In vivo Effects of a SnF2 Gel on Acid-softened Enamel

Abstract

The purpose of this investigation was to study the intra-oral rehardening of acid-softened enamel and fluoride uptake from SnF2 gel. Bovine enamel slabs were softened with 0.1 mol/L lactate buffer at pH 4.0 for 14 hrs and then mounted in a mandibular removable Hawley appliance. Control slabs were worn for 96 hrs by seven adult males whose teeth were brushed daily with a fluoride-free dentifrice. Test slabs were exposed once/day to 0.4% SnF2 gel. The gel was swabbed onto the slabs for one minute before being replaced in the mouth unrinsed. The natural dentition was brushed 4 X /day with a fluoride-free dentifrice. Microhardness testing was performed after intra-oral exposure (IOE) and after acid-resistance-testing (ART) following immersion in 0.01 mol/L lactate buffer for 24 hrs at pH of 4.0. Fluoride uptake was measured on separate controls, test slabs, and test slabs after ART, with 0.5 mol/L HClO4 etches of from 15 to 60 sec. The F content was measured with a F-ion-specific electrode and the phosphate content by spectrophotometry. Following IOE, microhardness recovery was 35.6% for control and 37.9% for test slabs, and control slabs retained 1.4% resistance to acid, as compared with 18.6% for the test slabs. The F content of control slabs was significantly less than that of SnF2-treated slabs from 5 to 60 micron in depth, and the F content of SnF2-treated slabs after ART was significantly less at depths of from 5 to 35 micron than that of SnF2-treated slabs not exposed to ART. Both control and SnF2 enamel slabs demonstrated rehardening after IOE, but only SnF2-treated enamel retained a significant fraction of that rehardening after ART.

Comparison of the Effects of Two Topical Fluoride Regimens on Demineralized Enamel in vivo

“…The early SnF2 agents (i.e., 8% SnF2 solutions) were effective in reducing enamel solubility (Muhler and van Huysen, 1947;Feller, 1974) and inhibiting bacterial growth (Tinanoff and Weeks, 1979), but such agents experienced disuse because of an unpleasant taste and frequent gastric distress following application. The current self-applied 0.4% SnF2 gels (1000 ppm F) represent a significant reduction in the F content (20-fold reduction compared with the 8% solution), offer an acceptable taste, and have demonstrated a limited capacity to remineralize enamel lesions (Clark et al, 1986).…”

Intra-oral Effects on Acid-softened Enamel of NaF Lozenges Administered in Divided Daily Doses

“…Two subjects (A and B), who demonstrated in previous studies their consistent ability for intra-oral rehardening of demineralized bovine enamel Clark et al, 1986a;Clark et al, 1986b), wore 16 acid-softened bovine enamel slabs for each period for controls, 1-mg F lozenges used ix/day, and 0.25-mg F lozenges used 4x/day for seven consecutive days, as described in previous paragraphs. Microhardness-testing was performed and IOE% and ART% calculated for determination of the more effective experimental regimen to be subsequently utilized in the expanded study using the eight subjects.…”

Effect of Zamzam Water on the Microhardness of Initial Carious Lesion of Permanent Teeth Enamel (An in vitro study)

“…Following application of 0.05% sodium fluoride, an increase in the microhardness was detected, statistically this increase was significant. This may indicate a remineralization of initial carious lesion, it is assumed that fluoride ions reacted with the hydroxyl appetite crystals and a new crystalline product was formed which is differ from the fluoroapetite (3,23) . This might cause the increase in the microhardness values seen in this study.…”