Aim: To study the prevalence and distribution of dental anomalies in a sample of orthodontic patients. Methods: The dental casts, intraoral photographs, and lateral panoramic and cephalometric radiographs of 509 Egyptian orthodontic patients were studied. Patients were examined for dental anomalies in number, size, shape, position, and structure. The prevalence of each dental anomaly was calculated and compared between sexes. Results: Of the total study sample, 32.6% of the patients had at least one dental anomaly other than agenesis of third molars; 32.1% of females and 33.5% of males had at least one dental anomaly other than agenesis of third molars. The most commonly detected dental anomalies were impaction (12.8%) and ectopic eruption (10.8%). The total prevalence of hypodontia (excluding third molars) and hyperdontia was 2.4% and 2.8%, respectively, with similiar distributions in females and males. Gemination and accessory roots were reported in this study; each of these anomalies was detected in 0.2% of patients. Conclusion: In addition to genetic and racial factors, environmental factors could have more important influence on the prevalence of dental anomalies in every population. Impaction, ectopic eruption, hyperdontia, hypodontia, and microdontia were the most common dental anomalies, while fusion and dentinogenesis imperfecta were absent.
"In Europeans, the mandibular second premolar was most frequently absent, followed by the maxillary lateral incisor and second premolars 17—22. In the Malaysian , Turkish  and American populations , the most frequently missing tooth was the maxillary lateral incisor; and, in Chinese, it was the mandibular central and lateral incisors . The absence of maxillary central incisor , canine, first molar and second molar was rare. "
[Show abstract][Hide abstract] ABSTRACT: Tooth agenesis or hypodontia is one of the most common anomalies of the human dentition, characterized by the developmental absence of one or more teeth. Many studies have reported that the prevalence of congenital absence of permanent teeth varies from 3% to 11% among European and Asian populations. Recent advances in the fields of molecular biology and human genetics have improved our understanding of the cause of tooth agenesis. In this review, we assess the previous literature on prevalence of tooth agenesis comparing the Japanese with other racial populations, and describe the recent genetic studies associated with hypodontia in human and mouse models.
Japanese Dental Science Review 05/2009; 45(1):52-58. DOI:10.1016/j.jdsr.2008.12.001
[Show abstract][Hide abstract] ABSTRACT: ObjectivesThe aim of this investigation was to evaluate the dental and craniofacial characteristics of subjects with amelogenesis imperfecta
(AI) using lateral cephalometric radiography.
MethodsThe sample consisted of the lateral cephalometric radiographs of 20 AI patients, irrespective of orthodontic malocclusion,
and 18 healthy control subjects. Commonly used cephalometric measurements (8 linear, 6 angular) were compared between groups.
Differences were tested with analysis of variance and Duncan’s test. Intra-class correlation coefficients were used to examine
ResultsThe AI group displayed significant differences from the control group, indicating a tendency towards a skeletal open-bite
malocclusion (p<0.01). Despite the random selection of AI cases, the mean intermaxillary relationship of the AI group fell within the Class
I malocclusion type. The AI group showed increased anterior facial height (p<0.01) and decreased posterior facial height (p<0.01) in comparison with the control group. No significant difference was found in maxillary or mandibular effective lengths.
ConclusionsOpen-bite malocclusion was found in 35% of patients with AI. The mean vertical dimensions were increased in the AI group.
These characteristics are considered to be skeletal in origin, although the etiological relationship between AI and skeletal
disharmony remains unknown.
KeywordsAmelogenesis imperfecta-Craniofacial characteristics-Lateral cephalometric radiograph
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to evaluate the prevalence and distribution of dental anomalies, including other pathologic fi ndings in the pre-treatment records of Thai orthodontic patients at the Faculty of Dentistry, Khon Kaen University. Two observers retrospectively examined 570 panoramic radio-graphs, study models and pre-orthodontic records. Dental anomalies were recorded using panoramic radiographs and study models. The prevalence and distribution of the anomalies were assessed and reported as descriptive statistics. Patients were between 12 and 40 years of age(mean 19.38+4.23). Persons between 16 and 20 years of age comprised the most common age group (51.1%) requiring for orthodontic treatment. The patient types included: class I (25.3%), II (27.4%), III (13.2%) and superclass I (34.0%). Crowding and spacing were found in 89.6% and 73.2% of patients, respectively. It was found that 38.6% of patients had at least one dental anomaly: hypodontia being the most common (26.1%), followed by microdontia (13.7%), root shape abnormality (3.4%), hyperdontia (2.7%), transposition (1.6%), macrodontia (1.4%) and fusion 0.7%. In conclusion, the developmental dental anomalies found in Thai orthodontic patients were comparable with other research.
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