Research and Mechanism Study on Refurbishing Stainless Bracket Using Picosecond Laser Based on Laser Cleaning Technology

Authors:
  • 凌晨凌晨LingChen
    凌晨LingChen
  • 季凌季凌飞JiLingfei
    季凌飞JiLingfei
  • 吴燕吴燕WuYan
    吴燕WuYan
  • 李秋李秋瑞LiQiurui
    李秋瑞LiQiurui
  • 鲍勇鲍勇BaoYong
    鲍勇BaoYong
  • 蒋毅蒋毅坚JiangYijian
    蒋毅坚JiangYijian
  • 杨凯杨凯YangKai
    杨凯YangKai

Abstract
Bracket bonding technology is widely applied in clinical orthodontic practice. However, orthodontic bracket sheds off frequently due to various reasons which results in the advocating of recycling utilization of the brackets by refurbishing. In this study, the refurbishing of Mini Sprint stainless bracket by picosecond laser (wavelengths of 532 nm and 1064 nm, pulse width: <20 ps) is studied. High clean quality without any resin adhesive is achieved which overcome the limitation of edge diffraction effect during conventional laser cleaning technique. There is an evidence that the diffusion of the stress vibration due to the elastic waves generated by ultra-short pulse shots with high frequency is the picosecond laser cleaning mechanism. It is observed that there are differences between the microstructure on the top of columnar bracket base refurbished by picosecond lasers with different wavelengths. It is suggested that localized surface polaritons (LSPs) induced by the original point defects on bracket base surface under the irradiation of 532 nm picosecond laser enhance the energy distribution of laser input, which results in the formation of micro-pit structures on the bracket surface beneficial for the rebonding.