Detection of Apical Dental Resorption Caused by Endodontic Infection in Mice Using Fluorescence and Bright-Field Microscopy

The aim of this study was to evaluate the sensitivity, specificity, and predictive values of the fluorescence microscopy method in the detection of apical dental reabsorption after induction of apical periodontitis in animal models. Forty-first molars of mice, aged 6 to 8 weeks, had their root canals exposed to the oral environment or were maintained healthy as controls (n = 20). After 14 and 42 days, mice were euthanized and tissues were collected for histological evaluation by means of bright field and fluorescence microscopy. The accuracy of fluorescence microscopy in identifying apical external dental resorption was investigated using a diagnostic validation test based on the sensitivity (S) and specificity (E) properties. Bright-field microscopy revealed a higher number of specimens with scores of 1 to 3 - absence of apical dental resorption (n = 29; 52%), while fluorescence microscopy revealed a higher number of specimens with scores of 4 to 6 - presence of apical dental resorption (n = 37; 66%). Out of 56 specimens, 26 were TP, 11 were FP, and 19 were TN. No FN result was observed. Fluorescence microscopy presented a sensitivity value of 1, similar to the bright-field method, while specificity was lower (0.633). The accuracy of the fluorescent method to detect apical dental resorption was 0.804. Fluorescence microscopy revealed a higher number of false positive apical dental resorption than bright-field microscopy. The detection of apical dental resorption was not impacted by the sensitivity of the method but by its specificity.