334 CO2-Laser and Fluoride on Erosion Prevention of Previously Eroded Enamel

Thursday, March 22, 2012: 2 p.m. - 3:15 p.m.
Presentation Type: Poster Session
D. RIOS1, M.C. JORDÃO1, A.C. MAGALHÃES2, L. WANG3, M.A.A.M. MACHADO1, R.S. NAVARRO4, and H.M. HONÓRIO1, 1Department of Pediatric Dentistry, Orthodontics and Public Health, Bauru School of Dentistry - University of São Paulo, Bauru-SP, Brazil, 2Biological Sciences, Bauru School of Dentistry - University of São Paulo, Bauru-SP, Brazil, 3Operative Dentistry, Bauru School of Dentistry - University of São Paulo, Bauru-SP, Brazil, 4Restorative Dentistry, University of São Paulo, Sao Paulo, Brazil
Objectives: This in vitro study aimed to evaluate the effect of CO2 laser-irradiation and/or fluoride on sound and previously eroded enamel subjected to erosive cycling.


Sixty bovine enamel blocks were subjected to short-term acidic exposure by immersion in cola drink for 6 min, resulting in surface softening without tissue loss. Than 40 sound and 40 eroded enamel blocks were randomly and equally divided into 4 groups (n=10) according to treatment: C- untreated (control); CO- CO2 laser irradiation 28.6J/cm2; F- AmF (1% F) fluoride application; CO + F- CO2 laser irradiation and subsequent fluoride application. Laser irradiation was performed with at 10.6 µm wavelength, 5 µm pulse duration and 50 Hz frequency. During 5 days the erosive cycle was conducted by immersion of the blocks in cola drink for 2 min, followed by immersion in artificial saliva for 120 min. This procedure was consecutively repeated 4 times per day. The blocks were maintained in artificial saliva overnight. Enamel loss was measured profilometrically after initial group treatment and after 1 and 5 days of erosive challenge. The data were tested using two way ANOVA and Tukey’s test (p<0,05).

Results: After treatments no enamel loss was observed on the studied groups (< 0.1 µm). After one day of erosive cycling, only fluoride treatment, for sound enamel; and fluoride associated or not to laser irradiation, for eroded enamel; resulted in less enamel loss compared to control groups. On the fifth day only fluoride on sound enamel significantly differed from control, with a preventive effect. 


Based on the results, CO2 laser irradiation when associated to fluoride has a limited effect against erosion and fluoride still the most effective treatment for enamel prevention.

This abstract is based on research that was funded entirely or partially by an outside source: FAPESP (Proc. 2009/12326-2 and 2010/16159-0)

Keywords: Enamel, Erosion, Fluoride and Lasers