 teeth), followed by the maxillary lateral incisors (10 teeth) and mandibular second premolars (6 teeth). Hypodontia of both the maxillary lateral incisors and second premolars was found more frequently on the left side, which also has a higher frequency of clefting.     

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.     

Hypodontia and hyperdontia of permanent teeth in Hong Kong schoolchildren

This study was performed to determine the prevalence of hypodontia and hyperdontia of permanent teeth amongst Southern Chinese children in Hong Kong. The sample consisted of 1093 12-yr-old children on whom a panoramic radiograph was taken. The prevalence of congenitally missing teeth (third molars excluded) was 6.1% in boys, 7.7% in girls, and 6.9% for both sexes combined. On the average, each child was missing 1.5 teeth. The most commonly absent tooth was the mandibular incisor, affecting 58.7% of the children with hypodontia. Thirty children (2.7%) had supernumerary teeth, with a male:female ratio of 6.5:1; in four cases the tooth had erupted. Three children had fourth molars and one case of a supplemental premolar was recorded (all unerupted). Four cases of a maxillary supernumerary tooth and hypodontia in the mandible were seen.     

Congenitally missing teeth in the Israeli cleft population.

OBJECTIVE: The purpose of the study was to determine the prevalence of congenitally missing teeth in a group of Israeli children with various types of clefts. DESIGN: Prevalence of congenitally missing teeth was determined for 179 children with cleft lip, cleft lip and alveolar ridge, cleft lip and palate, and cleft palate. Subgroupings were assessed according to patient sex, origin, cleft type, tooth type, and the side of hypodontia. The diagnosis of congenitally missing teeth (CMT) was based on initial and follow-up panoramic roentgenograms. In case of doubt, occlusal or periapical roentgenograms as well as clinical dental photographs were also used. SETTING: Data collection was conducted at the Rambam Medical Center, Orthodontic and Craniofacial Unit, Haifa, Israel. RESULTS: In the total cleft group, 67.6% of the patients presented with hypodontia, totaling 246 missing teeth. A statistically significant difference was found in the distribution of patients with CMT of Jewish and minority origin according to sex. Cleft lip and palate was the most frequently affected group in which 195 teeth were missing. The most frequently missing tooth among the cleft population was the maxillary incisor. The order of frequency of the other missing teeth was the same as in the normal population. Hypodontia and malformations of permanent teeth were most common on the cleft side. CONCLUSION: The frequency of CMT in the Israeli cleft population studied was higher than in the intact population. This confirms findings in other populations worldwide.     

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.     

Probability of congenitally missing teeth: Results in 1,191 children in the Burlington Growth Centre in Toronto

abstract The position and frequency of anodontia was determined from oblique and postero-anterior cephalograms of 1,191 children (615 males and 576 females) from the Burlington Growth Centre. These children ranged from age 6 to 12 years and some were studied cross-sectionally while others were studied serially. The presence or absence of congenitally missing teeth were recorded from cephalograms. Of all the children studied, only 7.4% had congenitally missing teeth. Most frequently, only one or two teeth were congenitally absent. Males, most commonly, had only one tooth missing whereas females had a greater chance of having two or more teeth absent. The most commonly absent tooth was the mandibular second premolar, then the maxillary lateral incisor followed by the maxillary second premolar. When a tooth was missing, there was a greater probability that other teeth would be missing.     

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

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.     

儿童口腔科门诊先天缺牙患者临床特征和发病因素研究

目的    研究儿童口腔科门诊先天缺牙患者的临床特征和可能影响发病的因素。方法    对2014年1—12月于中国医科大学附属口腔医院儿童口腔科就诊的16 320例患者进行先天缺牙的临床调查,针对先天缺牙的部位、数目及可能影响发病的因素等进行分析。结果    326例患者确诊为先天缺牙,占调查患者人数的2.0 %。其中,多数牙缺失患者44例,平均缺牙数为（7.98 ± 2.98）颗;个别牙缺失患者282例,平均缺牙数为（2.09 ± 1.04）颗。多数牙缺失患者中具有家族遗传史者所占比例明显高于个别牙缺失患者。缺牙好发部位依次为下颌第二前磨牙、上颌第二前磨牙、上颌侧切牙、下颌中切牙、第一前磨牙、上颌尖牙。采用非条件Logistic回归对先天缺牙的可能影响因素进行分析,发现家族史是先天缺牙的危险因素（P < 0.01）,而患者父母的文化程度、母亲受孕年龄、母亲妊娠期放射线接触史及是否为早产儿等因素,均不是先天缺牙的影响因素（P > 0.05）。结论    先天缺牙多为个别牙缺失,好发部位主要为下颌第二前磨牙;多数牙缺失可能与家族遗传密切相关。     

