Table 3. Soluble and bound fluoride in biofilms (μmol F/g) formed on enamel and dentine slabs, according to the treatments (mean ± SD; n = 12).

Treatmentsα (ppm F)	Soluble F β		Bound F
	Enamel	Dentine	Enamel	Dentine
0 (control)	0.33±0.07A,a	γ0.30±0.09 A,a	0.17±0.08 A,a	0.12±0.07 B,a
150	1.93±0.49 A,b	2.25±0.39 A,b	0.22±0.09 A,a	0.31±0.31 A,b
450	2.89±0.54 A,c	4.37±1.03 B,c	0.23±0.07 A,a	0.32±0.15 A,b
1,350	4.65±1.07 A,d	7.63±1.53 B,d	0.28±0.11 A,a	0.46±0.30 B,b

Distinct capital letters indicate differences (p < 0.05) between enamel and dentine for soluble and bound fluoride (values within lines). Distinct lower case letters indicate differences (p < 0.05) among treatments (values in columns for each condition).

^α Concentrations to simulate brushing with toothpaste from low to high F concentration, considering the dilution (1:3) by saliva.

^β values transformed by log 10 to statistical analysis;

^γ outlier removed, value = 0.74 mol F/g biofilm.