The Journal of Oral Laser Applications
J Oral Laser Applications 10 (2010), No. 4     14. June 2011
J Oral Laser Applications 10 (2010), No. 2-3  (20.12.2010)

Page 117-124

Surface and Mineral Changes in Enamel when Treated with Acidulated Phosphate Fluoride Gel (APF) and CO2 Laser
Kumar, S. Sathya / Mohan, Ajit George / Kumar, N. Ravi / Kulandaivelu, T. Arun / Mahalaxmi, S.
Purpose: To compare in vitro the surface and mineral changes of enamel treated with acidulated phosphate fluoride gel (APF), CO2 laser, and a combination of both.
Materials and Methods: Forty extracted maxillary single-rooted teeth were randomly selected. Roots were resected and teeth were divided into 4 groups (n = 10). Group 1: control; group 2: APF gel applied; group 3: irradiated with CO2 laser; group 4: irradiated with CO2 laser and APF gel applied. A single application of APF gel (pH 3.5) was performed using a brush for 4 min. A pulsed CO2 laser with 10.6 µm wavelength was used with the following parameters:1 W, 50-µs pulse duration, 1-Hz repetition rate, and a 0.8-mm beam diameter. X-ray diffraction (XRD) analysis of all specimens was performed to determine the mineral changes, and surface changes were compared using SEM.
Results: XRD analysis of groups 1 and 2 showed only the presence of hydroxyapatite, whereas group 3, which was irradiated with CO2 laser, showed the presence of hydroxyapatite along with calcium hydrogen phosphate. Group 4 showed the presence of fluorapatite along with hydroxyapatite. SEM analysis revealed more fluoride retention in group 4 than in all the other groups. The SEM images confirm that fluoride application after CO2 laser irradiation presented a surface with fewer craters than the surface irradiated with CO2 alone.The XRD analysis revealed the presence of fluorapatite in groups treated with CO2 and APF gel, which was not to be seen in any other groups.
Conclusion: The combination of laser and fluoride treatment showed increased fluoride uptake, with the formation of fluorapatite. The adjunct use of these two treatments may be effective in preventing caries.

Keywords: APF, fluoride, hydroxyapatite, fluorapatite, laser, enamel, acid resistance