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??Objective    To investigate the clinical characteristics and possible related factors of tooth agenesis in the patients in the pediatric dentistry. Methods    A total of 16320 children?? who came to Pediatric Dentistry Clinic of Stomatology Hospital affiliated to China Medical University from January to December in 2014?? were examined. The number?? position and the influencing factors were analyzed. Results    Totally 326 children were diagnosed with tooth agenesis?? accounting for 2.0%. Among these patients?? 44 were oligodontia with the average number of missing teeth at 7.98 ± 2.98?? 282 were hypodontia with the average number of missing teeth at 2.09 ± 1.04. The proportion of children with family history in oligodontia was significantly higher than that in hypodontia. Most of the missing teeth were located in the second mandibular premolar?? followed by the second maxillary premolar?? maxillary lateral incisor?? mandibular central incisors?? the first molar and maxillary cuspid. Influencing factors for tooth agenesis were analyzed by non-conditional Logistic regression. Family history was a risk factor for congenital missing teeth ??P < 0.01??. Parents' educational level?? pregnancy age?? history of radiation exposure during pregnancy and preterm birth were not the influencing factors for tooth agenesis ??P > 0.05??. Conclusion    Hypodontia is the most common type of tooth agenesis and the second mandibular premolars are predominantly affected. Oligodontia might be closely relate to genetic factor.     

An orthopantomographic study of hypodontia in permanent teeth of Japanese pediatric patients

Hypodontia of permanent teeth was evaluated from orthopantomograms of 2072 apparently healthy pediatric patients at The Hospital of Nihon University School of Dentistry at Matsudo. The prevalence of congenitally missing teeth (CMT) was 8.7% in boys and 10.8% in girls, and 9.4% for both sexes combined. Most cases (67.8%) involved either one or two missing teeth. There were in total 574 CMT, and on average 2.8 teeth were missing per child. The most commonly absent tooth was the mandibular second premolar. On the other hand, no first molars were missing in any case. A high frequency of CMT mandibular incisors (18.82%) was observed, and this seems to be a characteristic peculiar to individuals of Asian ethnicity. Oligodontia (6 or more CMT excluding the third molar) ranged from 6 to 14 teeth, with a prevalence of 1.4% in general: 1.8% for girls and 0.9% for boys. Symmetry of CMT was predominant: 214 pairs for bilateral symmetry and 107 pairs for symmetry between two antagonistic quadrants. The distribution of CMT between maxillary and mandibular hypodontia in the right and left quadrants for boys and girls no had significant association (P < 0.05).     

Oral health of southern Chinese children and adolescents with severe hypodontia

OBJECTIVE: The aim of this study was to assess the oral health condition of southern Chinese children and adolescents with severe hypodontia. METHODS: This was a cross-sectional clinical study in the dental teaching hospital in Hong Kong. Twenty-five children and adolescents with severe hypodontia, and a comparison group of 25 age- and gender-matched controls took part. Verified clinical examination techniques were used to assess the pattern of missing teeth, tooth spacing, dental caries, periodontal condition, enamel defects, and tooth wear. Statistical comparisons were made between groups using independent Student t-tests and chi-square tests. RESULTS: The mean number of congenitally missing permanent teeth in the severe hypodontia group was 9.1 (SD = 5.0), with the maxillary lateral incisor being the most common missing tooth (14.5%). There were significant space discrepancies in both jaws between groups (P < 0.001). Caries prevalence was low with no difference between groups. There was no difference in periodontal condition between groups, with about half of the participants having no gingival inflammation. The severe hypodontia group had more enamel defects (P = 0.043), enamel hypoplasia (P = 0.044) and tooth wear (P = 0.005) than the comparison group. Three of the severe hypodontia group had ectodermal dysplasia. CONCLUSIONS: The oral health condition of southern Chinese children and adolescents with severe hypodontia was good in terms of caries experience and periodontal health. However, the increased prevalence of developmental defects of enamel and tooth wear complicates already complex interim and definitive prosthodontic management, and may increase psychosocial impact.     

