Avtor/Urednik		Majaron, Boris; Lukač, Matjaž; Šušterčič, Dušan; Funduk, Nenad; Skalerič, Uroš
Naslov		Threshold and efficiency analysis in Er:YAG laser ablation of hard dental tissue
Tip		članek
Vir		Proc - SPIE
Vol. in št.		Letnik 2933
Leto izdaje		1996
Obseg		str. 233-42
Jezik		eng
Abstrakt		Influence of pulselenght on mid-infrared laser ablation of hard dental tissue was studied experimentally by applying free-generated Er:YAG laser pulses with pulselengths from 50 micro s to 1 ms and different energies to dentin slices in vitro with no spray cooling. The results show that for pulselengths between 50 and 300 micro s, dentin ablation turns up abruptly at a well defined fluence value of approximately 4 J/cm2, which is independent of the pulselength. Similarly, volumes of the resulting craters as a function of laser fluence at these pulselengths follow nearly the same curve, which corresponds well to a model of laser beam screening by the ejected debris. However, with 1 ms long laser pulses, the ablation turns up at laser fluences above 4 J/cm2 only gradually, reaching differential ablation efficiency similar as in previous cases at fluence values several times higher than the ablation threshold value. An estimate of this "second threshold" fluence and the pulselengths at which it should in general be observed are derived from a simple model of heat diffusion and ablation front dynamics.
Deskriptorji		LASER SURGERY DENTIN ERBIUM YTTRIUM