Journal of Dental Research, Vol 67, 954-958, Copyright © 1988 by International & American Associations for Dental Research Online Journals
Comparison of the effects of two topical fluoride regimens on demineralized enamel in vivo
J. W. Clark, R. E. Corpron, F. G. More, J. W. Easton, D. F. Merrill and C. J. Kowalski
Department of Pediatric Dentistry, School of Dentistry, University of Michigan, Ann Arbor 48109.
The purpose of this investigation was to study the intra-oral
remineralization of acid-softened enamel by a NaF dentifrice compared with
that from a combination of topical F agents. Bovine enamel slabs were
demineralized with 0.1 mol/L lactic acid at pH 4.0 for 14 hr and then
mounted in a removable mandibular appliance. Control slabs were worn for 96
hr by seven adult males who brushed daily with a F-free dentifrice. Test
slabs were brushed with a NaF dentifrice 4 x/day or with the same
dentifrice 4 x/day and a 0.02% APF mouthrinse and a 0.4% SnF2 gel which
were applied once/day for three days. The natural dentition was also
brushed with the NaF dentifrice during both test periods. Microhardness
testing was performed on sound enamel, and after acid-softening, intra-oral
exposure (IOE), and acid resistance testing (ART) in 0.01 mol/L lactic acid
at pH 4.0 for 24 hr. Control and test slabs were etched with 0.5 mol/L
HC1O4 for from 15 to 60 sec. The F content was measured with a F electrode
and PO4 by spectrophotometry. Contact microradiography and image analyses
were performed on control and test slabs so that changes in mineral content
resulting from treatment could be assessed. Both test groups were
significantly harder after both IOE and ART than were controls, but no
differences appeared between the effects of the two test groups. The F
content of control slabs was significantly less than that of both test
groups, and the combination-treated slabs showed greater F than did the
dentifrice-treated slabs.(ABSTRACT TRUNCATED AT 250 WORDS)
