Genetic Pattern of Dental Caries in Families from a City in Southern Brazil

Fatores geneticos desempenham um importante papel na susceptibilidade a carie dentaria na populacao. O objetivo deste estudo foi investigar, por meio da analise de segregacao complexa (ASC), o padrao intergeracional da ocorrencia da carie dentaria em familias brasileiras. O estudo foi epidemiologico genetico, observacional e transversal. A amostra foi constituida de 21 familias que exibiam altos niveis de carie (CPOD>4.5). Os participantes passaram por avaliacao bucal, sendo que a carie dentaria foi registrada de acordo com o indice CPOD (dente cariado, perdido e obturado), seguindo as diretrizes da Organizacao Mundial de Saude, bem como a presenca de gengivite foi avaliada utilizando o indice de sangramento gengival. Foi aplicado um questionario para identificacao dos fatores socioenconomicos e praticas de saude bucal. Analises de regressao linear simples e multipla foram realizadas para testar a associacao entre carie dentaria e as variaveis independentes. A significância estatistica foi considerada no nivel de 5%, a ASC foi interpretada pelo programa S.A.G.E. A prevalencia de carie foi de 89,2%. Na analise multipla, apenas a gengivite permaneceu associada (p = 0,005). A analise visual dos genogramas identificou um padrao familiar que sugere a predominância do modelo autossomico dominante. A frequencia do alelo de resistencia "A" foi estimada em 0,22. O valor medio de carie foi de 1,35 para os genotipos AA e AB e de 3,95 para o BB. Os resultados do presente estudo fornecem evidencias da presenca de um gene importante com efeito dominante no controle do desenvolvimento de carie dentaria dentro da mesma familia.   Palavras-chave: Carie Dentaria. Epidemiologia Genetica. Reabilitacao Oral. Susceptibilidade. Abstract Genetic factors may play an important role in the susceptibility to dental caries of the human population. The objective of this study was to investigate, by means of complex segregation analysis (CSA), the intergeneration pattern in the occurrence of caries in Brazilian families. This was a cross-sectional, observational genetic epidemiological study. The sample consisted of 21 families whose probands exhibited high levels of caries (DMFT>4.5). All participants underwent an oral examination. Dental caries was recorded according to the DMFT index (decayed, missing, and filled teeth), according to World Health Organization guidelines and the presence of gingivitis was assessed by using the gingival bleeding index. A questionnaire was applied to identify the sociodemographic profile and practices on oral health. Simple and multiple linear regression analysis were performed to test the association between dental caries and the independent variables. Statistical significance was considered at the 5% level. The S.A.G.E program drove the CSA. The prevalence of caries was 89.2%. In the multiple analysis only gingivitis remained associated (p = 0.005). The visual analysis of genograms identified a family pattern that suggests the predominance of the autosomal dominant model. The frequency of resistance allele "A" was estimated at 0.22. The mean decay value was 1.35 for AA and AB genotypes and 3.95 for BB. The results of the present study provide evidence as to the presence of a major gene with a dominant effect controlling the appearance of dental caries, within the same family.   Keywords: Dental Caries. Genetic Epidemiology. Oral Rehabilitation. Susceptibility.