Ceramic Bracket Surface Treated with Hydrofluoric Acid, Er, Cr: YSGG Laser, and Phthalocyanine Activated via Low-Level Laser Therapy on Surface Roughness and Shear Bond Strength Bonded to Enamel via Unmodified and Sepiolite-Modified Orthodontic Adhes

Influence of surface pretreatment Hydrofluoric acid (HFA), Erbium yttrium scandium gallium garnet (Er, Cr: YSGG) laser (ECL), and Phthalocyanine (Pc) photosensitizer (Ps) activated by Low-level laser therapy (LLLT) via a light-emitting diode (LED) device on surface roughness (Ra) and shear bond strength (SBS) of ceramic bracket bonded to enamel via unmodified and Sepiolite-modified adhesive. Sixty non-cavitated human maxillary premolars were obtained. Ninety ceramic brackets were classified into three groups based on different pretreatment methods: Group 1: HFA; Group 2: ECL; and Group 3: Pc-LLLT. Twenty samples from each cohort were allocated into two subgroups by adhesive type: unmodified Transbond XT(A) and adhesive-modified Sep-NPs(B) (n = 10). Ra was measured using profilometry followed by surface topography via SEM, SBS via universal testing machine, and degree of conversion (DC) through FTIR spectroscopy. ANOVA and Tukey’s post hoc tests compared Ra, SBS, and DC across groups (p ˂ 0.05). Maximum Ra was observed in the ECL group (1087.43 ± 0.043 µm), while Group 3 (Pc-LLLT) showed the lowest Ra (706.53 ± 0.054 µm). Maximum SBS was recorded in Group 2B (ECL + SepNPs modified adhesive) (8.79 ± 0.48 MPa), while Group 3A (Pc-LLLT + unmodified adhesive) (5.23 ± 0.32 MPa) showed minimum bond integrity. ECL serves as an appropriate substitute for HFA in improving Ra and SBS of ceramic brackets to enamel. SepNPs improved the SBS of orthodontic adhesive to enamel with no significant difference in DC.