Periodontal tissues (supporting tissues of the tooth) include: gingiva, alveolar bone, dental bone, and periodontium. Only in the presence of the periodontal membrane can the alveolar bone follow the regeneration. First of all, orthodontics is a prerequisite because of the existence of periodontal membrane. When the periodontium is under pressure, the alveolar bone on one side is resorbed, and when the alveolar bone on the other side is pulled, the teeth can be moved. The periodontium contains various stem cells that differentiate into osteoblasts, osteoclasts, and so on, which is why there is resorption and renewal. A tooth without periodontal membrane is called root and bone cementation, and it cannot move. And then periodontal problems. Because of the resorption of the alveolar bone caused by plaque, calculus, etc., the height of the alveolar bone around the tooth decreases, and at the same time, the height of the periodontal membrane also decreases, forming a periodontal pocket. After periodontal treatment, several types of tissues compete to move up to the teeth, and the growth rate is different: gum > periodontium. So once the alveolar bone recedes, without manual intervention, the gums first hog the place of the periodontium and the periodontium cannot grow, while without the periodontium, the alveolar bone cannot grow. Later on, some people proposed to do periodontal surgery and put a membrane to separate the gum from the periodontium, so as to give the periodontium stem cells enough time to grow up and restore the attachment height of the alveolar bone, called guided tissue regeneration. This is useful but has indications and is more effective for patients with vertical bone resorption. But again, it is very expensive, more than 3,000 for a film. Many people can’t even afford to pay a few hundred dollars for a dental cleaning, let alone buy that very expensive film for an uncertain result. For most people, the goal of periodontal treatment is to maintain the attachment level without further deterioration, and there is not that much manpower to prevent the gums from growing on the teeth before the periodontal membrane. As far as the current state of medicine is concerned, it is not that the alveolar bone cannot regenerate, but rather that it is difficult, if not impossible, to restore the height due to the magic of nature’s design.