Morphological and chemical changes of deciduous enamel produced by Er:YAG laser, fluoride, and combined treatment.
OBJECTIVE
The purpose of this study was to evaluate in vitro morphological and chemical changes on human deciduous enamel produced by Er:YAG laser irradiation, fluoride application, combined treatment, and acid dissolution.


BACKGROUND
Er:YAG laser has been proposed as a potential preventive dental caries strategy. There is scarce information regarding deciduous enamel.


METHODS
Eighty enamel samples were assigned to eight groups (n=10): G1, control; G2, G3, and G4, Er:YAG laser irradiation at 7.5, 12.7, and 39.8 J/cm(2), respectively; G5, fluoride application; G6, G7, and G8, irradiation at previous densities plus fluoride application. Morphology was evaluated by scanning electron microscopy, and chemical composition was determined by energy dispersive X-ray spectroscopy before treatment (BT), after treatment (AT), and after acid dissolution (AAD). One way and repeated measures analysis of variance (ANOVA) were used (p≤0.05).


RESULTS
Morphology of lased surfaces included craters, exposed prisms, fractures, and melting. No morphological modifications appeared after fluoride application, or AAD. Chemically, AT: C atomic percentage (at%) decreased in G3, G4, and G8; O at% decreased in G5-G8; F content was higher for G7; trace elements remained under 1.0 at%; Ca at % increased in G4, G7, and G8; there were increments in P at% in G4 and G8; and Ca/P increased in G4, G7, and G8. AAD: F at% dropped to 0.00 in G5-G8; and P at% increased in G7.


CONCLUSIONS
Morphological changes of Er:YAG irradiated enamel represented mild to severe damages. Conditions employed in this study are not recommended for deciduous caries prevention. Er:YAG energy density influenced chemical changes in enamel to enhance its structure. Acid dissolution removed fluoride from enamel surface.
1 Universidad Autónoma del Estado de México , Facultad de Odontología, Centro de Investigación y Estudios Avanzados en Odontología (CIEAO), Toluca, Estado de México, México .
Carmen M
CM
Zamudio-Ortega
Rosalía
R
Contreras-Bulnes
Rogelio J
RJ
Scougall-Vilchis
Raúl A
RA
Morales-Luckie
Oscar F
OF
Olea-Mejía
Laura E
LE
Rodríguez-Vilchis
María M
MM
García-Fabila
D003743:Dental Enamel / Q000737:chemistry* / Q000528:radiation effects* / Q000648:ultrastructure; D005459:Fluorides / Q000494:pharmacology*; D006801:Humans; D053844:Lasers, Solid-State; D008855:Microscopy, Electron, Scanning
D005459:Fluorides