动物造模 z-bo 2022-11-02 502

　　The model of Ⅱ degree root bifurcation defect in mini-pig was established by surgical operation.

　　1. Experimental method 4 Chinese experimental miniature pigs at 13 months old, male, weighing 28.5～31.5k. After conventional anesthesia, the miniature pigs are fixed on the animal operating table, disinfected and draped, centered on the operating tooth, extended 1 tooth position forward and backward, in the middle of the buccal gingival papilla of the second mandibular premolar and the buccal gingiva of the first molar Make a vertical incision in the distal part of the nipple, and use a gum separator to open the gingival flap to fully expose the alveolar bone on the buccal side of the surgical tooth. Use an osteotome to remove the buccal alveolar bone of the experimental tooth to expose the furcation area, and then remove the alveolar 5mm in the furcation area in the occlusal-gingival direction and buccal-lingual direction to prepare the second-degree furcation area alveolar bone Make the defect model, make the root surface level, rinse with 3% hydrogen peroxide and normal saline, and reset the buccal gums. Use a saline cotton ball to gently press on the buccal side to make the mucoperiosteal flap closely fit the bone surface. Use No. 4 suture Suture the gingival flap intermittently. The criterion for successful modeling is that there is a bone defect in the bifurcation zone but not yet connected, and the periodontal probe can enter the bifurcation zone from the horizontal direction at different depths. The stitches were removed 1 week after modeling and kept for 8 weeks. After successful modeling, with the third and fourth premolars on both sides of the upper and lower jaw of each miniature pig as the experimental teeth, a total of 16 experimental teeth from 4 miniature pigs were randomly divided into 2 groups. Model group: only the second degree root score was established Fork defect model, without any intervention; control group: after modeling, 2.2 mg simvastatin gel was injected into the artificial root bifurcation defect, once a week, 50 μl/time, light after injection Press the tissue flap to make it fit closely with the bone surface. Animals in each group were sacrificed after 8 weeks of observation. After the general observation, teeth and periodontal tissue blocks were prepared for the hard tissues with each experimental tooth as the center, and fixed with a volume fraction of 10% formaldehyde solution for histomorphological observation.

　　2. Experimental results Eight weeks after the operation, the animals were in good health. No obvious soft scale was found in the experimental teeth. There was no congestion and swelling of the gums, no bleeding on probing, and no obvious looseness of teeth. In the control group, no obvious soft scale was found in the experimental teeth, some gums were slightly congested and swollen, there was no bleeding during probing, and the teeth were not significantly loosened. Eight weeks after modeling, all the experimental animals’ soft tissues and mucoperiosteal were removed to expose the jaws. It was seen that the root bifurcation area of the model group was empty, and there was basically no new bone tissue growth, a large number of blood vessels and fibrous connective tissue were visible; the control group was almost full of new bone There is no obvious boundary between the defect area and the surrounding bone tissue. There was no significant difference in the height of the defect between the two groups of animals before the experiment. The height of the new alveolar bone in the model group was lower than that in the control group (P<0.05). Pathological examination showed that the new alveolar bone of the experimental teeth in the control group was almost filled with the root bifurcation area, and the trabecular bone mesh structure and mature Haval system were seen, while the model group did not see obvious new bone. The cell count results showed that in the control group, more mature fibrous tissue and hyperplastic blood vessels were seen. The number of osteoblasts was more than that of the model group (P<0.05), and the number of osteocytes was also more than that of the model group (P<0.05).