The Effects of Magnification on Caries Detection

The visual International Caries Detection and Assessment System criteria (ICDAS) does not require the use of magnification to correlate clinical signs of caries lesion severity with histological depth. However, it is possible that the visual perception of caries severity might change with use of magnification. Loupes commonly used in US dental practice today offer magnifications of 2.5x and 3.5x. Objective: To compare the effects of magnification use (2.5x and 3.5x) on visual caries detection criteria scores. Methods: Sixty permanent human molars were selected using the ICDAS criteria without the use of magnification. Lesion severity scores ranged from 0-4 (10 teeth/caries lesion category; 20 teeth sound). Teeth were randomly numbered and mounted in five “dentaform-mannequin” models. Dental examinations were done in simulated dental conditions by one trained and calibrated examiner using unaided vision (0x) and two magnifications (2.5x and 3.5x). In order to measure reproducibility, a select number of models were re-examined. Results: Intra-examiner repeatability for the ICDAS severity scores was acceptable for the 0x (81% agreement, weighted kappa 0.79) and 2.5x magnification (83% agreement, weighted kappa 0.77); nearly perfect for the 3.5x magnification (93% agreement, weighted kappa 0.97). Agreement of the 0x magnification ICDAS severity scores with the ICDAS scores used during tooth selection was acceptable (77% agreement, weighted kappa 0.82). The 0x and 2.5x ICDAS severity scores were not significantly different (p=0.69). The 3.5x ICDAS severity scores were marginally higher than the 0x scores (p=0.051) and significantly higher than the 2.5x scores (p=0.0043). Conclusion: It is concluded that under the conditions of this study use of 2.5x magnification did not affect intra-examiner reproducibility or lesion severity score decision compared to unaided examination. Furthermore, the use of 3.5x magnification improved the intra-examiner reproducibility; however, it resulted in higher lesion severity scores. This study was supported by a grant from IUSD.