Microhardness and morphological changes induced by Nd:Yag laser on dental enamel: an in vitro study.
The aim of this work was a scanning electron microscopy (SEM) evaluation of the hardness and morphological changes of enamel irradiated by neodymium: yttrium aluminium garnet (Nd:YAG) laser with different energy levels. Twenty-eight human teeth samples were divided into 4 groups: control, where enamel surface was not lased, and 3 test treated with 3 different levels of energy power 0.6, 1.2 and 2.4 Watt, respectively. In each group, 5 samples underwent Vickers micro-hardness test and 2 samples were processed for SEM. No significant differences between treated and non treated samples were found by micro-hardness test. However, by SEM, test samples showed a rougher enamel surface than control. Specifically, the 0.6 Watt treated samples showed vertical scratches and glass-like areas, while in the other 2 groups enamel surface was covered by craters and cracks. These findings suggest that enamel should be lased at a low energy level to preserve its integrity and reduce demineralization, and thus for dental caries prevention purposes; while high energy level creates a retentive surface suitable for sealant or composite anchorage.
Bedini
Rossella
R
Dipartimento di Tecnologie e Salute, Istituto Superiore di Sanità, Rome, Italy. rossella.bedini@iss.it
Manzon
Licia
L
Fratto
Giovanni
G
Pecci
Raffaella
R
D003743:Dental Enamel / Q000473:pathology* / Q000528:radiation effects*; D006245:Hardness Tests; D006801:Humans; D066298:In Vitro Techniques; D053844:Lasers, Solid-State; D008855:Microscopy, Electron, Scanning; D011829:Radiation Dosage