Evaluation of Shear Bond Strength (SBS) of Orthodontic Brackets bonded to Lithium Disilicate glass-ceramics (E-Max) following Etching with Hydrofluoric Acid (HF) versus Er:YAG Laser and Er:Cr:YSGG Laser

Document Type : Original articles

Authors

1 Orthodontic department, faculty of dentistry, Ain Shams university, Cairo, Egypt.

2 Orthodontic department, Ain Shams University, Cairo, Egypt.

3 Professor of Fixed Prosthodontics, Ain Shams Univ, Egypt

4 Orthodontic Department, Faculty of Dentistry, Ain Shams University

Abstract

Aim: To measure and compare the SBS of metallic orthodontic brackets bonded to lithium disilicate (LDC) specimens following etching with hydrofluoric acid (HF) compared to erbium lasers: Er:YAG laser and Er:Cr:YSGG laser.
Materials and methods: 45 Lithium Disilicate (LDC) discs were prepared. Parallel group study design. A total of three groups of samples were created based on the type of ceramic surface etching technique. 15 specimens per group. Gp 1: etched with 9.6% HF acid. Gp 2: etched with Er:YAG laser. Gp 3: etched with Er:Cr:YSGG laser. All specimens were coated with two coats of silane coupling agent. The metallic brackets were bonded following all etching techniques on LDC. For shear bond strength (SBS) measurements, specimens were positioned in universal testing machine. The Adhesive Remnant Index (ARI) used to evaluate the bond failure of brackets using stereomicroscopic images. (ANOVA) was utilized to evaluate and compare the means and standard deviations (SD) among experimental groups.
Results: SBS measurements for Group 1 HF acid exhibited the greatest bond durability (10.01 ±1.34 MPa). Specimens in Group 2, treated with Er:YAG exhibited (6.15 ± 1.55 MPa) SBS values and Group 3, subjected to surface treatment with the Er:Cr:YSGG laser, exhibited the lowest SBS scores. (5.99 ± 01.37 MPa). No major difference exists between the laser groups.
Conclusion: LDC subjected to HFA demonstrated the highest SBS levels. The Er:YAG and Er:Cr:YSGG lasers are suitable for bonding brackets to porcelain surfaces, offering sufficient bond strength and minimized damage to the surface relative to HFA etching.

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