Wisdom teeth: The four innermost teeth on the alveolar bone are called the third molars (one on each side). Because these four teeth begin to erupt around the age of 20, when the physical and psychological development of people is close to maturity, these teeth and “wisdom to come” almost synchronized, so they are called “wisdom teeth”. In the growth of wisdom teeth, individual differences, some people grow before the age of 20, some people grow at the age of 40, 50, some people do not grow throughout their lives, which is normal. Some people may have only one or two wisdom teeth, and some wisdom teeth may stop growing halfway through their growth – a condition known as “wisdom tooth blockage,” or blocked teeth. When a wisdom tooth grows, only part of the crown may be exposed to the gums, or it may be completely buried in the jawbone. The root of the tooth may be deformed or may grow in the direction of the maxillary sinus or the mandibular nerve. It is a curved body layer film that clearly shows the presence of wisdom teeth obstruction on the left and right side of the jaw, and it is a case of lateral obstruction. The eruption of the third molar (wisdom tooth) has been completely blocked by the second molar. In this case, the third molar should be extracted as soon as possible. Otherwise, the long-term pressure will lead to root resorption of the second molar and affect the chewing function. Which wisdom teeth can be considered for extraction? The following are the most common indications for tooth extraction: 1. Repeated pericoronitis caused by mandibular blocked wisdom teeth (the surrounding gums are red, swollen, painful and cannot be bitten); 2. Decay of the mandibular blocked wisdom teeth themselves or decay of the second molar (the wisdom teeth have been decayed or the adjacent front teeth are decayed because the wisdom teeth are too far back and cannot be cleaned thoroughly by brushing); 3. Lateral food impaction between the wisdom teeth and the adjacent teeth ( Always stuffed between the wisdom tooth and a tooth in front). 4, caused by compression of the second molar root or distal middle bone resorption; of course all problems can not be generalized, so what kind of wisdom teeth are worth preserving? Here are a few common indications for reference only: 1, normal eruption up to the jaw plane of the adjacent teeth, after removal of the distal mid-covered gum, can all expose the crown and establish a good biting relationship with the opposing teeth; 2, when the second molar is missing or can not be retained due to disease damage, if the angle of inclination of the blocked wisdom tooth proximal mid does not exceed 45 degrees, it can be retained as a restoration (veneer) of the abutment to avoid the loss of the free end; 3, the Those who are completely buried in the bone, have no communication with neighboring teeth, and have no symptoms of nerve pain caused by pressure on the nerve, can be temporarily retained.