Humans have two sets of teeth. The first set of 20, which are informally referred to as ‘milk teeth’, are lost in childhood. The adult set has 32 and consists of four incisors, two canines, four ...

1. Brush for long enough – research indicates that people only brush for 45 seconds 1. 刷牙时间不要太短。研究发现很多人刷牙只刷45秒左右。 2. Rinse the mouth after brushing – fluoride helps to prevent, control and even stop ...