An in vitro study of the pH-lowering potential of salivary lactobacilli associated with dental caries

Aims: Lactobacilli are known to produce acids from sucrose or glucose. This acid production can cause a drop in pH which is sufficiently significant t o demineralize the hard tissues of the teeth. Some authors have demonstrate d the benefits of substituting sorbitol or xylitol for sucrose, The aim of this work was to study the acid production of salivary lactobacilli with on e test sugar (glucose) and two polyols (sorbitol and xylitol). Methods and Results: The pH-lowering potential of three strains of oral lac tobacilli was recorded with glucose or one of the polyols at three differen t concentrations. The results showed that polyols were broken down by certa in strains of lactobacilli. When this degradation took place, the pH droppe d to values sufficiently low to demineralize the hard tissues of the teeth. Conclusions: Further studies must be carried out on the metabolism of polyo ls before encouraging their widespread substitution for sucrose.