Agenesis of maxillary lateral incisors and associated dental anomalies.

INTRODUCTION: The objectives of this study were to evaluate the prevalence of dental anomalies in patients with agenesis of maxillary lateral incisors and to compare the findings with the prevalence of these anomalies in the general population. METHODS: A sample of 126 patients, aged 7 to 35 years, with agenesis of at least 1 maxillary lateral incisor was selected. Panoramic and periapical radiographs and dental casts were used to analyze other associated dental anomalies, including agenesis of other permanent teeth, ectopia of unerupted permanent teeth, microdontia of maxillary lateral incisors, and supernumerary teeth. The occurrence of these anomalies was compared with prevalence data previously reported for the general population. Statistical testing was performed with the chi-square test (P <0.05) and the odds ratio. RESULTS: Patients with maxillary lateral incisor agenesis had a significantly increased prevalence rate of permanent tooth agenesis (18.2%), excluding the third molars. The occurrence of third-molar agenesis in a subgroup aged 14 years or older (n = 76) was 35.5%. The frequencies of maxillary second premolar agenesis (10.3%), mandibular second premolar agenesis (7.9%), microdontia of maxillary lateral incisors (38.8%), and distoangulation of mandibular second premolars (3.9%) were significantly increased in our sample compared with the general population. In a subgroup of patients aged 10 years or older (n = 115), the prevalence of palatally displaced canines was elevated (5.2%). The prevalences of mesioangulation of mandibular second molars and supernumerary teeth were not higher in the sample. CONCLUSIONS: Permanent tooth agenesis, maxillary lateral incisor microdontia, palatally displaced canines, and distoangulation of mandibular second premolars are frequently associated with maxillary lateral incisor agenesis, providing additional evidence of a genetic interrelationship in the causes of these dental anomalies.

Anomalias dentárias associadas: o ortodontista decodificando a genética que rege os distúrbios de desenvolvimento dentário / Associated dental anomalies: the orthodontist decoding the genetics which regulates the dental development disturbances

O presente trabalho versa sobre o diagnóstico e a abordagem ortodôntica das anomalias dentárias, enfatizando os aspectos etiológicos que definem tais irregularidades de desenvolvimento. Parece existir uma inter-relação genética na determinação de algumas dessas anomalias, considerando-se a alta frequência de associações. Um mesmo defeito genético pode originar diferentes manifestações fenotípicas, incluindo agenesias, microdontias, ectopias e atraso no desenvolvimento dentário. As implicações clínicas das anomalias dentárias associadas são muito relevantes, uma vez que o diagnóstico precoce de uma determinada anomalia dentária pode alertar o clínico sobre a possibilidade de desenvolvimento de outras anomalias associadas no mesmo paciente ou em outros membros da família, permitindo a intervenção ortodôntica em época oportuna.

This article aims to approach the diagnosis and orthodontic intervention of the dental anomalies, emphasizing the etiological aspects which define these developmental irregularities. It seems to exist a genetic inter-relationship determining some dental anomalies, considering the high frequency of associations. The same genetic defect may give rise to different phenotypes, including tooth agenesis, microdontia, ectopias and delayed dental development. The clinical implications of the associated dental anomalies are relevant, since early detection of a single dental anomaly may call the attention of professionals to the possible development of other associated anomalies in the same patient or in the family, allowing timely orthodontic intervention.

Estudo epidemiológico da agenesia de segundos pré-molares e sua relação com a agenesia de outros dentes permanentes / Epidemiological investigation of second premolar agenesis and its relationship with agenesis of other permanent teeth

Objective ? This study aims to evaluate the epidemiological characteristics of a sample of patients with agenesis of second premolars, as well as to investigate its association with agenesis of other permanent teeth. Material and methods ? A Brazilian sample of 203 patients aged from 8 to 22 years was selected, all patients presenting agenesis of at least 1 second premolar. Patient age, gender and ethnicity were recorded, as well as the history of extraction of permanent teeth and associated agenesis of other permanent teeth. Results: ? Most individuals presenting second premolar agenesis were female (66%), a sex ratio of 2F: 1M. The frequency of second premolar agenesis was higher in the mandible (61.5%) than in the maxilla (16.7%), while 21.6% of the patients showed second premolar agenesis affecting both arches. The prevalence of unilateral and bilateral agenesis was similar (50%) in the maxilla, while in the mandible 60% of the sample exhibited unilateral agenesis. The mandibular left hemi arch was the most frequently affected. Most of the patients (45.3%) had agenesis of just 1 second premolar. There was a high prevalence of agenesis of other permanent teeth associated with second premolar agenesis, especially of maxillary lateral incisors (16%) and third molars (48%). Conclusion: Agenesis of second premolars was more prevalent in females and at the left side of the mandibular arch and was often associated with agenesis of other permanent teeth.

Objetivo ? O presente trabalho visa avaliar as características epidemiológicas de uma amostra de pacientes com agenesia de segundos pré-molares, assim como verificar a sua associação com a agenesia de outros dentes permanentes. Material e métodos ? Foi avaliada a documentação ortodôntica de 203 pacientes brasileiros com idade entre 8 e 22 anos, apresentando agenesia de pelo menos um segundo pré-molar. Foi feito o registrado de: idade do paciente, sexo e etnia, histórico de extrações de dentes permanentes e presença de agenesias de outros dentes permanentes associadas. Resultados ? A maior parte da amostra era composta pelo sexo feminino (66%), apresentando oddes ratio de 2F: 1M. A agenesia de segundo pré-molar mostrouse mais prevalente no arco inferior (61,5%) do que no superior (16,7%), enquanto que 21,6% mostraram a referida agenesia em ambos os arcos. Os valores percentuais obtidos para agenesia tanto unilateral quanto bilateral foram semelhantes (50%) no arco dentário superior, enquanto que, no arco dentário inferior, 60% da amostra apresentaram agenesia unilateral. A maioria dos pacientes (45,3%) apresentou agenesia de apenas 1 segundo pré-molar. Observou-se uma alta prevalência de agenesia de outros dentes permanentes associada à agenesia de segundos pré-molares, principalmente dos incisivos laterais superiores (16%) e dos terceiros molares (48%). Conclusão: A agenesia dos segundos pré-molares foi mais prevalente no sexo feminino, no arco inferior do lado esquerdo e mostrou-se frequentemente associada a outras agenesias de dentes permanentes.