Laser-Doppler microvascular flow of dental pulp in relation to caries progression

Pulpal blood supply can be measured noninvasively and objectively via laser-Doppler fluxmetry. The aim of the study was to measure and compare pulpal laser-Doppler (LD) flux values for permanent non-carious teeth and carious teeth with different degrees of caries progression. Conventional sensitivity tests were also conducted for a comparative analysis to clarify the difference between tooth sensitivity and vitality. Carious lesions were detected and assessed in 15 adult subjects using the International Caries Detection and Assessment System (ICDAS) criteria. Pulpal sensitivity of selected carious teeth (without previous prosthetic restoration or endodontic treatment) and suitable caries-free teeth were then tested with a cold stimulus and subsequently with a weak electric current, whereas their pulpal LD flux was recorded at a separate visit using individually designed silicone probe holders. The LD flux values for teeth with an ICDAS score 6 were significantly lower compared to the values for teeth with an ICDAS score 1 (p < 0.05). Pulpal LD flux values of teeth with active caries were significantly lower than those of teeth with solely inactive carious lesions (p < 0.05). The degree of agreement between sensitivity and vitality testing was fair within both of the pairs: cold test/LDF (κk = 0.232, p = 0.00) and electric test/LDF (κk = 0.354, p = 0.00). Pulpal LD flux measurement proved to be reliable in the pulp vitality assessment of carious and non-carious teeth and might improve the reliability of clinical decisions when used in addition to standard clinical diagnostic protocols.