Effect of Nd: YAG laser-fluoride application sequence on enamel demineralization: a micro-CT in vitro study
7 affiliations
- 1Department of Clinical and Preventive Dentistry, Universidade Federal de Pernambuco, Recife, Brazil
- 2Department of Land Resource Science, University of Guelph, Guelph, Canada
- 3Department of Physics, Universidade Federal de Pernambuco, Recife, Brazil
- 4Department of Oral and Maxillofacial Pathology, Universidade de Pernambuco, Recife, Brazil
- 5Department of Stomatology, Universidade de São Paulo, São Paulo, Brazil
- 6Faculdade de Odontologia do Recife, Recife, Brazil
- 7Department of Dentistry, Universidade Estadual da Paraíba, Campina Grande, Brazil
Abstract
To evaluate, in an in vitro model, whether pulsed Nd: YAG laser irradiation combined with 5% sodium fluoride varnish inhibits bovine enamel demineralization more effectively than fluoride alone, and whether the order of application and the laser power influence the outcome. One hundred and ten bovine enamel specimens were randomly allocated to five groups: Control (C), Fluoride (F), Laser (L), Fluoride-then-Laser (FL), and Laser-then-Fluoride (LF). Irradiated groups received a pulsed Nd: YAG laser at 10 Hz and 300 µs at average powers of 0.5, 0.75, and 1.0 W, with 10 specimens per power subgroup. After treatment, specimens underwent a 48-hour chemical demineralization challenge. Surface loss, measured as lesion step-height in micrometres, and the difference in relative radiodensity between treated and protected enamel were quantified by micro-computed tomography. Data were compared by one-way ANOVA with Tukey’s post hoc test, α = 0.05. The control group showed the greatest surface loss, 89.8 ± 24.6 μm, and the largest radiodensity difference, 1756 ± 746 grayscale units. All treatments except FL0.5 significantly reduced surface loss relative to control. The Laser-then-Fluoride sequence produced the lowest surface loss at every power, from 11.2 to 15.1 μm, but these values did not differ significantly from fluoride alone, which yielded 33.8 ± 23.9 μm. Surface loss did not differ significantly among the three laser powers. The lowest radiodensity differences were recorded in LF1 and F, at 317 ± 401 and 376 ± 292 grayscale units, which did not differ significantly from each other. Applying the laser before fluoride varnish outperformed the reverse sequence, whereas laser power did not influence the outcome. Under the conditions of this in vitro model, the anti-demineralization effect of the best laser-assisted protocol was comparable to that of fluoride varnish alone. Whether laser pretreatment confers a measurable advantage in clinical conditions remains to be determined.
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BibTeX
@article{gomes2026effect,
title = {{Effect of Nd: YAG laser-fluoride application sequence on enamel demineralization: a micro-CT in vitro study}},
author = {Angelinne Ribeiro Angelo Gomes and Richard John Heck and Anderson Stevens Leonidas Gomes and Pamella Recco Alvares and Luiz Gustavo de Sousa Duda Júnior and Shamara Pinto Ferreira da Cruz and Ana Marly Araújo Maia and Luiz Alcino Monteiro Gueiros},
journal = {Lasers in Medical Science},
year = {2026},
month = oct,
doi = {10.1007/s10103-026-05080-3},
url = {https://doi.org/10.1007/s10103-026-05080-3},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Effect of Nd: YAG laser-fluoride application sequence on enamel demineralization: a micro-CT in vitro study
AU - Angelinne Ribeiro Angelo Gomes
AU - Richard John Heck
AU - Anderson Stevens Leonidas Gomes
AU - Pamella Recco Alvares
AU - Luiz Gustavo de Sousa Duda Júnior
AU - Shamara Pinto Ferreira da Cruz
AU - Ana Marly Araújo Maia
AU - Luiz Alcino Monteiro Gueiros
PY - 2026
DA - 2026/10/27
JO - Lasers in Medical Science
DO - 10.1007/s10103-026-05080-3
UR - https://doi.org/10.1007/s10103-026-05080-3
AB - To evaluate, in an in vitro model, whether pulsed Nd: YAG laser irradiation combined with 5% sodium fluoride varnish inhibits bovine enamel demineralization more effectively than fluoride alone, and whether the order of application and the laser power influence the outcome. One hundred and ten bovine enamel specimens were randomly allocated to five groups: Control (C), Fluoride (F), Laser (L), Fluoride-then-Laser (FL), and Laser-then-Fluoride (LF). Irradiated groups received a pulsed Nd: YAG laser at 10 Hz and 300 µs at average powers of 0.5, 0.75, and 1.0 W, with 10 specimens per power subgroup. After treatment, specimens underwent a 48-hour chemical demineralization challenge. Surface loss, measured as lesion step-height in micrometres, and the difference in relative radiodensity between treated and protected enamel were quantified by micro-computed tomography. Data were compared by one-way ANOVA with Tukey’s post hoc test, α = 0.05. The control group showed the greatest surface loss, 89.8 ± 24.6 μm, and the largest radiodensity difference, 1756 ± 746 grayscale units. All treatments except FL0.5 significantly reduced surface loss relative to control. The Laser-then-Fluoride sequence produced the lowest surface loss at every power, from 11.2 to 15.1 μm, but these values did not differ significantly from fluoride alone, which yielded 33.8 ± 23.9 μm. Surface loss did not differ significantly among the three laser powers. The lowest radiodensity differences were recorded in LF1 and F, at 317 ± 401 and 376 ± 292 grayscale units, which did not differ significantly from each other. Applying the laser before fluoride varnish outperformed the reverse sequence, whereas laser power did not influence the outcome. Under the conditions of this in vitro model, the anti-demineralization effect of the best laser-assisted protocol was comparable to that of fluoride varnish alone. Whether laser pretreatment confers a measurable advantage in clinical conditions remains to be determined.
SN - 0268-8921
SN - 1435-604X
ER -