Influences of Sucrose and Buffer Additives on Plaque and ³²P of the Enamel

¹ Eastman Dental Center, Rochester, New York

Neutron-irradiated enamel granules were covered with homogenized dental plaque and saliva. On incubation, the presence of sucrose in saliva resulted in a pH drop in the plaque to about pH 5. It also increased the appearance of the ³²P of enamel origin in the plaque-saliva environment by 100 percent beyond the value of the equilibrated nonsugar control system. Addition of NaHCO₃+NH₄H₂PO₄ into the sugar-containing saliva prevented the pH drop of the plaque and reversed the effect of fermentation on the liberation of the enamel ³²p.

The amount of ³²P activity in the control plaque material varied from 18 percent to 37 percent of the total released from the enamel.

An increased uptake of ³²p of enamel origin by plaque in the presence of glucose was demonstrated by use of a saliva-free modification of the present system.