3个疗程,每个疗程10到15分钟。{"smallUrl":"https:\/\/www.wikihow.com\/images_en\/thumb\/6\/6d\/Avoid-Tooth-Decay-Step-2.jpg\/v4-459px-Avoid-Tooth-Decay-Step-2.jpg","bigUrl":"https:\/\/www.wikihow.com\/images_en\/thumb\/6\/6d\/Avoid-Tooth-Decay-Step-2.jpg\/v4-759px-Avoid-Tooth-Decay-Step-2.jpg","smallWidth":460,"smallHeight":306,"bigWidth":760,"bigHeight":506.31868131868134}2补充维生素C。