Enhanced shear bond strength of ceramic orthodontic brackets with laser surface texturing

The insufficient bond strength between a rigid ceramic bracket and an enamel leads to bracket detachment and orthodontic treatment failure. In this work, a laser-based engineering route with high controllability, high efficiency, and low cost is applied to texture ceramic brackets with surface microstructures to introduce mechanical retention for improved bonding between ceramic brackets and enamels. The influence of the structural features of surface microstructure on the shear bond strength (SBS) of laser-textured ceramic brackets with enamels is systematically studied. The maximum SBS value of 575 +/- 25.16 N is obtained for a ceramic bracket that is textured with a surface grid pattern that has a grid size of 80 mu m and a groove depth of 37 mu m. This SBS value is about four times higher than an untreated bracket. A bracket-resin-enamel model is established to theoretically understand the stress distribution and mechanical behavior of the system under a shear load. The theoretical simulation results evidence concentrated stress at the groove area, suggesting the formation of mechanical retention. The development of a laser surface texturing method to improve the bonding strength of ceramic brackets could promote the bonding reliability of ceramic brackets in orthodontic treatment.