Impact of Er,Cr:YSGG laser and bonding protocols on enamel surface integrity and bracket bonding strength: an in vitro study
TL;DR
No significant difference in orthodontic bracket SBS was observed between Er,Cr:YSGG laser conditioning and conventional phosphoric acid etching, and substantial overlap in standard deviation (SD) values was observed among all groups.
Abstract
Adequate enamel conditioning is vital for reliable bracket bonding. Laser-assisted alternatives to conventional acid etching exist, but their impact on shear bond strength (SBS) remains highly controversial. This study aimed to evaluate the effect of Er,Cr:YSGG laser enamel conditioning on the SBS of orthodontic brackets bonded using different composite materials in the presence or absence of a bonding agent. Thirty-six extracted human premolars and molars were randomly allocated into four groups (n=9). Group A received Er,Cr:YSGG laser conditioning followed by bonding with 3M Universal Bonding Agent (3M ESPE, St. Paul, MN, USA) and 3M composite (3M ESPE, St. Paul, MN, USA). Group B (control) received conventional phosphoric acid etching followed by bonding with 3M Universal Bonding Agent and 3M composite. Group C received Er,Cr:YSGG laser conditioning followed by bonding with Nova composite (Imicryl, Konya, Turkey) without a bonding agent, while Group D received conventional phosphoric acid etching followed by bonding with Nova composite without a bonding agent. SBS testing was performed using a universal testing machine, and failure patterns were qualitatively assessed using the Adhesive Remnant Index (ARI). Artificial intelligence technology of IBM SPSS Statistics software (IBM Corp., Armonk, NY, USA) was used for the statistical analysis. The mean SBS values were 13.06±4.20 MPa, 15.29±9.52 MPa, 13.20±8.04 MPa, and 11.41±6.22 MPa for Groups A, B, C, and D, respectively. One-way analysis of variance (ANOVA) revealed no statistically significant difference among the four groups (F(3,32)=0.428, p=0.734). Although Group B demonstrated the highest mean SBS and Group D the lowest, substantial overlap in standard deviation (SD) values was observed among all groups. The qualitative ARI assessment indicated that the predominant failure mode corresponded to score 2. No significant difference in orthodontic bracket SBS was observed between Er,Cr:YSGG laser conditioning and conventional phosphoric acid etching.
