In vitro evaluation of enamel demineralization after Er:YAG and Nd:YAG laser irradiation on primary teeth.
OBJECTIVE
This in vitro study evaluated the influence of both Er:YAG and Nd:YAG laser irradiation on deciduous enamel demineralization.


BACKGROUND
Although there are still few studies on the use of the high-intensity laser for caries prevention in deciduous teeth, it is believed that its use on the dental structure can lead to a more acid-resistant surface.


METHODS
Forty enamel samples obtained from 22 deciduous first molar teeth were ground and randomly divided into four groups (n = 10): group 1 (G1), no treatment (negative control); G2, fluoride (positive control); G3, Er:YAG laser (2 Hz, 60 mJ, 40.3 J/cm(2)); G4, Nd:YAG laser (80 mJ, 10 Hz, 0.8 W). After the surface treatment, the samples were submitted to an acid challenge that consisted of a 5-day immersion in demineralizing (3 h) and remineralizing solution (21 h). Next, a microhardness test was preformed.


RESULTS
Analysis of variance (ANOVA) and Student Newman Keuls tests were performed (alpha = 5%). The percentage of lesion inhibition for each group was as follows: G2, 59.4%; G3, 35.7%; and G4, 40.4%. As regards the percentage loss of mineral volume, there was no statistical difference between groups G2 (444.37 +/- 146.42) and G3 (441.81 +/- 207.08) when compared with group G1 (281.03 +/- 134.57). All experimental groups presented a lower mineral loss compared with the non-irradiated samples (G4).


CONCLUSIONS
The findings of the present study revealed that both Nd:YAG and Er:YAG lasers can be an alternative tool for enhancing deciduous enamel acid resistance.
Castellan
Carina S
CS
Special Laboratory of Lasers in Dentistry, University of São Paulo (USP), São Paulo, Brazil.
Luiz
Ana Claudia
AC
Bezinelli
Leticia M
LM
Lopes
Roberta M G
RM
Mendes
Fausto M
FM
De P Eduardo
Carlos
C
De Freitas
Patricia M
PM
D003733:Dental Caries Susceptibility / Q000528:radiation effects; D003743:Dental Enamel / Q000528:radiation effects*; D006801:Humans; D007834:Lasers; D008963:Molar; D017001:Tooth Demineralization / Q000517:prevention & control*; D014094:Tooth, Deciduous / Q000528:radiation effects*