Oral biofilm and caries-infiltrant interactions on enamel

OBJECTIVES This study aimed to analyze interactions between oral biofilms and a dental triethylene glycol dimethacrylate (TEGDMA)-based resin infiltration material on enamel. METHODS Demineralized enamel specimens (14 days, acidic buffer, pH 5.0) were either infiltrated with a commercial TEGDMA resin and subjected to a three-species biofilm (Streptococcus mutans UAB 159, Streptococcus oralis OMZ 607 and Actinomyces oris OMZ 745) (group 1), applied to the biofilm (group 2), or merely resin infiltrated (group 3). A control group received no treatment (4). Biofilm formation and metabolic activity of biofilms were measured for group (1) and (2) after 24h CFU and a resazurin assay. Resin biodegradation was measured for group (1) and (3) by high performance liquid chromatography (HPLC) coupled with mass spectrometry after 6 and 24h incubation. Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) images were taken to study the biofilm and material's autofluorescence in groups (1-4) after 24h. RESULTS SEM and CLSM images showed reduced biofilm formation on resin-infiltrated specimens (group 1) compared to group 2, while no biofilm was detectable on groups 3 and 4. CFU data (log10 CFU per mL) of group 1 showed significantly reduced bacterial numbers (p