Acid resistance of erbium-doped yttrium aluminum garnet laser-treated and phosphoric acid-etched enamels.

OBJECTIVE To compare the effects of erbium-doped yttrium aluminum garnet (Er:YAG) laser ablation and of phosphoric acid etching on the in vitro acid resistance of bovine enamel. MATERIALS AND METHODS Teeth were polished to make the surface flat. The polished enamel was either etched with 37% phosphoric acid for 30 seconds or ablated with a single 33 J/cm2 pulse from an Er:YAG laser. The control specimens were free from acid etching and laser ablation. Changes in crystal structure, dissolved mineral (calcium [Ca] and phosphorus [P]) contents, and calcium distribution in the enamel subsurface after a pH-cycling process were evaluated. RESULTS After laser treatment, poor crystal structures improved without forming any new phases, such as tricalcium phosphates. Among the tested enamels, dissolved mineral contents were significantly different (P < .05). Er:YAG laser-treated enamels had the lowest mineral dissolution (Ca, 13.78 ppm; P, 6.33 ppm), whereas phosphoric acid-etched enamels had the highest (Ca, 15.90 ppm; P, 7.33 ppm). The reduction rate and reduced depth of calcium content along the subsurface were lowest in Er:YAG laser-treated enamels. CONCLUSION The Er:YAG laser-treated enamels are more acid resistant to acid attack than phosphoric acid-etched enamels.

[1]  R. Prout,et al.  Lipid analysis of rat enamel and dentine. , 1973, Archives of oral biology.

[2]  P J Brockhurst,et al.  Bonding of resin composite to carbon dioxide laser-modified human enamel. , 1994, Dental materials : official publication of the Academy of Dental Materials.

[3]  Daniel Fried,et al.  Rational choice of laser conditions for inhibition of caries progression , 1995, Photonics West.

[4]  S. Kuroda,et al.  Compositional, structural, and phase changes inin vitro laser-irradiated human tooth enamel , 1984, Calcified Tissue International.

[5]  M. Swartz,et al.  An Adhesive Dental Restorative Material , 1971, Journal of dental research.

[6]  N. Gutknecht,et al.  Calcium solubility of dental enamel following sub‐ablative Er:YAG and Er:YSGG laser irradiation in vitro , 2002, Lasers in surgery and medicine.

[7]  Daniel Fried,et al.  Optical properties of dental enamel at 9 to 11 um derived from time-resolved radiometry , 1997, Photonics West - Biomedical Optics.

[8]  T. Eguro,et al.  Comparison of the bond strength of composite resin to Er:YAG laser irradiated human enamel pre‐treated with various methods In Vitro , 2002, Lasers in surgery and medicine.

[9]  R. Prout,et al.  Fatty acid composition of neutral lipids and phospholipids of enamel and dentine from human molars. , 1974, Archives of oral biology.

[10]  W. E. Moody,et al.  Thermal Analysis of Human Dental Enamel , 1974 .

[11]  S. Kuroda,et al.  Changes in heated and in laser-irradiated human tooth enamel and their probable effects on solubility , 1986, Calcified Tissue International.

[12]  R. L. Cooley,et al.  Evaluation of a phosphonate BIS-GMA resin as a bracket adhesive. , 1991, Quintessence International.

[13]  M. Buonocore.  A Simple Method of Increasing the Adhesion of Acrylic Filling Materials to Enamel Surfaces , 1955, Journal of dental research.

[14]  D. Retief,et al.  Tensile and shear strengths of bonded and rebonded orthodontic attachments. , 1981, American journal of orthodontics.

[15]  A. Blinkhorn,et al.  A comparison of surface roughness and composite/enamel bond strength of human enamel following the application of the Nd:YAG laser and etching with phosphoric acid. , 1997, Dental materials : official publication of the Academy of Dental Materials.

[16]  T. H. Jordan,et al.  Effects of Low-energy CO2 Laser Irradiation and the Organic Matrix on Inhibition of Enamel Demineralization , 2000, Journal of dental research.

[17]  L. Legler,et al.  Effects of phosphoric acid concentration and etch duration on enamel depth of etch: an in vitro study. , 1990, American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics.

[18]  H. Busscher,et al.  A laboratory evaluation of three etching solutions. , 1986, Dental materials : official publication of the Academy of Dental Materials.

[19]  A. Aoki,et al.  Comparison between Er:YAG Laser and Conventional Technique for Root Caries Treatment in vitro , 1998, Journal of dental research.

[20]  U. Santana-Penín,et al.  Differences in bonding to acid-etched or Er:YAG-laser-treated enamel and dentin surfaces. , 2000, The Journal of prosthetic dentistry.

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

[22]  Daniel Fried,et al.  Effect of pulse duration and repetition rate on CO2 laser inhibition of caries progression , 1996, Photonics West.

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

[24]  Daniel Fried,et al.  Optical properties of dental enamel in the mid-IR determined by pulsed photothermal radiometry , 1999 .

[25]  N. Nakabayashi,et al.  Preparation of an effective light-cured bonding agent for orthodontic application. , 1997, Dental materials : official publication of the Academy of Dental Materials.

[26]  W. E. Brown,et al.  Infra-red spectra of hydroxyapatite, octacalcium phosphate and pyrolysed octacalcium phosphate. , 1966, Archives of oral biology.

[27]  S. Uşümez,et al.  Laser etching of enamel for direct bonding with an Er,Cr:YSGG hydrokinetic laser system. , 2002, American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics.

[28]  J L Gilbert,et al.  Shear Strength of Composite Bonded to Er:YAG Laser-prepared Dentin , 1996, Journal of dental research.

[29]  R. Prout,et al.  Lipid analysis of human enamel and dentine. , 1974, Archives of oral biology.

[30]  Dudley A. Williams,et al.  Lambert Absorption Coefficients of Water in the Infrared , 1971 .

[31]  K. Sato.  Relation between acid dissolution and histological alteration of heated tooth enamel. , 1983, Caries research.

[32]  G L Powell,et al.  Dentistry for the 21st century? Erbium:YAG laser for teeth. , 1997, Journal of the American Dental Association.

[33]  V. Pedraza Muriel,et al.  Comparing the tensile strength of brackets adhered to laser-etched enamel vs. acid-etched enamel. , 1997, Journal of the American Dental Association.

[34]  T Oho,et al.  A possible mechanism of acquired acid resistance of human dental enamel by laser irradiation. , 1990, Caries research.