Acid-etch interval and shear bond strength of Er,Cr:YSGG laser-prepared enamel and dentin

Abstract

The formation of a superficial layer of tiny flakes has been observed on teeth prepared by Erbium lasers. It has been suggested that removing this layer (mechanically or chemically) may increase the bond strength of the resin composite. The purpose of this study is to evaluate the effect of various etching times on bond strength of resin composite to enamel and dentin prepared by Er,Cr:YSGG laser. Sixty previously flattened human molars were irradiated for 10 s by an Er,Cr:YSGG laser. Enamel (E) specimens were etched with 37% H(3)PO(4) for 20, 40 or 60 s and dentin (D) specimens were etched for 15 or 30 s. All specimens were prepared for a standard shear bond strength (SBS) test (1 mm/min). Data were analyzed [ANOVA, Tukey post-hoc, a < 0.05)] and the failure mode was studied under SEM. Mean SBS+/-sd (MPa) for each group was 16.97 +/- 7.77 (E20s), 21.34 +/- 3.55 (E40s), 14.08 +/- 4.77 (E60s), 13.62 +/- 7.28 (D15s) and 13.15 +/- 6.25 (D30s). SBS for E40s was significantly higher than E60s (p = 0.023). No difference was noted between the dentin groups. SEM evaluation showed predominantly cohesive failure. Within the limits of this study, etching time significantly influenced the SBS of composite resin to laser-prepared enamel. SEM showed subsurface cracks, fissures, and deformities leading to predominantly cohesive failure in both enamel and dentin.

Effect of Er,Cr:YSGG laser surface conditioning on the adhesion of fiber- reinforced composite and zirconia intraradicular posts to the root dentin

“…The output power of Er,Cr:YSGG laser can vary from 0 to 6 W [37]. Various output values were evaluated for dental use ranging from 0.5 to 1 W, 3 to 4.5 W and 6 W [38,39]. In the present study, high output values were tested since the laser was applied to the post surfaces that were not in contact with dental tissues.…”

The effect of Er,Cr:YSGG irradiation on microtensile bond strength of composite resin restoration

“…Some studies 16,29,30) evaluating the influence of acid etching time on bond strength in dentin irradiated with Er,Cr:YSGG lasers used the etching time of 15 sec, the conventional etching time of dentin and 30 sec with 37% phosphoric acid. And the laser output of 3 W or 4 W was used in those studies, which was much higher than used in current study (0.25 W).…”

“…To overcome this problem, mechanical or chemical removing of laser-modified layer has been suggested [14][15][16] . Gutknrcht et al 14) and Carvalho et al 15) suggested additional acid-etching of the laser-prepared cavity.…”

“…Gutknrcht et al 14) and Carvalho et al 15) suggested additional acid-etching of the laser-prepared cavity. Also, Obeidi et al 16) found that adjunctive use of phosphoric acid following water-rinsing appeared to have eliminated the laser-modified layer and recommended longer etching time to obtain higher bond strength.…”

Effect of the Er, Cr: YSGG Laser Parameters on Shear Bond Strength and Microstructure on Human Dentin Surface

“…It has a 2780-nm wavelength and absorbed strongly by both water and hydroxyapatite. The sudden evaporation of bound water causes micro-explosions that blast away tiny particles of the tooth (Obeidi et al, 2010). Previous studies reported that irregularities and the crater-shaped appearance of ablated dentin was comparable to the dentine surface after acid etching, which might promote micromechanical interlocking between dental restorative materials and the tooth surface (Visuri et al, 1996;Armengol et al, 1999;Martínez-Insua et al, 2000;Carrieri et al, 2007;Gurgan et al, 2008).…”