| Objective The rat model of irreducible pulpitis was established,and 2.5%Na Cl O solution was used as a washing agent before pulp capping in the treatment of rat inflammatory dental pulp,and the effect of sodium hypochlorite on the healing and repair process of dental pulp in rats was evaluated,so as to provide some reference for the clinical treatment of irreducible pulpitis.Methods Bilateral maxillary molars(48 teeth)of 24 8-week-old male SD rats were randomly selected and pulpitis models were established by pulp cavity exposure for 24 hours.Then part of the crown pulp was removed and divided into experimental group(group A)and control group(group B)according to different flushing methods.The experimental group(group A)were washed with 2.5% Na Cl O and the control group(group B)were washed with normal saline.After hemostasis,the pulp was covered with i Root BP Plus and the cavity was sealed with glass ionomer.After 1 day,7 days and 28 days,4 teeth(8 teeth)were randomly selected from each group.The animals were killed and the experimental specimens were prepared.The effects of sodium hypochlorite on dental pulp inflammation and tissue repair were evaluated by HE and Masson’s Thichroe staining and CD68 immunofluorescence staining.Results1.HE and Masson’s Thichroe staining results: there was no significant difference in pulp inflammation,tissue destruction and restorative dentin formation between sodium hypochlorite group and normal saline group on the 1st,7th and 28 th day after operation,respectively.There was no significant difference in the effect of postoperative time on inflammation and tissue changes between the two groups(P > 0.05).For sodium hypochlorite group,the postoperative time had a significant effect on the formation of reparative dentin(P < 0.05): 28 days > 7 days > 1 day.In the control group(saline group),the formation of restorative dentin on the 28 th day after operation was significantly more than that on the 7th day and 1st day(P < 0.05),but there was no significant difference between the 7th day and the 1st day(P > 0.05).2.The results of CD68 immunofluorescence staining: the expression of CD68 in normal dental pulp tissue was very low.There were more CD68-labeled positive cells infiltrating around the pulp hole wound in each experimental group,while a small amount of infiltration was scattered in the root pulp tissue.The results of mean fluorescence intensity measurement showed that the expression intensity of CD68 in the two experimental groups showed a downward trend,but the expression level of CD68 in sodium hypochlorite group and normal saline group was significantly higher than that in normal dental pulp at different time points(P<0.01).On the 1st,7th and28 th day after operation,there was no significant difference in the expression of CD68 between sodium hypochlorite group and normal saline group(P>0.05).Conclusion1.2.5%Na Cl O and normal saline used as i Root BP Plus pre-pulp capping irrigating agent showed similar effects on pulp inflammation,tissue destruction and restorative dentin formation after operation,and did not affect the healing process of inflamed pulp.2.After the vital pulp therapy of irreversible pulpitis,the root pulp still had inflammatory reaction and histological degeneration to a certain extent,and did not return to the normal pulp tissue. |
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