MATERIALS AND METHODS: Thirty single canal extracted human teeth with patent apical foramen were selected. Access cavities were prepared. Anatomic length (AL) was determined by inserting a K-file into the root canal until the file tip was just visible at the most coronal aspect of the apical foramen; subsequently 0.5 mm was deducted from this measured length. Working length by radiographic method (RL) was determined using Ingle's method. Propex II apex locator was used to determine the electronic working length (EL). From these calculated lengths, AL was deducted to obtain D-value. D-value in the range of +/-0.5 mm was considered to be acceptable.

RESULTS: The percentage accuracy of RL and Propex II apex locator was 76.6% and 86.6%, respectively. Paired t-test revealed significant difference between the RL and Propex II apex locator (P<0.05).

MATERIALS AND METHODS: Dental students (n = 122) in their clinical years, year 3 (n = 37), year 4 (n = 44), and year 5 (n = 41) received training (two-hour introductory lecture on ICDAS, followed by a 90 min e-learning video, and practice sessions using extracted teeth and photographs) from a calibrated expert. After training, the students examined a prevalidated set of extracted teeth and assigned scores in two sessions. The intra- and inter-examiner agreement between students was analyzed using weighted kappa statistics and a focus group discussion was conducted for qualitative feedback.

RESULTS: The range of kappa values for intra-examiner agreement among the year 3, 4, and 5 students for ICDAS caries code (0.611-0.879, 0.633-0.848, and 0.645-1.000) and restoration code (0.615-0.942, 0.612-0.923, 0.653-1.000), respectively. The range of kappa values for inter-examiner agreement for year 3, 4, and 5 students with a trained expert for ICDAS caries code (0.526-0.713, 0.467-0.810, and 0.525-0.842) and restoration code (0.531-0.816, 0.682-0.842, and 0.645-0.928), respectively.

CONCLUSION: The ICDAS system is a promising tool for caries detection and its implementation in the curriculum was perceived by dental students as an effective method. In general, there was moderate to substantial agreement for ICDAS caries and restoration code between students of different academic year groups and with a trained ICDAS expert.