The exposition of nanoparticles caused by laser application in dental health care is an open
discussion. Based on the fact that nanoparticles can penetrate through the mucosa, the knowledge
about particle characteristics after irradiation with an USPL is of high importance. Therefore, the aim of
this study was to investigate the particle characteristics, especially the size of the ablated debris after
The irradiation was carried out with an USP Nd:YVO4 laser with a center wavelength of 1064 nm.
Based on the pulse duration of 8 ps and a pulse repetition rate of 500 kHz the laser emits an average
power of 9 W. The materials investigated were dental tissues and dental restorative materials
(composite and amalgam), ceramic and different metals (gold and aluminium). The samples were
irradiated with a power density in the order of 300 GW/cm2 at distances of 5, 10, 15, and 20 mm. The
debris was collected on an object plate. SEM pictures were used for analysis of the ablation debris.
Depending on the irradiated material, we observed different kinds of structures: vitreous, flocculent,
and pellet-like. The mean particle sizes were 10 x 10 up to 30 x 30 μm2. In addition, a cluster of ablated
matter (nanometer range) distributed over the whole irradiated area was found. With increasing
distances the cluster structure reduced from multi-layer to mono-layer clusters.
Particle sizes in the micrometer and nanometer range were found after irradiation with an USPL. The
nanoparticles create a cluster structure which is influenced by increasing distances.