Fluoride and calcium concentration in the biofilm fluid after the use of fluoridated dentifrices supplemented with sodium trimetaphosphate or calcium glycerophosphate, under cariogenic challenge

Objectives: The present study evaluated fluoride (F) and calcium (Ca) concentrations in the biofilm fluid formed in situ under cariogenic challenge after using F dentifrices supplemented or not with sodium trimetaphosphate (TMP) or calcium glycerophosphate (CaGP).
Methods: Volunteers (n=12) were randomly divided into 5 groups according to the toothpastes used: Placebo (no F, CaGP or TMP), conventional dentifrice (CD, 1100 ppm F) and low-fluoride dentifrice (550 ppm F) with no supplementation (550F) or supplemented with 1% TMP (550F-TMP) or 0.25% CaGP (550F-CaGP). In each phase, volunteers wore palatal appliances containing 4 bovine enamel blocks. Cariogenic challenge was performed with 30% sucrose solution, 6 times/day. On the morning of the 8^th day, biofilm samples were collected 12h and 1h after brushing and cariogenic challenge. F and Ca analyses in the biofilm fluid were performed with the inverted electrode after buffering with TISAB III and using the Arsenazo III method, respectively. Data were submitted to 2-way ANOVA (repeated measures) and Student-Newman-Keuls test (p<0.05).
Results: A dose-response relationship was verified between F concentrations in the dentifrices and in the biofilm fluid. Significant differences were observed among Placebo, 550F and 1100F only 1 h after brushing, without statistical differences among 550F, 550F - TMP and 550F - CaGP. No defined trend was observed among the groups regarding Ca concentrations, with the highest values seen for Placebo and 550F - CaGP.
Conclusions: It was concluded that the anticaries effects of LFDs supplemented with CaGP or TMP cannot be related to an increased availability of F and Ca in the biofilm fluid.