Linda has a preference for sweets and has had bad teeth since she was young, including a large tooth in her lower right jaw that has been filled again and again. In recent months, she has been uncomfortable biting into things, and a few days ago the filling material fell out, so she visited a dental clinic near her home. After the examination, the doctor told Linda that the bottom of the pulp chamber of the tooth had been perforated and recommended extraction. However, Linda could not afford to have the tooth extracted, so she came to the dentistry clinic. After detailed examination, the doctor confirmed that the tooth had a perforated pulp base, but the tooth could be preserved through treatment, so the perforation was repaired with MTA (mineral trioxide polymer) and braces were made after root canal treatment, and now Linda’s tooth is back to normal function. The hard tissue of a tooth consists of enamel, bone and dentin, with an internal cavity called the pulp chamber. The so-called pulpal perforation refers to the pathological communication between the pulp cavity and the periodontium due to decay, pathological resorption or pulp treatment errors. Pulpal perforation often causes repeated inflammation of the tissue at the perforated area, alveolar bone resorption, and affects the normal function of the affected tooth, which often leads to the extraction of the affected tooth if not repaired in time, causing undue loss. Therefore, although prevention is important, treatment after the occurrence of pulpal perforation can save the tooth to the maximum extent. Pulpal perforations are difficult to treat and have poor results because of their deep and hidden location, high requirements for perforation repair materials, and limited vision of the doctor during treatment. Therefore, most of the doctors in the clinic choose to give up the treatment in the case of pulpal perforation and suggest the patient to extract the affected tooth or simply fill the tooth directly, but in the end, it is difficult to escape the result of tooth extraction. Extraction is of course a direct solution to the pain, but permanent teeth are not renewable and there is one less tooth to extract. Although extraction can temporarily solve the pain problem, restorative treatment after extraction may be done at the cost of damaging the adjacent teeth. The preservation treatment of pulpal perforation can not only reduce the psychological burden and avoid extraction, but also restore the normal function of teeth and avoid all kinds of discomfort that may be brought by veneers for many patients who are afraid of tooth extraction, especially those who are accompanied by diseases such as blood disorders and hypertension and cannot undergo tooth extraction. In recent years, the emergence of various repair materials with good biocompatibility has significantly improved the restorative treatment of pulpal perforations and also greatly improved the preservation rate of perforated affected teeth. The traditional restorative materials include silver amalgam, composite resin, and glass ionomer, etc., but their restorative results are poor due to various drawbacks. For example, postoperative microleakage of silver amalgam is obvious and irritates the tissue at the perforation; polymerization shrinkage of composite resin during curing tends to lead to poor marginal fit, causing microleakage and inflammation. The new material MTA (mineral trioxide polymer) introduced in recent years has good biocompatibility, good closure, can promote the regeneration of hard tissue, no neurotoxicity, and is a more ideal repair material for medullary perforations. It is worth mentioning that early detection and treatment of pulpal perforation is beneficial to improve the success rate of pulpal perforation preservation treatment and prolong the service life of teeth.