ISSN 2756-3421
African Journal of Dentistry ISSN 3216-0216 Vol. 7 (1), pp. 001-007, January, 2019. © International Scholars Journals
Full Length Research Paper
In vitro evaluation of eroded enamel treated with fluoride and a prospective tricalcium phosphate agent
Robert L. Karlinsey1*, Allen C. Mackey1, Emily R. Walker1, Katherine E. Frederick1 and Christabel X. Fowler2
1Indiana Nanotech, Indianapolis, IN, United States of America.
2GlaxoSmithKline, Weybridge, United Kingdom.
Accepted 23 December 2018
Abstract
The anti-erosion effects of 225 ppm fluoride plus an innovative form of tricalcium phosphate (TCP-Si-Ur) relative to 225 ppm fluoride were investigated using a pH cycling model comprising treatment, saliva and acid challenge periods. Polished bovine enamel specimens were initially softened in 1% citric acid (pH = 3.8) and stratified (N = 10) into the following groups according to their Vickers microhardness: water, 225 ppm fluoride and 225 ppm fluoride containing 20, 40, or 80 ppm TCP-Si-Ur. The cycling regimen consisted of three two-minute treatment periods and five two-minute acid challenges (1% citric acid, pH = 3.8) per day for a total of 20 days. Surface microhardness measurements were made at 10 and 20 days. After 10 days, statistical differences (t-tests, p < 0.05) only existed between water and each of the four fluoride-containing groups. After 20 days, significant differences were observed among the fluoride-containing groups, with fluoride plus 20 ppm TCP-Si-Ur providing significant surface strengthening relative to fluoride alone. Cross-sectional microhardness measurements revealed distinctly different strength profiles and infrared spectroscopy was employed to probe possible changes in enamel microstructure. Collectively, our results indicate a synergistic effect can be produced when TCP-Si-Ur is combined with fluoride and administered to eroded enamel.
Key words: Dental erosion, fluoride, tricalcium phosphate, TCP-Si-Ur, microhardness, IR spectroscopy, pH cycling, remineralization.