Through multiple logistic regression an epidemiological study was undertaken of the following factors: age, gender, socio-economic status, dental care, toothbrushing, chewing gum, snacking, fluoride, and of their influence on the development of tooth decay. The factors are analysed individually and globally (global model). An initial model was constructed, establishing the interactions, and developing a final model. Risk factors shown to be involved were: low social class status, lack of dental care in the previous 12 months, absence of toothbrushing, and belonging to the age group 9-12 years old. An interaction was established between the following variables: socio-economic status and toothbrushing, and dental care and age.