Influence of Er,Cr:YSGG laser irradiation on enamel caries prevention
DOI: 10.1007/s10103-012-1056-9
Abstract
The
objective of this study was to evaluate the effects of
chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser irradiation
on the acid resistance of dental enamel. Forty human enamel
samples were divided into four groups. They were manually irradiated
with an Er,Cr:YSGG laser device (λ = 2.78 µm, 20 Hz, 20 s),
in a scanning mode, with and without water cooling, according
to the following parameters: Group 1: 0.25 W, 62.5 J/cm2, no water cooling; group 2: 0.25 W, 62.5 J/cm2, 5.0 ml/min; group 3: 0.5 W, 125 J/cm2, no water cooling; group 4: 0.5 W, 125 J/cm2,
5.0 ml/min. No airflow was used. Afterwards, the samples were submitted
to an acid challenge and assessed by cross-sectional
Knoop microhardness at different depths (20, 40, 60, 80, and
100 µm) from the outer enamel surface. Average values were obtained
for both irradiated and control areas in each sample and
they were compared to obtain a percentage of microhardness increase.
Data were analyzed by analysis of variance and Fisher’s
exact test (α = 5%). The percentage of microhardness increase observed
in group 1 (+23.58%) was similar to group 3 (+19.12%), but
higher than groups 2 (+3.61%) and 4 (10.9%) (p < 0.05). The comparison of the depths showed that the Er,Cr:YSGG laser acted in the superficial layers of the dental enamel.
The findings of the present study suggest that the energy densities of 62.5 and 125 J/cm2 were capable of increasing the acid resistance of human enamel. The presence of water during irradiation makes it difficult
to obtain an enamel surface more resistant to acids.
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