Xiya is to compare the shortcomings of pain, to be more blood, washed relatively rough surface of teeth, dental stains calculus of the re-emergence comes more.

• 洗牙的弊端在于比较痛，会出比较多的血，还有洗后牙齿表面比较粗糙，牙渍牙石的再次出现更加来得快。