Carbohydrate material in carious dentine—I: Preliminary investigations

Carious dentine hydrolysates, prepared using strong mineral acid (6 N HCl), are brown and contain insoluble black material. However, hydrolysates of carious dentine prepared using 1.5 N sulphuric acid, 5 N formic acid, 2 N sodium hydroxide and collagenase, though light brown, were devoid of any black precipitate. Autoclaving dissolved 70 per cent of carious dentine, and the resultant light brown solution was also free of insoluble black material. These results indicated that the precipitate in strong mineral acid hydrolysates of carious dentine probably formed during the hydrolysis procedure. The possibility that this feature was due to the presence of carbohydrate material was supported by the results of carbohydrate analyses. It was found that carious dentine contained approximately 4 per cent “glucose” units of carbohydrate, in contrast to sound dentine which contained 0.4 per cent “glucose” units. Carious dentine contained material giving a positive Elson-Morgan reaction, but paper Chromatographic studies failed to indicate the presence of the amino-sugars glucosamine or galactosamine. The fractions of carious dentine resistant to collagenase action or autoclaving contained higher concentrations of carbohydrate material.