Influence of the water content in dental enamel and dentin on ablation with erbium YAG and erbium YSGG lasers.

The theory of the ablation of dental hard tissue with erbium lasers is based on a process of thermomechanical interaction, which is explained by the absorption of the radiation in the water component of the tissue. The abrupt evaporation of the water is the cause of tissue fragments being blasted out of the tooth structure. The aim of this study is to examine the effect of the water contained in dental hard tissues on the efficiency of ablation. 192 specimens of both bovine dental enamel and bovine dentin are irradiated with an Er:YAG and an Er,Cr:YSGG laser. Half of the specimens are dehydrated beforehand. Irradiation is carried out in subgroups: without water spray and with water spray at flow rates of 0.8 and 3 mls. The ablated volume is determined following histological preparation. Only in dentin, and then only with irradiation with the Er:YAG laser, is the water contained in the tissue found to have a significant influence (p < 0.0001) on the ablated volume. The water content has no effect on the efficiency of laser ablation in any of the other test groups. In contrast, the externally supplied water always has a significant influence on the effectiveness of the ablation process.

[1]  J. Walsh,et al.  Infrared radiometry of dental enamel during Er:YAG and Er:YSGG laser irradiation. , 1996, Journal of biomedical optics.

[2]  Boris Majaron,et al.  Thermomechanical laser ablation of hard dental tissues: an overview of effects, regimes, and models , 1999, Photonics West - Biomedical Optics.

[3]  M L Wolbarsht,et al.  Erbium:YAG (2.94 mum) laser effects on dental tissues. , 1990, Journal of laser applications.

[4]  Daniel Fried,et al.  Mechanism of water augmentation during IR laser ablation of dental enamel , 2002, Lasers in surgery and medicine.

[5]  M. Wolbarsht,et al.  Wet versus dry enamel ablation by Er:YAG laser. , 1992, The Journal of prosthetic dentistry.

[6]  Steven R. Visuri,et al.  Caries inhibition potential of Er:YAG and Er:YSGG laser radiation , 1996, Photonics West.

[7]  Boris Majaron,et al.  Fiber-tip drilling of hard dental tissues with Er:YAG laser , 1998, Photonics West - Biomedical Optics.

[8]  Raimund Hibst,et al.  Experimental studies of the application of the Er:YAG laser on dental hard substances: I. Measurement of the ablation rate , 1989, Lasers in surgery and medicine.

[9]  A. Vogel,et al.  Mechanisms of pulsed laser ablation of biological tissues. , 2003, Chemical reviews.

[10]  Boris Majaron,et al.  Threshold and efficiency analysis in Er:YAG laser ablation of hard dental tissue , 1996, European Conference on Biomedical Optics.

[11]  G. M. Hale,et al.  Optical Constants of Water in the 200-nm to 200-microm Wavelength Region. , 1973, Applied optics.

[12]  R. Rockafellar.  The multiplier method of Hestenes and Powell applied to convex programming , 1973 .

[13]  Peter Rechmann,et al.  Changes in surface morphology of enamel after Er:YAG laser irradiation , 1998, Photonics West - Biomedical Optics.

[14]  E. Abt,et al.  Evaluation of thermal cooling mechanisms for laser application to teeth , 1993, Lasers in surgery and medicine.

[15]  R M Cothren,et al.  A model for thermal ablation of biological tissue using laser radiation , 1987, Lasers in surgery and medicine.

[16]  J. Walsh,et al.  Erbium laser ablation of dental hard tissue: Effect of water cooling , 1996, Lasers in surgery and medicine.

[17]  R. Franzen,et al.  The Ablation Threshold of Er:YAG and Er:YSGG Laser Radiation in Dental Enamel , 2002, Lasers in Medical Science.

[18]  Boris Majaron,et al.  Influence of water spray on Er:YAG ablation of hard dental tissues , 1997, European Conference on Biomedical Optics.

[19]  F. Duck.  Chapter 9 – Tissue Composition , 1990 .

[20]  K. Matsumoto,et al.  Effects of Er,Cr:YSGG laser irradiation in human enamel and dentin: ablation and morphological studies. , 1999, Journal of clinical laser medicine & surgery.

[21]  Raimund Hibst,et al.  Er:YAG laser for dentistry: basics, actual questions, and perspectives , 1994, Other Conferences.

[22]  K. Matsumoto,et al.  Morphological and atomic analytical studies on enamel and dentin irradiated by an erbium, chromium:YSGG laser. , 2000, Journal of clinical laser medicine & surgery.

[23]  G. Dibdin.  The water in human dental enamel and its diffusional exchange measured by clearance of tritiated water from enamel slabs of varying thickness. , 1993, Caries research.

[24]  Martin Frenz,et al.  Mechanism of channel propagation in water by pulsed erbium laser radiation , 1994, Other Conferences.

[25]  Martin Frenz,et al.  Dynamics of laser-induced channel formation in water and influence of pulse duration on the ablation of biotissue under water with pulsed erbium-laser radiation , 1994 .

[26]  Daniel Fried,et al.  IR laser ablation of dental enamel , 2000, Photonics West - Biomedical Optics.

[27]  Terence A. King,et al.  Effects of a surface water film on the interaction of Er:YAG radiation with dental hard tissues in vitro , 1996, European Conference on Biomedical Optics.

[28]  D. W. Holcomb,et al.  Thermal decomposition of human tooth enamel , 2006, Calcified Tissue International.