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The successful clinical application of the Er:YAG-laser in dentistry is well known, documented by numerous published
studies. These lasers are flash lamp pumped systems and emit pulses of typically some 100 μs duration with energies of
up to 1 J. Pulse repetition rates can reach up to 100Hz, and mean powers are up to about 8W. As an alternative to these
laser systems recently a novel diode pumped Er:YAG laser system (Pantec Engineering AG) became available. This
laser can provide a pulse repetition rate up to 2kHz and a mean laser power up to 15W. The aim of the presented study is
to investigate the effect of this laser system on dental hard and soft tissue at various irradiation parameters, particular at
repetition rates more than 100 Hz.
At first an appropriate experimental set-up was realized with a beam delivery and focusing unit, a computer controlled
stepper unit with sample holder, and a shutter unit. The stepper unit allows to move the samples (dentin or enamel slides
of extracted human teeth, chicken breast, pig bone) with a defined velocity during irradiation by various laser
parameters. For rinsing the sample surface a water spray was also included. The laser produced grooves and cuts were
analyzed by light microscopy and laser scanning microscopy regarding to the ablation quality, geometry, ablation
efficacy, and thermal effects.
The grooves in dentin and enamel show a rough surface, typical for Er:YAG laser ablation. The craters are slightly cone
shaped with sharp edges on the surface. Water cooling is essential to prevent thermal injury. The ablation efficacy in
dentin is comparable to literature values of the flash lamp pumped Er:YAG laser. The cutting of bone and soft tissue is
excellent and appears superior to earlier results obtained with flash lamp pumped system. As a further advantage, the
broad range of repetition rates allows to widely vary the thermal side effects.
In conclusion, these first experiments with a diode pumped Er:YAG laser system on dental hard and soft tissue
demonstrate its ability for use in dentistry.
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