Reconditioning of ceramic orthodontic brackets with an Er,Cr:YSGG laser

Abstract

It is now known that erbium lasers are effective in composite removal, but there is minimal information about their efficacy on recycling of ceramic brackets. This study, therefore, aimed to determine the percentage of remaining adhesive on the base and the shear bond strength of debonded ceramic brackets after being reconditioned by an Er,Cr:YSGG (erbium, chromium: yttrium-scandium-gallium-garnet) laser. Thirty premolars were divided into three groups, then bonded with mechanical retention ceramic brackets according to the bracket base conditions: (1) new brackets; (2) debonded brackets cleaned of adhesive with the Er,Cr:YSGG laser at 3.5 W; and (3) debonded brackets cleaned of adhesive with the Er,Cr:YSGG laser at 4 W. Before bonding, the percentage of remaining adhesive on the bases of reconditioned brackets was calculated by using stereomicroscopic images through an image processing software. The brackets were then tested in shear mode in a universal testing machine and the adhesive remnant index scores were determined. The percentage of remaining adhesive on the bases of brackets that were cleaned by the Er,Cr:YSGG laser at 4 W (3.1 %) was significantly lower than that of the 3.5-W laser group (5.9 %) (p = 0.03). No significant difference was found in bond strengths between the new and the reconditioned brackets (p = 0.19). The frequency of bond failure at the enamel-adhesive interface was lower in the laser-reconditioned brackets when compared to the new brackets. The application of Er,Cr:YSGG laser was efficient in removing adhesive from bases of debonded ceramic brackets because it produced comparable bond strengths to new brackets while reducing the risk of enamel damage during debonding.

The effects of three remineralizing agents on regression of white spot lesions in children: A two-week, single-blind, randomized clinical trial

“…In order to minimize measurement errors, the intraoral photographs were taken in similar lighting conditions and the camera was positioned at the same angular and linear position to the tooth surface. The use of MIP4 Student software provided precise measurement for area of WSLs in photographs (28,29). …”

Surface treatment with a fractional CO2 laser enhances shear bond strength of resin cement to zirconia

“…Furthermore, the use of resin cements or primers containing 10-methacryloxydecyl dihydrogen phosphate (MDP) has been shown to enhance the strength of the adhesion by providing chemical retention to zirconia, although the durability of the chemical bond may be compromised in the clinical conditions [1][2][3] . Lasers have been used for different purposes in dentistry among which is conditioning tooth structure or restorative surfaces [4][5][6][7][8][9] . Previous studies employed different lasers such as neodymium-doped yttrium aluminum garnet (Nd:YAG) 10, 11) , neodymium-doped yttrium aluminum perovskite (Nd:YAP) 12) , erbium-doped yttrium aluminum garnet (Er:YAG) 13) , and carbon dioxide (CO2) 14,15) for surface modification of zirconia ceramic, and reported varying degrees of success.…”

Structural and Morphological Changes in Human Dentin after Ablative and Subablative Er:YAG Laser Irradiation

“…[3][4][5][6] Although various lasers have been employed for the purpose of caries prevention, erbium family lasers including Erbium-Doped Yttrium Aluminum Garnet, (Er:YAG) and Erbium, Chromium-Doped Yttrium Scandium Gallium Garnet (Er,Cr:YSGG) are the only ones that can be employed for removing dentin and enamel structures. [7][8][9] Cavity preparation by the Er:YAG laser provides advantages such as low noise and vibration, and less pain and stress for the patients, but it is more expensive and time-consuming than the conventional technique with rotary instruments. The wavelength of the Er:YAG laser (2.94 µm) is greatly absorbed by water and then by hydroxyl groups in hydroxyapatite, making this laser suitable for thermomechanical ablation.…”