Etching Enamel for Orthodontics with an Erbium, Chromium:Yttrium-Scandium-Gallium-Garnet Laser System

Abstract

Objective: To test the shear bond strength, surface characteristics, and fracture mode of brackets that are bonded to enamel etched with an erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser operated at different power outputs: 0.5 W, 1 W, and 2 W. Materials and Methods: Human premolars that had been extracted for orthodontic purposes were used. Enamel was etched with an Er,Cr:YSGG laser system operated at one of three power outputs or with orthophosphoric acid. Results: The shear bond strength associated with the 0.5-W laser irradiation was significantly less than the strengths obtained with the other irradiations. Both the 1-W and 2-W laser irradiations were capable of etching enamel in the same manner. This finding was confirmed by scanning electron microscopy examination. The evaluation of adhesive-remnant-index scores demonstrated no statistically significant difference in bond failure site among the groups, except for the 0.5-W laser-etched group. Generally, more adhesive was left on the enamel surface with laser irradiation than with acid etching. Conclusion:The mean shear bond strength and enamel surface etching obtained with an Er,Cr: YSGG laser (operated at 1 W or 2 W for 15 seconds) is comparable to that obtained with acid etching.

Comparison of the Effect of Three Mechanical Surface Treatments on the Repair Bond Strength of a Laboratory Composite

“…In contrast to the bur, which wears out substrates such as restorative materials and produces a smear layer, laser ablates the restorative materials without smear layer formation, 10,12 and several studies have shown that Er, Cr: YSGG laser does not produce any smear layer. 8,12,19 Formation of a smear layer makes bonding of the adhesive resins difficult because of its low surface energy. 20 Regarding the AFM data, although there were no significant differences in surface roughness values between laser-treated and bur-ground groups, in the laser-treated group there was a significant increase in surface area compared with the burground group.…”

Er:YAG Laser for Brackets Bonding: A SEM Study after Debonding

“…With the recent introduction of erbium-doped yttrium aluminum garnet (Er:YAG) laser in dentistry for the ablation of hard tissues, including enamel and dentin, laser enamel preparation has been proposed as an alternative to phosphoric acid etching [7–9]. The Er:YAG laser can effectively modify enamel and dentin surfaces because of its 2.94 mm wavelength emission, which coincides with the main absorption band of water and OH− groups in hydroxyapatite [10].…”

Comparative Evaluation of Shear Bond Strength of Orthodontic Brackets using Laser Etching and Two Conventional Etching Techniques: An in vitro Study

“…The ablation of tooth structure is achieved, via a thermomechanical interaction and, since the tissue is not completely vaporised, but only disintegrated into fragments, the majority of incident radiation is consumed in the ablation process, leaving very little residual energy for adverse thermal interactions with the pulp tissue and surrounding soft and/or hard structures. 8,20 Moreover, Er:YAG laser etching is painless and does not involve either vibration or heat, and the easy handling of the apparatus makes this treatment highly attractive for routine clinical use. 13 Also, this laser can be used in wet conditions and the water-cooled system does not cause any untoward thermal effects on the tooth pulp.…”