Validity of quantitative values of quantitative light-induced fluorescent (QLF) device for pulp diagnosis of teeth with cracks.

Introduction: The Quantitative Light-Induced Fluorescence (QLF) device provides both the visual information of crack lines on tooth surfaces and quantitative values for fluorescence reactions. The aim of this study was to evaluate the correlation and assess the usefulness of QLF quantitative values in pulp diagnosis of teeth with cracks.

Methods: Pulp diagnosis was performed on 76 teeth with cracks according to the American Association of Endodontics's guidelines, and their QLF images were captured. The crack lines of the QLF images were quantitatively analyzed using the QLF software CrazeLineWizard01. QLF quantitative values (ΔF: fluorescence loss unit, ΔFmax: maximum of fluorescence loss unit, ΔR: red fluorescence gain unit, ΔRmax: maximum of red fluorescence gain unit) according to the pulp diagnosis of teeth with cracks were analyzed using one-way ANOVA. Multinomial logistic regression analysis was conducted to calculate the prediction of pulp diagnosis on QLF quantitative values. The correlation between the predicted pulp diagnosis and the clinical pulp diagnosis was compared using Pearson's correlation coefficient.

Results: ΔF and ΔF max decreased with the progression of pulp disease in cracked teeth, while ΔR and ΔR max increased. Significant differences were found between irreversible pulpitis and pulp necrosis (p < 0.05). Pearson correlation coefficients between predicted and clinical pulp diagnosis based on multinomial logistic regression analysis of QLF quantitative values ranged from 0.699 to 0.806. The accuracy of prediction​​was up to 82.1 % for reversible pulpitis, 73.1 % for irreversible pulpitis, and approximately 80.0 % for pulp necrosis.

Conclusions: The quantitative values from the QLF device demonstrate its potential for predicting the severity of pulp disease caused by tooth cracks.

Clinical Significance: The quantitative values of QLF images acquired with a QLF device, which provide visual information on crack lines of teeth through fluorescence reactions on the tooth surface, showed a significant correlation and predictive value for pulp diagnosis as pulp disease progressed in teeth with cracks.