Journal of Dental Research, Vol 71, 443-447, Copyright © 1992 by International & American Associations for Dental Research Online Journals
Effect of a two-solution fluoride mouthrinse on remineralization of enamel lesions in vitro
L. C. Chow, S. Takagi and S. Shih
American Dental Association Health Foundation, Paffenbarger Research Center, National Institute of Standards and Technology, Gaithersburg, Maryland 20899.
A previous study showed that a two-solution fluoride (F) rinse deposited
significantly more loosely-bound F on the tooth surface than did a sodium
fluoride (NaF) rinse with the same F concentration (12 mmol/L). In the
present study, this experimental rinse was evaluated for its ability to
cause remineralization of enamel lesions in an in vitro pH-cycling model.
Caries-like lesions were formed in the enamel of extracted human molars by
means of a pH 4 demineralizing solution. Fifty-one approximately
120-microns-thick sections containing lesions were randomly divided into
(1) control, (2) NaF rinse, and (3) two-solution F rinse groups. With the
cut surfaces protected, the control samples were immersed in a pH 7
remineralizing solution for 12 days, and twice daily the sections were also
exposed to a pH 4 demineralizing solution for 30 min. Samples in the NaF
group received an additional one-minute rinse with a NaF (12 mmol/L)
solution twice daily. Samples in the two-solution rinse group received the
rinse treatment with a 12 mmol/L F solution prepared by combination of a
Na2SiF6 and phosphate-containing solution with a calcium solution just
before use. The mineral contents of the lesions were assessed by
quantitative microradiography. The results showed that (1) no significant
de- or remineralization was detected in the controls; (2) a 46% decrease in
mineral loss (delta Z) of the lesion was produced by the NaF rinses; and
(3) a 94% decrease in delta Z and a 20-microns-thick, mineral-dense
surface-coating were produced by the two-solution F rinse treatment.
