Clinical dental examination
Dental examinations at 4 years were performed by the same blinded examiner of the first year followup. Teeth were brushed and dried with gauze, and each dental surface was inspected with the help of a mouth mirror under artificial light. Following the National Institutes of Health (NIH) case definitions (20), occurrence of ECC (primary outcome) was defined as the presence of one or more decayed(d1+), missing or filled tooth surfaces in any primary tooth (d1+mfs ‡ 1).