Congenitally missing maxillary primary canines: report of three cases

BACKGROUND: Hypodontia is uncommon in the primary dentition and lateral incisors are the most commonly missing primary teeth in the patients affected. Studies have found that hypodontia in the primary dentition involving only maxillary canine is rare. CASE REPORTS: Three cases of hypodontia in the primary dentition involving only maxillary canine are presented. Two of them were affected by hypodontia and hyperdontia in the permanent dentitions respectively, yet all the permanent canines developed normally in these three cases. CONCLUSION: In children with congenitally missing maxillary canines, the permanent dentitions may show diverse anomalies in tooth numbers, ranging from hypodontia to hyperdontia.     

Hypodontia prevalence and pattern in women with epithelial ovarian cancer

Objective:To analyze the possible association between hypodontia and epithelial ovarian cancer (EOC), with the special interest in hypodontia pattern.Materials and Methods:One hundred twenty women with EOC treated at the Department of Gynecologic and Breast Oncology at the University Clinical Centre and 120 gynecologically healthy women of the same average age were reviewed for the presence and pattern of hypodontia. Collected data were analyzed for frequency, tooth type, location per jaw and side, number of missing teeth per person, and family history of hypodontia.Results:The results of the study showed prevalence of hypodontia in 19.2% of women with EOC and in 6.7% of women in the control group (P  =  .004). The most frequently missing teeth for women with EOC and women in the control group were maxillary second premolars and maxillary lateral incisors, respectively. Unilateral occurrence of hypodontia was more common than bilateral occurrence in women with EOC (P  =  .034). Of women with EOC and hypodontia, 21.7% reported a positive family history of hypodontia compared with no report in the control group of women with hypodontia (P  =  .150).Conclusions:The results statistically support possible association between EOC and hypodontia. Because hypdontia can be recognized early in life, this finding could possibly help in earlier detection of EOC, resulting in better prognosis and treatment in earlier stages of the disease. Earlier EOC diagnosis and treatment could save many lives.     

非综合征性单侧完全性唇腭裂恒牙发育异常的研究

目的 经回顾性研究了解非综合征性单侧完全性唇腭裂患者恒牙发育异常的情况.方法 收集244例植骨期非综合征性单侧完全性唇腭裂患者的影像学资料,记录和统计分析恒牙发育异常.结果 在本研究中各种恒牙异常的发生率为:先天缺失163例(269颗)(163/244,66.8%),最常累及的牙位是上颌侧切牙;畸形牙82例(85颗)(82/244,33.6%),绝大多数为上颌侧切牙的小牙畸形;额外牙12例(12颗)(12/244,4.9%),多发生于裂区,表现为畸形小牙.牙位发育异常的性别比较发现,非裂侧上颌仅侧切牙缺失,男性高于女性(P<0.05).裂侧的先天缺牙、额外牙和畸形牙的发生率均高于非裂侧,差异有统计学意义(P<0.01),上下颌均有相同发现.结论 非综合征性单侧完全性唇腭裂患者各类牙齿发育异常的患病率均高于健康人群.裂侧的牙齿发育异常较非裂侧更为多见.

