In vitro and in situ studies have demonstrated that the photodynamic antimicrobial therapy (PACT) is effective in reducing Streptococcus mutans population in artificially carious dentin.
This pilot in vivo study evaluated the antimicrobial effect of PACT using toluidine blue O (TBO) and a light-emitting diode (LED) in carious dentin lesions. Five healthy adult volunteers (19-36 yr), with at least 4 active carious cavities each, participated in this study. Teeth of each volunteer were randomly divided into four groups: (1) without TBO and without light (Control); (2) with TBO alone (TBO); (3) with LED at 94/J cm2 alone (LED); and (4) with TBO plus LED at 94 J/cm2 (PACT). Each cavity was divided into two halves. The baseline carious dentin sample was collected from half of each cavity. Following, the treatments were performed using a random distribution of tooth into treatments. Then, the second collection of carious dentin samples was performed. Before and after treatments, dentin samples were analyzed with regard
to the counts of total viable microorganisms, total streptococci, mutans streptococci, and lactobacilli. The data were statistically analyzed by Kruskal-Wallis and Student-Newman-Keuls
tests (α=5%). Log reductions ranged from -0.12 to 2.68 and significant reductions were observed for PACT (group 4) when compared to the other groups (1, 2, and 3) for total
streptococci and mutans streptococci. Concluding, PACT was effective in killing oral
microorganisms present in in vivo carious dentin lesions and may be a promising technique for
eliminating bacteria from dentin before restoration.