In vitro study on the influence of the Antimicrobial Photodynamic Therapy on the polimicrobian biofilm made of bacteria from human saliva

Abstract

The present study aims to evaluatein vitro effect of antimicrobial photodynamic therapy (aPDT) on the viability of specific bacterial groups from polymicrobial biofilms and to determine the influence of therapeutic effects on the production of lactic acid by the same biofilm grown in medium supplemented with sucrose. Stimulated saliva is collected from a child aged between 7 and 11 years at high risk for tooth decay and used to polymicrobial biofilm growth on bovine dentin blocks for 72 h. Subsequently, aPDT is performed by associating one light emitting diode (630 nm) with two different photosensitizing dyes, methylene blue (MB)and blue ortho-toluidine (TBO). The CFU counts of total viable microorganisms (Tryptone Soy Agar Blood), total streptococci (Agar SalivariusMitis), mutans streptococci (MitisSalivarius Agar with bacitracin 0.2%) and lactobacilli (Rogosa Agar with glacial acetic acid at 0 13%) will be determined. The enzymatic spectrophotometric method will be used to evaluate the concentration of L-lactate in the culture medium. Statistical analysis will be conducted after the preliminary selection of statistical tests based on normality and homogeneity of data. The significancelevel for alltestsis 5%.