An obstructive tooth is a tooth that grows out of position and does not fully erupt into its normal biting position and loses its function. The most common obstructive teeth are the third molars of the upper and lower jaws, which are often referred to as wisdom teeth. Wisdom teeth usually erupt at the age of 18-25. Due to their late eruption, the amount of bone in the jaw is insufficient relative to the amount of teeth, and the wisdom teeth lack clearance for eruption, resulting in their obstruction in the jaw bone. Because the obstruction of wisdom teeth not only makes them lose their function of chewing food, but also brings a series of problems, wisdom teeth should be extracted when the following conditions occur: 1. Repeated inflammation, resulting in local gum redness, swelling, heat, pain, and even serious symptoms such as restricted mouth opening, running pus, and bad breath, clinically diagnosed as wisdom tooth pericoronitis, must be detected early and treated as soon as possible, otherwise it will progress to septic interstitial Infection. The effective treatment is systemic anti-inflammatory therapy and local flushing with medication, which usually heals within a week. Wisdom teeth with one inflammatory symptom and cannot establish normal occlusal relationship with the opposite teeth should be extracted as soon as possible to prevent unnecessary pain caused by re-inflammation. 2.The wisdom tooth has been decayed, and even the nerve is exposed and serious pain occurs. Due to the malposition of the tooth, it is difficult to treat it thoroughly, and because it has no function, it is usually extracted directly without treatment. 3.The anteriorly inclined and obstructed wisdom tooth presses the second molar in front of it, which is easy to cause food embedment and will lead to local periodontitis and caries of the distal and middle adjacent surface of the second molar for a long time. This condition usually appears later, often because of the second molar pain before coming to the clinic. In order to avoid the occurrence of caries on the distal adjacent surface of the second molar, the wisdom tooth should be removed prophylactically. 4.Wisdom teeth that have caused odontogenic cysts or tumors. Wisdom teeth that are completely buried in the jawbone with low growth may form tooth-containing cysts for a long time, leading to destruction and resorption of surrounding bone and pathological fracture, and the cysts may become malignant and have serious consequences. Therefore, wisdom teeth that are completely buried and cannot erupt normally should also be removed as soon as possible. 5, orthodontics need to remove wisdom teeth. Wisdom teeth erupt late, usually only after the end of orthodontic treatment, because the amount of teeth is greater than the amount of bone, their eruption will lead to crowding of the teeth, which will lead to misalignment of the orthodontic teeth, affecting the beauty and function. Wisdom teeth are usually extracted according to the orthodontist’s medical advice. 6. Wisdom teeth that lead to temporomandibular joint disorder. After eruption, the wisdom teeth cannot form a normal occlusal relationship due to their malposition, resulting in jaw trauma and changes in the closed jaw curve, thus inducing temporomandibular joint disorders, pain and popping in the joint area, and generally the discomfort and pain symptoms of the joint will be significantly improved after the wisdom teeth are removed.