Molars, also known as molars, are the innermost group of teeth, which have the main chewing role in the jaw. Due to their deep location, large shape, many gaps, and difficulty in cleaning teeth, they are most susceptible to cavities. When teeth decay, especially molars, small cavities will spread, causing loss of much tooth tissue, the teeth will gradually become blunt, sometimes only the tooth root remains. At that time, treatment will be much more complicated.