【Animal model】-Rhesus monkey periapical disease model

  (1) Reproduction method Adult male rhesus monkeys are anesthetized with 2.5% thiopental sodium solution by intraperitoneal injection at a dose of 25-50mg/kg body weight. After 0.5h, an additional 25-50mg can be added; the anterior teeth will be removed from the tongue after the animal is anesthetized Face and posterior teeth are opened from the occlusal surface, the pulp is removed, the apical foramen is penetrated, and the reaming drill is used to stimulate the periapical tissue many times, without cotton balls, open in the oral environment, causing periapical lesions. Animals were observed by naked eyes, X-ray film and tissue sections 30, 60, and 90 days after modeling. X-ray evaluation criteria for animal model of apical periodontitis: Grade 0: periapical tissue structure and periodontal space are normal; Grade 1: periapical shadow range<1mm×1mm; Grade 2: periapical shadow range ≥1mm× 1mm.

  (2) Features of the model After the operation, the model animals have loose teeth, swelling of the gums and face with abscess formation, and discharge of pus in the gingival sulcus and sinus. X-ray photographs showed that the periodontal cavity of the animal's apex was widened, the hard plate was damaged or disappeared, and there were areas of sparse bone. Observation under a tissue section microscope showed that a large number of inflammatory cells infiltrated mainly by lymphocytes, macrophages, plasma cells and neutrophils were seen in the periapical tissues of the animals. Granulomas can be seen around the apex of the model animals. The periphery of the granuloma is surrounded by collagen fibers, and the central liquefaction necrosis forms an abscess cavity; the cement absorption of the root tip to 1/3 of the root tip is concave or serrated, and the alveolar bone around the apex Widespread destruction. Different degrees of inflammatory cell infiltration can also be seen in the bone marrow space. While the damage is dominant, a slight tissue repair reaction can be seen.

  (3) Comparative medicine So far, there are two main methods for replicating animal periapical disease. One is to use demyelination and open it in the oral environment to cause infection, and the other is to remove the marrow and open the cavity in the oral environment for 1 week. Filling makes it difficult to drain. This model uses the former method, that is, the monkey teeth are pulped and opened in a 1:3 cavity environment for modeling. 30, 60, and 90 days after modeling, it was found that the monkey periapical lesions were 41%, 58%, and 96, respectively. %. Because monkey teeth and human teeth are similar in anatomy and physiology, the effect is quite satisfactory from the point of view of histopathology of model animals. Therefore, the animal model of periapical periodontitis established by this method can be used for the pathogenesis of human periapical disease and drugs Experimental research on treatment.