Clinical Study And Construction Of Animal Model On Phosphorous Osteonecrosis Of The Jaw

Objective: Comparing the differences between chronic phosphorous osteonecrosis of the jaw(PNJ)and Medication-related osteonecrosis of the jaw(MRONJ).Establishing an animal model of osteomyelitis related to the phosphorous osteonecrosis of the jaw,which provided a theoretical basis for further study on the mechanism of PNJ and exploring effective and feasible treatment methods.Methods:1.The clinical data of 69 PNJ patients and MRONJ patients from September2009 to October 2022 were retrospectively analyzed,3 PNJ,3 MRONJ and 3temporomandibular joint ankylosis were token from coracoid process patients as control,and the difference of calcium and phosphorus content in the samples was analyzed by energy spectroscopy,HE,Masson and TRAP staining.2.72 SD rats were selected and divided into experimental group and control group.The control group was exposed to yellow phosphorous vapor,and the control group received air with the same frequency.At 8 weeks after the experiment,all the experimental rats were extracted with the second molar of the right mandible.At the 16 th weekend,the right mandible of rats was photographed by Micro-CT,and the bone injury,bone density and trabecular changes were examined.Paraffin section of HE、Masson and TRAP staining were used to observe the pathological changes in the mandible of SD rats.Results: 1.A total of 69 patients,PNJ patients were all male,mainly with mandible,more women in the MRONJ group,and more cases of the maxillary disease.EDS detection showed that the ratio of calcium to phosphorous in bone tissue of PNJ and MRONJ was lower than that of the control group,and the decrease was the most obvious in MRONJ group(P<0.05).HE staining showed that the trabecular structure of bone in PNJ and MRONJ was disordered,and the number of trabecular bones decreased.TRAP staining showed that the number of osteoblasts in bone tissue of PNJ and MRONJ decreased obviously.2.The weight of SD rats in the experimental group decreased after 4 weeks of exposure,and mandibular sinus appeared in 15 weeks of this experiment.Micro-CT showed that the trabecular density and trabecular width of the experimental group increased(P<0.05).HE and Masson staining showed that the distribution of collagen fibers in the experimental group decreased,and a large number of inflammatory cells were distributed in the extraction fossa without epithelial coverage,while the epithelial coverage of the extraction fossa in the control group was intact.TRAP staining showed that the number of osteoclasts in the experimental group was significantly lower than that in the control group.Conclusions: 1.PNJ are similar to those of MRONJ;2.Yellow phosphorous steam can cause PNJ in SD rats.