Degradation of maltose and starch by human saliva and by supernatants of dental plaque material.

The pH-decrease in dental plaque in vivo after mouth rinses with solutions of sucrose and maltose has been compared. No statistically significant differences were found between the results obtained with these two disaccharides. Pooled samples of parotid saliva, centrifuged whole saliva and dental plaque supernatants were separated with the isoelectric focusing technique. The results suggest that maltose is hydrolysed in parotid saliva by the salivary alpha-amylase and in dental plaque by enzymes from sources other than the salivary glands, probably microorganisms. No bacterial alpha-amylases, separated from salivary alpha-amylase, were found in whole saliva specimens or in dental plaque supernatants. Quantitative determinations of "maltase" and amylase activities in parotid saliva, centrifuged whole saliva and dental plaque supernatants from 10 subjects were carried out. The highest enzyme activity of "maltase" was found in the samples of dental plaque and the highest amylase activity in parotid saliva specimens.