The slow and progressive loss of hard tissues on the occlusal or adjacent surfaces of teeth due to mechanical friction between teeth is called attrition or wear. The slow loss of hard tissues on the occlusal surface of teeth with age is generally called dental physiological wear. Excessive loss of hard tissues on the occlusal surfaces of teeth due to night grinding, clenching, lateral chewing, etc. is considered pathological wear. Abnormal occlusion or disorder of tooth alignment, such as heavy deep overlap, individual teeth retrusion, etc., will aggravate the wear of teeth due to the restriction of jaw movement. Some people think that teeth are hard and not afraid of grinding, and the more they are worn, the stronger they become, which is actually a misconception. Some people like to use the incisive end of a fixed position to eat melon seeds and other hard-shelled food, and over time, as a result, the enamel in the incisive edge of that fixed position on the excessive wear, forming a groove. Improper brushing can also cause damage to the hard tissue of the neck of the tooth. The manifestations of tooth wear are closely related to the areas where regular friction occurs. Wear that occurs on the occlusal surface of the posterior teeth initially appears as a small, smooth plane at the cusp of the tooth, and then gradually expands and deepens to expose the dentin. As the wear increases, the lingual cusps of the maxillary posterior teeth and the buccal cusps of the mandibular posterior teeth gradually become flat or even depressed, while, on the contrary, the buccal cusps of the maxillary posterior teeth and the lingual cusps of the mandibular posterior teeth appear increasingly long and sharp. Wear of the incisive ends of the incisors caused by biting melons, etc., is usually a curved cut or defect. This characteristic defective tooth is commonly called “melon tooth”. A defect in the cervical part of the labial surface of the anterior teeth or the cervical part of the buccal surface of the posterior teeth is wedge-shaped and is called a wedge-shaped defect. It is generally believed that wedge-shaped defects are caused by a combination of mechanical friction and acid decalcification during tooth brushing. The occurrence and development of wedge-shaped defect may be related to the following factors: the structure of the cervical part of the tooth at the boundary of the glazed tooth bone is weak, easily worn and prone to defects, so the abrasion of brushing this may be the main reason for the occurrence of wedge-shaped defect in the neck of the tooth, and also with the toothbrush, toothpaste, brushing method and the amount of force used when brushing are related. It is based on the fact that people who do not brush their teeth rarely have wedge defects, while people who brush their teeth, especially those who brush crosswise with force, often have typical and severe wedge defects. In addition, acidic foods and acid reflux are also thought to be associated with the occurrence of cervical wedge defects. Hazards of tooth wear Excessive tooth wear has the following hazards: 1. When wear leads to dentin exposure, it can cause tooth sensitivity or pain to cold, hot, sour, sweet and other stimuli. 2, excessive wear leads to tooth pulp exposed, can cause pulpitis, if not timely treatment can even lead to periapical inflammation. 3.When the wear forms too high, too sharp cusps or the neck of the tooth is too thin, it is easy to cause hidden tooth fracture or even tooth fracture, etc. 4.Heavy wear or even flattening of the fossa, groove and tip of the occlusal surface of the teeth leads to a significant reduction in chewing efficiency, forcing the patient to increase the force when chewing food, increasing the burden on periodontal tissues, or chewing out of place, increasing the burden on the stomach. 5.Severe wear of the occlusal surface will cause the teeth to lose the normal contact relationship, which can lead to food embedment and then cause adjacent surface caries and periodontal disease. 6.Severe wear and tear of teeth shorten the height of the lower 1/3 of the face, not only deepen the nasolabial folds, appear pale face, but also appear the symptoms of dysfunction such as pain and soreness in the temporomandibular joint area. Treatment of tooth wear The treatment of tooth wear has the following differences depending on the degree of defect and whether it is secondary lesion. 1.Sensitivity to cold, heat, acid and sweet only, desensitization treatment can be considered. 2.Defects at the incisive end of incisors and cervical wedge-shaped defects can be restored with photosensitive resin filling, and further protection with artificial crowns is appropriate for weak teeth. 3.In case of combined tooth fracture, nuclear crown restoration should be performed on the basis of perfect root canal treatment. 4.For those who have food impaction, it is appropriate to restore the correct adjacent relationship between teeth with artificial crown restoration. 5.For those who have caused misalignment of bite or even temporomandibular joint dysfunction, it is appropriate to take bite reconstruction treatment. How to prevent or reduce tooth wear? According to the specific situation, the following measures can have a positive effect on preventing or reducing tooth wear. 1. Early correction of occlusal abnormalities and tooth alignment disorders so that the jaw can move freely not only in the up and down direction but also in the horizontal direction. 2.Avoid subconscious clenching of teeth. 3.Avoid long-term fixed use of a certain fixed position of a certain tooth to gnaw hard objects. 4.Advocate the use of soft-bristled health care toothbrushes, change toothbrushes and toothpaste regularly, and brush teeth correctly. 5.People who have the habit of grinding their teeth at night should go to the hospital for treatment in time. 6, heavy wear of teeth, the best assembly and bedtime wear with bite pad. 7.For those who have severe tooth hypoplasia, protect the back teeth with artificial crowns as early as possible.