Diagnostic Performance of an Intraoral Scanner for Caries Detection on Permanent Tooth Surfaces

Intraoral scanners with fluorescence technology (IOSFT) include a caries detection feature in addition to their standard scanning function. The aim of this study was to determine the diagnostic performance of the caries detection tool of the IOSFT Trios 4® on permanent premolar and molar surfaces when compared to visual and radiographic International Caries Detection and Assessment System (ICDAS).

Participants (n = 71, age 6-88 years) were examined under standardised conditions using ICDAS criteria for visual caries detection of occlusal and smooth surfaces. Bitewing (BW) radiographs were used to examine proximal surfaces using ICDAS radiographic criteria. Finally, participants underwent an intraoral scan of both the maxilla and the mandible according to the manufacturer's instructions. The automated caries detection (ACD) output on the IOSFT software was compared to the visual ICDAS scores obtained clinically for occlusal and free smooth (buccal and lingual) surfaces; the IOSFT caries detection output was compared to radiographic ICDAS scores from BW radiographs for interproximal (mesial and distal) surfaces. Sensitivity, specificity, and accuracy values for each tooth surface were calculated.

Out of 3,684 permanent tooth surfaces examined, 461 surfaces with dental caries were included in the analysis. 392 were initial lesions (ICDAS 1-2), while 69 were moderate/severe (ICDAS 3-6). There was a moderate positive correlation (r = 0.4, p < 0.001) when comparing all ICDAS scores to IOSFT ACD categories for unrestored permanent occlusal surfaces. IOSFT ACD accuracy was higher for moderate/advanced lesions (ICDAS 3-6) lesions when compared to initial (ICDAS 1-2) ones (81% vs. 37.7%). For unrestored smooth surfaces, weak positive correlations were found when comparing all ICDAS scores to IOSFT ACD categories (r = 0.19, p < 0.001). Accuracy results for smooth surfaces were 93.5% for moderate/advanced and 77.1% for initial lesions. Correlations between BW ICDAS scores and IOSFT ACD scores for proximal surfaces were weak (r = 0.07, p = 0.019). Diagnostic accuracy was higher for moderate/advanced lesions when compared to initial ones (83.5% vs. 40.4%). There was a weak correlation between IOSFT ACD categories and ICDAS/visual categories for restored occlusal surfaces (r = 0.029, p = 0.68).

IOSFT cannot currently replace visual and radiographic exams for caries detection.