Abstract：

Objective To investigate the prevalence of dentM anomalies in Chinese children with complete unilateral cleft lip and palate(UCLP).Methods Dental histories and radiographs of 244 Chinese children with UCLP were collected.The diagnosis of dental anomalies waft based on panoramic radiographs before alveolar bone grafting.All patients were over 8 years old.Results In the UCLP group,66.8% of the patients was presented with hypodontia.The maxillary lateral incisors were the most common teeth affected,followed by maxillary second premolars,mandibular incisors and mandibulax second premolars.A total of 33.6%the patients Was presented with dental malformation,most were mierodontic laterel incisors.A total of 4.9% the patients was presented with hyperdontim The supernumerary teeth were more frequently found in the cleft region.The prevalence of missing maxillary lateral incisor in the noneleft side was statistically different between genders,which was higher in male(P<0.050).This group of Chinese children with UCLP demonstrated significantly higher prevalence of hypodontia,hyperdontia,and malformation on the cleft side than on the noncleft side(P<0.01).Conclusions Hypodontia is the most common type of dental anomalies.The prevalence of dental anomalies is higher in the UCLP patients than in the normal population.Dental anomalies occur more frequently on the cleft side than on the nonclefi side.     

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.     

A cephalometric study to investigate the skeletal relationships in patients with increasing severity of hypodontia

Objectives:To determine the skeletal relationships in patients with hypodontia and analyze the effects of severity and pattern.Materials and Methods:Pretreatment lateral cephalograms from 277 patients with hypodontia, categorized by the number of missing teeth as mild (1–2), moderate (3–5), or severe (≥6), were digitized recording angular measurements and ratios and compared with published norms matched for age and gender. Pattern was determined as mandibular, maxillary, bimaxillary, bilateral, anterior, posterior, and anteroposterior. Linear regression models assessed relationships between number of missing teeth and cephalometric parameters, controlling for the pattern of hypodontia.Results:For every additional missing tooth, SNA, SNB, and ANB decreased 0.3°, 0.1°, and 0.2°, respectively; this was clinically significant for >4, >10, and >5 missing teeth, respectively. Mandibular to cranial base ratio decreased 0.3% for every additional missing tooth; this was clinically significant for >10 missing teeth. The MMPA decreased 0.3° for every additional missing tooth; this was clinically significant for >7 missing teeth. Percentage LAFH decreased 0.2% for every additional missing tooth; this was significant for >7 missing teeth. Jarabak ratio increased 0.2% for each additional missing tooth; this was clinically significant for >10 missing teeth. Anterior hypodontia significantly decreased most cephalometric parameters.Conclusions:Patients with hypodontia demonstrated a tendency toward a Class III relationship, caused by decreased maxillary and mandibular angular prognathism and MnCB ratio, though the effect was greater on the maxilla than the mandible. Clinical significance was only associated with severe hypodontia. Vertically, there was a tendency toward decreased MMPA and %LAFH; this was clinically relevant only with severe hypodontia. Anterior hypodontia had a significant effect on skeletal relationship.     

Prevalence and distribution by tooth type and surface of developmental defects of dental enamel in a group of 15- to 16-year-old children in South Wales

In 1984 the prevalence and distribution of developmental defects of dental enamel in 791 children aged 15-16 years was determined using the DDE index. The children were all residents of the county of South Glamorgan, Wales, which has a public water supply containing less than 0.1 mg fluoride/litre. The teeth were dried but not cleaned prior to examination and a dental operating light was used for illumination. Teeth with some type of defective enamel were seen in 50.1 per cent of children. White/single opacities were present in 28.3 per cent of children and white/diffuse, patchy opacities in 10.2 per cent of children. The enamel was abnormal in 5.71 per cent of all teeth with white/single opacities and white/diffuse, patchy opacities occurring in 1.81 per cent and 1.66 per cent of teeth respectively. There were no significant differences between boys and girls in terms of mouth or tooth prevalence of defects. Overall, 7.6 per cent of maxillary teeth were affected compared to 4.3 per cent of mandibular teeth. Most teeth were affected equally on right and left sides of the mouth except for maxillary lateral incisors and canines which had significantly more defects on the right (P less than 0.05 and P less than 0.005 respectively) and maxillary second molars, which had significantly more defects on the left (P less than 0.01). Maxillary central incisors (15.2 per cent) were affected by enamel defects most often followed by maxillary first molars (9.1 per cent) and maxillary lateral incisors and mandibular first molars (both 8.3 per cent).(ABSTRACT TRUNCATED AT 250 WORDS)     

