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Updated: Feb 4, 2026

Laser Micro-Irradiation to Study DNA Recruitment During S Phase
Published on: April 16, 2021
Randomized in situ study on the efficacy of CO2 laser irradiation in increasing enamel erosion resistance
K M Ramalho1, C P Eduardo2, N Heussen3
1Department of Stomatology, Integrated Clinic, School of Dentistry, University of São Paulo, São Paulo, Brazil.
Objectives:
The aim of this double-blind, randomized in situ study was to evaluate the erosion-preventive effect of a specific set of CO2 laser parameters, associated or not with fluoride.
Methods:
Two hundred forty bovine enamel blocks were prepared for individual palatal appliances (n = 6 samples/appliance). The study had four phases of 5 days each, with ten volunteers and the following treatments: CO2 laser irradiation (L), fluoride treatment (F), combined fluoride and laser treatment (FL), and no treatment, control (C). Laser irradiation was performed at 0.3 J/cm2 (5 μs/226 Hz/10.6 μm) and the fluoride gel contained AmF/NaF (12'500 ppm F-/pH = 4.8-6). For erosive demineralization, the appliances were immersed extra-orally in citric acid (0.05 M/20 min/pH = 2.3) twice daily. Analysis of enamel surface loss was done using a 3D-laser profilometer on 3 days. Additionally, fluoride uptake was quantified and scanning electron microscopies were done. Data were analyzed with repeated measures ANOVA and post hoc pairwise comparisons (α = 0.05).
Results:
At all analyzing days, both laser groups caused the lowest means of enamel loss, which were also statistically significant lower than C (p < 0.05). At day 5, FL means ± SD (33.6 ± 12.6 μm) were even significantly lower than all other groups (C 67.8 ± 15.4 μm; F 57.5 ± 20.3 μm; L 46.8 ± 14.5 μm). Significantly increased enamel fluoride uptake was observed for both fluoride-containing groups (p < 0.05) at day 1.
Conclusion:
Compared to the control, the CO2 laser irradiation with a specific set of laser parameters (0.3 J/cm2/5 μs/226 Hz) either alone or in combination with a fluoride gel (AmF/NaF) could significantly decrease enamel erosive loss up to 5 days in situ.
Clinical Relevance:
Combined CO2 laser-fluoride treatment has a significant anti-erosive effect.
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