Although brushing can clean your mouth and prevent tooth decay, incorrect brushing habits can damage your teeth and lead to dental disease. The common “wedge-shaped defect” is caused by bad brushing habits. “Wedge defect” (commonly known as “root removal”) is a common disease among middle-aged and elderly people in China. It occurs mostly in the cervical part of the tooth, near the gum. Due to the weak tissue structure of the neck of the tooth and low resistance to wear, mechanical friction over time forms a deep channel, and even causes gum abrasion and atrophy. In addition, the erosion of acidic substances in the oral cavity can easily decalcify the hard tissues of teeth and lead to “wedge-shaped defects”. After middle age, the wear penetrates deep into the dentin and the teeth become easily irritated and painful when exposed to hot, cold, sour or sweet. Further wear can lead to pulp inflammation, root inflammation and even tooth fracture. Once a tooth has a “wedge-shaped defect”, it should be treated promptly by a doctor according to its condition. In general, mild and moderate cases only cause tooth allergy symptoms, and some patients do not have any discomfort. Desensitization or filling methods can be used to solve the problem quickly. Severe defects can expose the interdental space and cause acute pulpitis, periapical infection or even tooth fracture. To prevent tooth damage, care should be taken to avoid some wrong brushing habits. First, do not brush horizontally and do not use too much force when brushing. Secondly, do not use toothbrushes with hard bristles and unrounded tips. Third, avoid using toothpaste that contains rough abrasives. Tooth brushing is recommended to adopt the correct brushing method (vertical brushing method), use soft health care toothbrushes, and use toothpaste containing high quality abrasives.