Influence of fluoride concentration and ethanol pre-treatment on the reduction of the acid susceptibility of enamel.
OBJECTIVE
To determine the association between KOH-soluble and structurally bound fluoride uptake and the erosion resistance of enamel, respectively. Additionally, the effect of enamel pre-treatment with ethanol before fluoridation was assessed.


METHODS
Sixty bovine incisors (4 specimens/tooth) were randomly allocated to six groups (A-F). Samples 1 and 2 remained untreated, serving as control at baseline. Pre-treatment of the samples was performed for 5 min with 99% ethanol (groups A, B and C) or physiologic saline (groups D, E and F). Samples 3 and 4 were treated either with 0.5% (groups A and D), 1.0% (groups B and E) or 1.5% (groups C and F) fluoride solution. In samples 1 and 3, uptake of KOH-soluble and structurally bound fluoride was determined. Samples 2 and 4 were used for the determination of acid susceptibility by immersion in 1 ml HCl for 30s. Calcium release into HCl was assessed by atomic absorption spectroscopy. Differences between the groups were calculated by unpaired t-tests (p<0.05).


RESULTS
Mode of pre-treatment showed no influence on fluoride acquisition. KOH-soluble and structurally fluoride uptake increased with increasing fluoride concentrations. Highest acid resistance was observed after treatment with 1% fluoride solution for both kinds of pre-treatment followed by 1.5% and 0.5% fluoride solution.


CONCLUSIONS
Dose-dependency was observed for enamel fluoride acquisition but not for acid resistance.
Wegehaupt
Florian J
FJ
Clinic for Preventive Dentistry, Periodontology and Cariology, University of Zürich, Plattenstrasse 11, CH-8032 Zürich, Switzerland. florian.wegehaupt@zzmk.uzh.ch
Solt
Barbara
B
Sener
Beatrice
B
Wiegand
Annette
A
Schmidlin
Patrick R
PR
Attin
Thomas
T
D000818:Animals; D002118:Calcium / Q000032:analysis; D002124:Calcium Fluoride / Q000493:pharmacokinetics; D002327:Cariostatic Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics; D002417:Cattle; D003733:Dental Caries Susceptibility / Q000187:drug effects; D003743:Dental Enamel / Q000187:drug effects* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000494:pharmacology*; D005459:Fluorides / Q000008:administration & dosage* / Q000493:pharmacokinetics; D006851:Hydrochloric Acid / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D006878:Hydroxides / Q000493:pharmacokinetics; D008422:Materials Testing; D017680:Potassium Compounds / Q000493:pharmacokinetics; D011897:Random Allocation; D012995:Solubility; D012997:Solvents / Q000494:pharmacology*; D013054:Spectrophotometry, Atomic; D013324:Strontium / Q000494:pharmacology
D002327:Cariostatic Agents; D006878:Hydroxides; D017680:Potassium Compounds; D012997:Solvents; D000431:Ethanol; C025700:strontium chloride; D002124:Calcium Fluoride; D005459:Fluorides; D006851:Hydrochloric Acid; D002118:Calcium; C029943:potassium hydroxide; D013324:Strontium