We are taught to use simple horizontal brushing when we are young because the milk teeth are shorter and the gaps are larger, and it is also convenient for young children to learn; as we grow older, our strength increases and our hands become stronger, so if the brushing method remains the same, we often become overly forceful. Each tooth in the human body has a rounded surface, both large and small, and when we brush hard across the teeth, the most force must be on the most prominent arc of the teeth. Although the toothbrush bristles are soft, brushing hard on the hard surface of the teeth can have a negative effect. Think about the truth of drip through stone, the weak but years of force, really can not be ignored. 1, gum recession U weak gums bear the brunt, the thinner the gums recede the higher the chance. Seeing the teeth gradually become longer, and even the roots of the teeth exposed, some people will be very nervous to ask: “Is it periodontal disease?” Although receding gums are a periodontal problem, they are not bacterially caused, unlike what is generally referred to as periodontal disease, and can be restored by minor surgery of gum grafting if necessary. 2, tooth sensitivity U tooth surface enamel is originally a harder structure, and when worn down, it forms polished like a mirror in a particularly shiny area. When the tooth is worn out faster than it can be repaired, the inner layer of dentin will be exposed, and changes in air temperature, acid, sweet, bitter, and spicy in saliva, and toxins released by bacteria lurking in the crevices of the teeth will be transmitted to the inside of the tooth, and a sour and soft uncomfortable feeling will be felt. This sour and slightly painful feeling is often confused with the initial adjacent surface caries, which is somewhat similar. If you have taken X-ray to make sure there is no tooth decay, as long as you improve the brushing method in time, the tooth sensitivity problem will disappear gradually. 3, tooth wear: the habit of brushing hard across the teeth for many years will carve out the traces of age on the teeth and form deep V-shaped grooves in the neck of the teeth near the edge of the gums. In people who habitually brush their teeth with their right hand, it mostly occurs on the left side of the canines and molars. It occurs on both sides in some people, who visit the doctor stating that he brushes his teeth hard even with his backhand! This kind of groove does not need to be treated, if you often feel that there will be food debris filling or tooth sensitivity, it can be filled up like caries. 4. Gum trauma U change the direction of brushing for the first time, or learn to use dental floss or interdental brush, often because of unfamiliar with the direction of operation or too hard, and scrape the gums. If you continue to brush in the wrong way, the more you hurt, the more painful it will be. It is best to ask your dentist to take a look and suspend the cleaning action on the injured area to let the injured gums heal. Tooth cleaning tools are all consumables and should be replaced regularly. If the toothbrush is already deformed after only a few days of opening, or if it has been in use for a month, it will not be able to clean your teeth and will have a lot of problems. Take care of your teeth gently, force is not the same as intention, don’t break your toothbrush!