Sucrose application frequency and dental biofilm fluid composition

“Objectives:”, To evaluate if the inverse relationship between sucrose exposure and low concentration of calcium (Ca), inorganic phosphate (Pi) and fluoride (F) observed in whole dental biofilm is also found in the biofilm fluid. “Methods:”, During three phases of 14 days each, ten volunteers wore palatal appliances containing blocks of human enamel, which were extra-orally submitted to 20% sucrose solution from 0 (negative control), 2, 4, 6, 8 and 10 times/day. The biofilm formed on the blocks was collected, and its fluid was separated by centrifugation. The precipitated (‘whole plaque') was treated with 0.5 M HCL to extract acid soluble inorganic components. Ca, Pi and F concentrations were determined in biofilm fluid and ‘whole plaque' by microtechniques. “Results:”, The found inverse relationship between Ca, Pi and F concentrations in ‘whole plaque' and frequency of sucrose exposure was confirmed (p<0.05). However, the same pattern was not found in the biofilm fluid; Pi and F concentration in the fluid of plaque exposed to any frequency of sucrose did not differ from the negative control (p>0.05). Furthermore, Ca concentration was higher when the biofilm was exposed to sucrose 8-10x/day (p<0.05) compared with the negative control. “Conclusions:”, The findings show that the change induced by frequent sucrose exposure in the ‘whole plaque' do not reflect in the biofilm fluid, suggesting that the reduced pool of Ca, Pi and F in ‘whole plaque' would not contribute to the high cariogenicity of the biofim formed in presence of this carbohydrate. (Supported by FAPESP, Proc.2004/13963-2)