The effect of different concentrations of citrate in drinks on plaque pH.

The effect of 0.1, 0.2 and 0.4% citrate in 10% sucrose solutions on the plaque pH in vivo was tested in 20 volunteers using the plaque harvesting technique. Results showed that the pH response for the three test solutions with citrate was significantly less compared with that for 10% sucrose (positive control) alone (p < 0.05). Mean areas under the pH curve were: sorbitol (negative control) 0.02, citrate 0.2% 5.30, citrate 0.4% 6.24, citrate 0.1% 6.94 and 10% 12.69. The cariogenic potential index of all the citrate test drinks was almost half compared with a 10% sucrose solution (p < 0.05). It was concluded that the addition of relatively low levels of citrate in a sucrose solution reduces the acidogenic response in the plaque.