Hypodontia of permanent teeth in Danish schoolchildren

Hypodontia, congenitally missing teeth, is one of the conditions recorded during systematic orthodontic screening of groups of children attending a community child dental health service. The present investigation reports the prevalence of hypodontia in 3325 9–10-year-old children in the 3rd schoolgrade examined with an orthopantornographic radiograph. The prevalence of children with hypodontia was found to be 7.8%. Fifty percent of these children were missing only one tooth while 85% were missing either one or two teeth. More teeth were missing in the mandible than in the maxilla. The teeth most frequently missing were the second premolars, representing 67% of the congenitally missing teeth. Symmetrical hypodontia of second premolars occurred approximately twice as often in girls as in boys. Though more teeth were congenitally missing in girls than in boys, no difference could be seen in the prevalence of hypodontia in boys (7.7%) and girls (7.8%).     

Prevalence of malocclusion and orthodontic treatment need in children and adolescents in Bogota, Colombia. An epidemiological study related to different stages of dental development

The aim of the study was to assess the prevalence of malocclusion in a population of Bogotanian children and adolescents in terms of different degrees of severity in relation to sex and specific stages of dental development, in order to evaluate the need for orthodontic treatment in this part of Colombia. A sample of 4724 children (5-17 years of age) was randomly selected from a population that attended the Dental Health Service; none had been orthodontically treated. Based on their dental stages the subjects were grouped into deciduous, early mixed, late mixed and permanent dentition. The registrations were performed according to a method by Bj?rk et al. (1964). The need for orthodontic treatment was evaluated according to an index used by the Swedish National Board of Health. The results showed that 88 per cent of the subjects had some type of anomaly, from mild to severe, half of them recorded as occlusal anomalies, one-third as space discrepancies, and one-fifth as dental anomalies. No clear sex differences were noted, except for maxillary overjet, spacing, tooth size (all more frequent in boys), and crowding (more frequent in girls). Occlusal anomalies and space discrepancies varied in the different dental developmental periods, as did tipped and rotated teeth. Little need for orthodontic treatment was found in 35 per cent and moderate need in 30 per cent. A great need was estimated in 20 per cent, comprising children with prenormal occlusion, maxillary overjet, or overbite (> 6 mm), posterior unilateral crossbite with midline deviation (> 2 mm), severe crowding or spacing, congenitally missing maxillary incisors, impacted maxillary canines or anterior open bite (> 3 mm in the permanent dentition). Urgent need for treatment was estimated to be 3 per cent, comprising subjects with extreme post- and pre-normal occlusion, impacted maxillary incisors or extensive aplasia.     

Dental transposition as a disorder of genetic origin

A sample of 85 dental transpositions in 75 subjects (27 male, 48 female; mean age at diagnosis 12.25 years) involving both maxillary and mandibular arches was analysed using dental panoramic radiographs and clinical records. Transposition affected the maxillary dentition (76 per cent) more frequently than the mandibular dentition (24 per cent). Unilateral transposition accounted for 88 per cent of cases, with the maxilla being involved more commonly than the mandible. Overall, the most common transposition involved the maxillary canine and first premolar (58 per cent). Considering the jaws in isolation, the canine and first premolar were the most commonly affected teeth in the maxilla (83 per cent) whilst in the mandible, the canine and lateral incisor teeth were most commonly transposed (73 per cent). No significant difference in symmetrical distribution of the unilateral transposition sample occurred. There was evidence of associated hypodontia in 41 per cent of the sample; however, if third molars were excluded, this figure decreased to 25 per cent. Peg-shaped maxillary lateral incisors were judged to be present in 27 per cent of subjects, whilst 41 per cent had retained primary teeth; all of these, except one, were primary canines. Overall, the majority of the sample (76 per cent) demonstrated at least one of the dental anomalies under investigation. Multivariate analysis showed associations between unilateral transposition, gender, and the presence of peg-shaped maxillary lateral incisors; whilst bilateral transposition was more closely associated with gender and the presence of retained primary teeth. There was a poor association between both unilateral and bilateral transposition and hypodontia. Together, these results suggest a mutifactorial aetiology to this disorder, with both genetic and environmental factors playing an important role.