Living with one or none of the parents, had no significant effect on caries severity in our study. As minority of participants are living with 1 or none of their parents, in other words most of the pupils are living with both of their parents, there-fore further detailed studies are needed to make any conclusion about the relation between the ef-fect of this factor on caries severity . In addition, in the present study, consanguineous relationship between the parents, parents’ educa-tion and birth rank, had no significant effect on caries severity in the subjects. Therefore, the fam-ily structure in this study was not an effective fac-tor in dental caries..