[Animal Modeling]-Periodontitis model formed by neck ligation

  (1) Copy method ① Ligated at the level of the gingival margin of the neck of the ferret test tooth with 3.0 silk thread. After 14 days, the animal’s gums became red and swollen and easy to bleed on palpation. After 28 days, their gums were dull red with spontaneous bleeding and obvious periodontitis appeared. ②Ligated the enamel-cementum boundary of the right mandibular molars and premolars of the adult experimental monkeys with 3.0 silk thread. After 2 weeks, the ligated teeth were coated with Porphyria gingivalis obtained from other monkeys, and repeated once after 2 weeks. At 8 weeks, the PD, GI, and PL I of the ligated teeth were significantly increased, and the loss of bone density at 16 weeks was significant, indicating that silk ligation and smearing can effectively induce periodontitis in monkeys. ③Use dental floss to ligate the neck of the experimental teeth (left and right premolars and molars) of adult miniature pigs, and put the ligation thread into the gingival sulcus as much as possible. Then apply cotton fiber-containing mixed bacteria (Porphyromonas gingivalis, Streptococcus mutans, and viscous actinomycetes) in the buccal gingival sulcus and the ligation line; apply the bacteria again in the 4th week after ligation, and then every other week or every other week. Weekly coating bacteria, re-ligate when the ligation thread falls off. At the 11th week after ligation, the ligation thread of the right tooth was removed and the smearing was stopped; the left tooth remained ligated and continued smearing. Model animals were sacrificed at the 20th week after ligation. It was observed that the periodontal pockets of the animals deepened 4-8 weeks after ligation, and the attachment was lost. At 11-20 weeks, the periodontal pockets did not deepen further, and the bleeding index of the gums no longer increased. ④ Two weeks before the start of the experiment, the adult rhesus monkeys were given hygiene measures on their left oral cavity. At the beginning of the experiment, the animals were fed moist fried noodles and soft fruits. The left tooth was not ligated as the spontaneous periodontitis side, and the right tooth Use silk thread to ligate the enamel-cementum boundary as the experimental periodontitis side, check once every two weeks, and re-ligate if the silk thread is missing. The statistics of 1 menstrual examination showed that the average percentiles of redness of the gums on the ligation side and easy bleeding during probing were significantly higher than those of the control side, while the loss of attachment and bone loss were significantly higher than the control side soon after ligation.

  (2) Model characteristics The ligation used in the process of making the model can serve as a plaque fixator. On the one hand, plaque and calculus can be deposited on the ligation line, causing local inflammation and stimulation; on the other hand, the mechanical operation of the ligation can be Periodontal tissues produce irritation and damage, causing nipple erosion, necrosis, ulcer formation between ligated teeth, alveolar crest resorption, periodontal pocket formation and other pathological changes, which induce periodontitis in model animals. Different ligation materials may allow different quality and quantity of bacteria to grow on the surface of the tooth around the ligature, which may affect the course of periodontitis. This model is simple to make, has obvious disease characteristics and is easy to observe.

  (3) The interdental papilla at the ligation site of the comparative medical model animal may appear ulcers, necrosis, periodontal pocket formation, and chronic inflammatory cell infiltration; but compared with clinical human periodontitis, the degree of local inflammatory cell infiltration is lighter. The crest crest also showed only mild absorption (simple ligation group), indicating that in addition to bacterial stimuli, mechanical damage caused by ligation also played an important role in the formation of periodontitis in model animals. Since the damage of periodontal inflammation can progress with time, when establishing periodontitis animal models, the commonly used ligation materials are mainly silk thread, but also cotton thread, elastic rubber bands, and orthopedic steel wires as ligation materials; in order to aggravate animal disease It can be combined with periodontitis diet based on high-sugar soft food while using ligation. Periodontitis formed by two modeling factors of ligation and high-sugar soft food is obviously heavier than periodontitis induced by a single factor. As to whether ligation materials of different thickness and quality can induce periodontitis with the same disease course at the same time during ligation of the same animal, a single ligation, ligation plus smear or ligation plus high-sugar soft food can cause teeth on the same model animal. Whether the course of Zhouyan is the same or not has yet to be determined.