Magnification Effect on Caries Detection and Treatment by Early Learners

Objectives: To determine the effect of magnification on detection and treatment decisions of occlusal caries lesions by second year DDS students (early learners).
Methods: 128 permanent human molars were selected using the International Caries Detection and Assessment System II criteria (severity scores 0-5; 16 sound and 18 for each caries category), mounted in nine “dentoform mannequin” models simulating clinical conditions, and assessed in random order by 6 students for ICDAS score (0-5) and treatment choices [none, non-invasive (fluoride/sealants), invasive-restorative] using 1x and three magnifications (2x, 3x, 5x). 30% of models were re-examined to determine intra-examiner repeatability.
Results: Overall intra-examiner repeatability was acceptable in determining ICDAS score (ICC mean>0.68), but varied by examiner. There was a decreasing, non-significant (p>0.05) trend in intra-examiner repeatability for ICDAS scoring as magnification increased, ranging between 0.80 for 1x to 0.68 for 5x. The intra-examiner repeatability for treatment choices did not significantly change with magnification (ICC mean range 0.57-0.65; p>0.05). Inter-examiner agreement for ICDAS detection scores was significantly higher (ICC mean=0.71) with 1x than with magnification (ICC mean=0.61, 0.67 and 0.58, respectively, for 2x, 3x and 5x). The inter-examiner repeatability for treatment choices was similar for all magnification groups (ICC mean range 0.45-0.56), but was significantly higher for 3x (ICC mean=0.56) than 5x (ICC mean=0.45).There was a strong correlation between treatment choice and ICDAS, and this was not significantly impacted by magnification (98-99% no treatment for ICDAS 0; restorative decisions increased as lesion severity increased: 0-1% for ICDAS 1-2, 59-93% for ICDAS 3-4, 99-100% for ICDAS 5).
Conclusions: Under the conditions of the study, early learners had acceptable ICC scores for intra and inter-examiner caries detection scores using 1x, with a trend towards decreased scores with increased magnification. The ICC scores were more modest and similar amongst the different magnification groups when assessing treatment decision choices.