The Synergistic Effect of Fluoride and Laser Radiation for the Inhibition of Demineralization of Enamel Surfaces
Lasers have been used to demonstrate that the chemical composition of enamel surfaces can be changed to provide for more resistance to acid demineralization. CO2 lasers tuned to a wavelength of 9.3 µm can be used to efficiently convert the carbonated hydroxyapatite (HAP) of enamel to a much more acid resistant purer phase HAP. For more protection, fluoride application to HAP yields fluoroapatite (FAP); which is an even more impervious substance against demineralization. Studies have shown that there is a synergistic effect of the laser treatments with fluoride application and inhibition close to 100%. Previous studies showed that a new CO2 laser could be used to create highly uniform surface treatments of enamel surfaces and the peripheral zones were identified to have increased acid resistance. We postulate that a combination of fluoride and laser treatment will impart higher inhibition to acid attack.
The conclusion of this experiment can be summarized into three points. First, there was no significant effect of fluoride on either laser treated or non-laser treated surfaces. Next, the non-melted lesion zones were as protective to the enamel surface as the melted lesion zones as seen in the low integrated reflectivity for both the low energy and high energy “Laser” bars. Lastly, PS-OCT 2D protection images of integrated reflectivity are well suited to non-destructive assessment of caries inhibition.
We would like to thank Nai-Yuan N Chang, Rhett Berg and William A Fried for their contributions and acknowledge the support of UCSF School of Dentistry and NIH/NIDCR grants R01-DE014698, R01- DE017869, R01-DE019631.