Shear bond strength of rebonded brackets after removal of adhesives with Er,Cr:YSGG laser

Abstract

This study was conducted to examine the bond strength of rebonded orthodontic brackets after adhesive residuals on the surface of the bracket bases were removed by Er,Cr:YSGG lasers. Seventy-six brackets bonded to premolars with a self-etching primer adhesive system were equally divided into four groups after the first debonding with the bracket bases (Group 1) untreated, and treated by (Group 2) Er,Cr:YSGG laser, (Group 3) sandblaster, and (Group 4) Er,Cr:YSGG laser/sandblaster. The treated brackets were rebonded to the new premolars in the same manner as the first-stage experiment. The shear bond strengths were measured, with the bonding/debonding procedures repeated once after the first debonding, and the bracket/adhesive failure modes were evaluated after each debonding. The treated bracket base surfaces were observed under a scanning electron microscopy (SEM). The mean rebond strengths were significantly lower in group 1 than in other groups, and there were no significant differences between the other groups. The mean initial bond strength was significantly higher than the mean rebond strength in group 1 but there was no significant difference between the two in the other three groups. Failures at the bracket-adhesive interface occurred frequently at second debonding in group 1. Under the SEM, residual adhesive was removed from the bracket bases by Er,Cr:YSGG laser, while adhesive remnant was seen underneath the meshwork of the bracket bases and microroughness appeared on the meshwork after sandblasting. Er,Cr:YSGG laser certainly could serve the purpose of promoting the use of recycled orthodontic brackets.

Long-Term Evaluation of Clinical Performance of Directbonded Brackets: An Epidemiologic Survey

“…1 Several methods have been proposed in the literature for reconditioning the bracket bases for rebonding purposes. Sandblasting, 2 laser treatment, 3 microetching 4 and grinding 4 are among the proposed techniques. Precoated brackets have also been proposed to reduce the chair time required for bonding.…”

Shear Bond Strength of Metallic Brackets: An In Vitro Stud

“…Conventional metallic orthodontic brackets were chosen because they are widely used in laboratory tests [3][4][5][6] and therefore widely used in orthodontic practice compared to national self-bonded and conventional imported materials.…”

“…However, it is necessary to assess these products as imported products are thoroughly studied in literature [3][4][5][6], since professionals need to know if these materials exhibit good quality and adequate strength to withstand the stresses imposed by the masticatory system. Shear tests performed in laboratory are one of the most common scientific ways to measure and assess the adhesiveness of restorative materials to dental tissues.…”

“…Undoubtedly, one of the greatest advantages of laboratory tests is the possibility of a strict control of the study phases, since external variables could influence the results. From the classic study that first assessed the adhesive dentistry in 1955 [7], these tests have been used to evaluate the bond strength of dental materials [3][4][5][6][7][8].…”

“…Several studies in literature have analyzed shear tests with metallic and ceramic brackets [9], with recycled brackets [5], with etch self-adhesive systems [10], with metal brackets fixed with composite photo and chemically activated resins [11] and different cleaning methods for orthodontic bracket bases [8]. Based on the above, the aim of this study was to evaluate in vitro the shear strength of metallic brackets.…”