Knocking on the teeth three times means tapping on the teeth three times.
Tapping means clenching your teeth empty-mouthed. It is a common dental health care method. Modern medicine believes that this can increase the self-cleaning effect of teeth, exert the stimulation caused by chewing movements, and enhance the resistance of the teeth themselves. . There are differences in previous health care discussions. In short, tapping is done once a day in the morning and evening. The number of tapping each time is arbitrary and can vary from person to person. The force of tapping the teeth does not need to be uniform. It can be done according to the health of the teeth. But you must persevere and never stop to see results.