Shear bond strength and SEM morphology evaluation of different dental adhesives to enamel prepared with ER:YAG laser

Abstract

Context:Early observations of enamel surfaces prepared by erbium lasers motivated clinicians to use laser as an alternative to chemical etching.Aims:Evaluate shear bond strength (SBS) values of different dental adhesives on Erbium:Yttrium Aluminum Garnet (Er:YAG) laser prepared enamel and to evaluate possible etching patterns correlations between dental adhesives and SBS values.Subjects and Methods:One hundred bovine incisors were randomly assigned to SBS tests on enamel (n = 15) and to enamel morphology analysis (n = 5) after Er:YAG laser preparation as follows: Group I – 37% phosphoric acid (PA)+ ExciTE®; Group II – ExciTE®; Group III – AdheSE® self-etching; Group IV – FuturaBond® no-rinse. NR; Group V – Xeno® V. Teeth were treated with the adhesive systems and subjected to thermal cycling. SBS were performed in a universal testing machine at 5 mm/min.Statistical Analysis Used:One-way ANOVA and post-hoc tests (P < 0.05). For the morphology evaluation, specimens were immersed in Ethylenediamine tetraacetic acid (EDTA) and the etching pattern analyzed under Scanning Electron Microscope (SEM).Results:Mean bond strengths were Group I – 47.17 ± 1.61 MPa (type I etching pattern); Group II – 32.56 ± 1.64 MPa, Group III – 29.10 ± 1.34 MPa, Group IV – 23.32 ± 1.53 MPa (type III etching pattern); Group V – 24.43 MPa ± 1.55 (type II etching pattern).Conclusions:Different adhesive systems yielded significantly different SBSs. Acid etching significantly increased the adhesion in laser treated enamel. No differences in SBS values were obtained between AdheSE® and ExciTE® without condition with PA. FuturaBond® NR and Xeno® V showed similar SBS, which was lower in comparison to the others adhesives. No correlation between enamel surface morphology and SBS values was observed, except when PA was used.

The Effect of Energy Densities on the Shear Bond Strength of Self-Adhering Flowable Composite to Er:YAG Pretreated Dentin

“…Yet, results showed that the absence of smear layer formation during dentin preparation by Er:YAG laser did not improve the adhesion values of self-etching adhesive systems [22, 23]. Nevertheless, Yazici et al have proven that dentin prepared with Er:YAG laser might improve bonding effectiveness to dentin [10, 19, 24, 25], similar to using phosphoric acid prior to applying SACs [25–27]. However, some other studies have reported opposite results; studies showed that laser irradiation weakens the bond strength of the adhesive [28] and that conventional etching with 35% phosphoric acid yielded significantly higher bond strength values compared to thermal etching with the Er:YAG laser [29].…”

Comparison on Surface Roughness and Its Effect on Bonding between Conventional Bur and Laser Cut Cavities: An in vitro Study

“…7 Er,Cr:YSGG lasers are group of Erbium laser systems, that operates at a wavelength of 2.780 µm. 8 Erbium lasers produced similar surface to that of conventional phosphoric acid etching. 9 Erbium lasers with appropriate parameters selectively removes hydroxyapatite crystals from enamel producing surface irregularities that could enhance the micromechanical retention.…”

“…28 Ability of hard tissue removal without smear layer production has brought lasers into modern dentistry replacing these conventional burs. 8,29 Among various lasers, Erbium lasers (high-intensity lasers) are the most efficient and safest system of lasers, showing similarities to acid-etched enamel. 8,29 Er:Cr:YSGG lasers cut dental hard tissue with the help of its laser-powered hydrokinetic system at infrared wavelength of 2.7 to 3 µm.…”

“…8,29 Among various lasers, Erbium lasers (high-intensity lasers) are the most efficient and safest system of lasers, showing similarities to acid-etched enamel. 8,29 Er:Cr:YSGG lasers cut dental hard tissue with the help of its laser-powered hydrokinetic system at infrared wavelength of 2.7 to 3 µm. 30 Microexplosions during laser ablation produces imbricate-patterned surface with an evidently rough aspect without smear layer production.…”

Comparative Study of Acid Etching on Dental Enamel

“…When a coronary lesion is restored, one of the working principles to take into account is to use materials adhering to the dental surfaces. This avoids the phenomenon of marginal infiltration (percolation), as well as the onset of dentinal hypersensitivity or postoperative pain [3]. For this reason, in restorative dentistr y practice, the mere juxtaposition of a filling material in a cavity is no longer accepted.…”