Investigation of the relation between socio-cultural variables and dental health. Opinions on dental care, dental health / opinions on, contacts with dentist / dental health-knowledge / influence parents on dental care / toothbrushing frequency / eating habits / consumption of sweets, candy / influence of parents on eating sweets / opinion on effects of eating sweets on dental health / detailed data ( opinions, attitudes, behaviour ) from mother regarding dental matters of self and child / health insurance / special dental care programs for youth / fluoride tablets / objective data on dental health situation of child. Background variables: basic characteristics/ household characteristics/ characteristics of parental family/household/ occupation/employment/ income/capital assets/ education/ religion