Monitoring of extracellular pH in young dental biofilms grown in vivo in the presence and absence of sucrose

摘要

Background and objectivepH in dental biofilms is of central importance for the development of caries. We used the ratiometric pH-sensitive dye C-SNARF-4 in combination with digital image analysis to monitor extracellular pH in dental biofilms grown in situ with and without sucrose supply.DesignDental biofilms (48 h) from 10 individuals were collected on glass slabs mounted on intra-oral appliances. During growth, appliances were immersed extra-orally in either physiological saline or 4% sucrose for 2 min, eight times per day. Fluorescence emissions of C-SNARF-4 in deep layers of the biofilms were recorded ex vivo with confocal microscopy for 15 min or for 1 h after exposure to 0.4% glucose. Extracellular pH was determined ratiometrically using digital image analysis.ResultsExtracellular pH dropped rapidly in most examined sites after addition of glucose. Distinct pH microenvironments were observed within single biofilms. The variation in pH was similar between sites within the same biofilm and sites from ...