Abstract

BEDINI, Rossella; MANZON, Licia; FRATTO, Giovanni  and  PECCI, Raffaella. Microhardness and morphological changes induced by Nd: Yag laser on dental enamel: an in vitro study. Ann. Ist. Super. Sanità [online]. 2010, vol.46, n.2, pp. 168-172. ISSN 0021-2571.  http://dx.doi.org/10.4415/ANN_10_02_10.

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 microhardness 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.

Keywords : energy power; micro-hardness; Nd:YAG laser; microscopy.