Table 1. Mean (+/−SD) changes (losses or uptakes) in dissolved calcium ion concentration in the in vitro enamel demineralization assay.

	0 hr	1 hr	2 hr	4 hr	8 hr	24 hr
Loss, baseline	−4.3 ± 0.8
Uptake, baseline	0.4 ± 0.3
Net, baseline	−3.8 ± 0.7
Loss, strip without F		−6.2 ± 0.9	−6.2 ± 0.9	−6.0 ± 0.8	−6.1 ± 0.8	−6.3 ± 1.0
Loss, fluoride strip		0.3 ± 0.3	0.7 ± 0.3	1.1 ± 0.7	1.6 ± 0.3	2.4 ± 0.5
Loss, toothpaste		−0.5 ± 0.2	−0.4 ± 0.9	−0.3 ± 1.1	0.1 ± 0.8	1.4 ± 0.6
Uptake, strip without F		−0.1 ± 0.1	−0.3 ± 0.3	−0.4 ± 0.2	−0.4 ± 0.2	−0.4 ± 0.2
Uptake, fluoride strip		1.1 ± 0.2	1.2 ± 0.3	2.9 ± 0.3	3.2 ± 0.4	3.5 ± 0.3
Uptake, toothpaste		0.6 ± 0.3	0.9 ± 0.2	1.5 ± 0.2	2.1 ± 0.3	2.4 ± 0.4
Net, strip without F		−6.2 ± 1.0	−6.5 ± 1.0	−6.4 ± 0.9	−6.6 ± 0.8	−6.7 ± 1.0
Net, fluoride strip		1.4 ± 0.1a	1.8 ± 0.2a	3.9 ± 0.5b	4.5 ± 0.7c	5.9 ± 0.3d
Net, toothpaste		−0.1  ±  0.3e	−0.1 ± 0.6e	1.2 ± 0.9f	2.2 ± 0.5g	3.6 ± 0.3h

Fluoride strip treatment significantly inhibited enamel demineralization. Calcium loss was the change, relative to the baseline, in the calcium content after treatment in the demineralizing solutions while calcium uptake was the change after treatment in the remineralizing solutions. The net value was the sum of calcium loss and calcium uptake.

^a–hThe net values having no statistically significant differences (n = 15) are identified with the same letter, whereas those having significant differences are represented with different letters.