In vitro evaluation of CO2 laser (9.3 µm), combined with NaF or AmF/NaF/SnCl2, in controlling erosion on human dental enamel

Author(s)

Yael Engel

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Odontologia (FO/SDO)
• Defense date: 2020-08-04

Examining board members

Patricia Moreira de Freitas Costa e Silva; Luciane Hiramatsu Azevedo; Taís Scaramucci Forlin; Daniela Rios Honório

• Advisor: Patricia Moreira de Freitas Costa e Silva

Abstract

Considering the positive effects of high power lasers in preventing dental caries and the promising results regarding the reduction of enamel erosion, the purpose of this in vitro study was to evaluate the potential of a CO2 laser (9.3 µm), combined with NaF or AmF/NaF/SnCl2, in controlling erosion on dental enamel. One-hundred and twenty slabs of human enamel were selected and, after erosive-like lesion formation, randomly allocated into 12 treatment groups (n=10): W - negative control (no treatment); E - AmF/NaF/SnCl2 solution (500 ppm F- and 800 ppm Sn2+); R - NaF rinse (225 ppm F-); S - NaF slurry (5000 ppm F-); L1 - CO2 laser (0.69 W); L1+E - CO2 laser + AmF/NaF/SnCl2 solution; L1+R - CO2 laser + NaF rinse; L1+S - CO2 laser + NaF slurry; L2 - CO2 laser (0.58 W); L2+E - CO2 laser + AmF/NaF/SnCl2 solution; L2+R - CO2 laser + NaF rinse and L2+S - CO2 laser + NaF slurry. Samples were subjected to 10 days of erosive cycling through alternate immersions in 0,5% citric acid (pH 2.3, 2 minutes, 6x/day, at intervals of 1,5 h) and artificial saliva. Two CO2 irradiation parameters (9.3 µm) were tested (L1 and L2), followed by daily immersions in 5 ml of AmF/NaF/SnCl2 solution (E, L1+E and L2+E), or NaF rinse (R, L1+R and L2+R) or NaF slurry (S, L1+S and L2+S).Immediately after surface treatments, after 5 days of erosive cycling and at the end of the 10 days of erosive cycling, the superficial tissue loss was determined by non-contact optical profilometry (µm). Additionally, 36 samples (n=3) submitted to 10 days erosive cycling and 36 extras samples (n=3) submitted only to surface treatments were evaluated qualitatively by scanning electron microscopy. Surface wear data were submitted to normality and homoscedasticity tests, followed by analysis two-way ANOVA and Tukey post-hoc tests, at a significance level of 5%. There was no difference between groups after treatments. After 5 days of erosive cycling, E, L1+S, L2+E, L2+R and L2+S groups did not show statistical difference among them, having presented the lowest surface loss. After 10 days, groups treated with AmF/NaF/SnCl2 rinse (E, L1+E and L2+E) showed less surface loss, and in the L2+E group there was no statistically significant increase at the three time points. The CO2 laser (9.3 µm), in both parameters, was able to inhibit dental erosion when associated with NaF and AmF / NaF / SnCl2. (AU)

• FAPESP's process: 18/09716-2 - In vitro evaluation the potential of a CO2 laser (9.3 ¼m), associated or not with stannous fluoride or titanium tetrafluoride, in controlling erosion in human dental enamel
• Grantee: Yael Engel
• Support Opportunities: Scholarships in Brazil - Master