Methods: 322 pairs of twins aged 18 months to seven years were enrolled for the study. Two examiners examined all primary molars. NIDCR caries index was modified to assign scores for the clinical exam: 1-white spot lesions; 2- lesions confined to enamel with loss of intact surface; 3- lesions with visible dentin breakdown; 4- lesions > 2-3mm into dentin. The IRLF (DIAGNOdent, KAVO, Biberach/Rib, Germany) measurements were performed on the fissures and readings were indexed based on the instrument output: 0 = 0-9 output; 1 = 10-17; 2 = 18-99. Examiner one performed the clinical exam on one twin while examiner two performed IRLF on same twin. Examiner’s tasks were reversed for the second twin. Reliability (Cronbach’s a) was calculated between lesion severity with and without bite-wings and IRLF output.
Results: Visual and radiographic exam showed high correlations for the molar teeth (a = 0.94 – 0.97). Visual inspection with IRLF showed lower correlation (a = 0.57 - 0.73). Correlation was similar when visual inspection plus radiographic exam were compared to IRLF (a = 0.54 – 0.71). In about 50 % of the observations visual inspection plus radiographic exams revealed the presence of an incipient lesion and the IRLF had an output of 0 to 9.
Conclusion: Correlations between IRLF and visual inspection and/or radiographic examination were lower than correlations between visual inspection and radiographic exams. This study was partially supported by NIH/NIDCR grants DE13534 and DE014528