re-contamination.D: Positioning: locator the tooth surface using the ceramic bracket, drawing the positioning reference line of ceramic bracket pasted position.E: the ceramic bracket should be strictly disinfected before using, soaked in 75% alcohol abou 20-30 minutes for disinfection, then rinse the residual disinfectant repeatedly with sterilized water (more than three times, 1 minute each time)F: Paste the ceramic bracket: modulate the bonding material according to requirement, first coated p