Prolonged nursing-habit caries index

The purpose of this study was to test the reliability and validity of a new index designed to assess prolonged nursing-habit caries (PNHC) in the primary dentition. The labial surfaces of maxillary primary incisors of 2389 nursery-school children (age range 12-53 months) were examined for the severity of PNHC, graded from 0 to 5. Intra-examiner reliability was assessed by twice examining 51 children across a 1-month interval. Inter-examiner reliability was assessed at one examination of 113 children. The reliability measures were positive; the correlation coefficient was 0.97 (p less than 0.01) for both. Validity was assessed by relating the PNHC index to the deft index. The correlation coefficient between the PNHC index and the deft was 0.68 (p less than 0.01). These findings suggest that PNHC index is both reliable and valid and could be used in future research.