动物造模,牙根吸收模型 z-bio 2021-11-09 644

　　In orthodontic treatment, root resorption is a common and difficult complication. There are many related factors that can lead to root resorption, such as age, gender, nutritional status, type of equipment, intensity of orthodontics, treatment methods and treatment process. Due to the irreversibility of root absorption, population clinical studies are mainly retrospective analysis, and animal experiments are an indispensable tool. In previous experimental studies, mice were mainly used animals, and some used rabbits and cats, but these types of animals have obvious disadvantages. For example, the front teeth of mice and rabbits grow once, which is completely different from humans. The disadvantage of cats as a root resorption model is that cats’ teeth are easily traumatized, causing internal resorption of the teeth, and the posterior teeth and mouths of these experimental animals are too small for instrument installation. Therefore, establishing a root resorption model of miniature pigs can provide an important basis for preventing root resorption in clinical orthodontics.

　　Observe the influence of various force values on root absorption. Experimental application There are 7 experimental miniature pigs in China, of which 4 are 6 months old and 3 are 18 months old. Six-month-old pigs choose maxillary lateral incisors, one with experimental teeth and the other with control teeth. For 18-month-old pigs, the mandibular central incisor was selected, one side was the experimental tooth, and the other side was the control group. tooth. Apparatus wearer: Use brass wire or ligature to fix a 0.012 inch nickel-titanium coil spring on the second deciduous tooth (6-month-old pig) or the first permanent molar (18-month-old pig). Apply force every two weeks. The values are 300g and 400g respectively. X-ray: The same technician uses the same X-ray machine to shoot. Each time the film is shot, it will be marked, which is very useful for subsequent measurements and statistics. Before the experiment started, X-ray film was taken of each animal, then the instrument was placed, and the X-ray film was taken again before applying each force. Forty-five days after the force was applied, the animals were sacrificed, the experimental teeth and the control teeth were taken out, and pathological sections and scanning electron lenses were prepared regularly to observe root resorption.

　　Experimental results: (1) According to X-rays, the mandibles of pigs are relatively dense, the roots are very long, and the milk teeth and permanent teeth overlap. Therefore, the apical images of the two are blurred on both sides, and root absorption is difficult, so it is difficult to find out Location and extent. ②Overall observation: The experimental side of the forcing tooth has obvious absorption in the root tip, and the diameter of the apical hole increases, but there is no root resorption on the control side; ③Pathological observation: The top of the forcing tooth is in the resorption of cementum in the apex, Some are absorbed. There is no cement attached. ④ Scanning electron microscope observation: The cement is clearly absorbed and can be removed. Found in the hole of the root tip, the tip is like an insect.