Abstract:

Objective To investigate the effect of iRoot BP Plus on the repair of dental pulp cavity during pulp injury in rats, and to explore the possible role of iRoot BP Plus in the process of damage repair. Methods Bilateral maxillary first molars of 60 8-week-old SD rats were treated with direct pulp capping after pulp opening. They were divided into iRoot BP Plus group(BP group)and control group. After histological processing, the damage of dental pulp tissue and the calcification of pulp cavities were observed by microCT and HE staining. mRNA was extracted from rat dental pulp tissue, and the expression of inflammation and mineralization genes were detected by real-time quantitatitive PCR. Results The results of this study showed that the dental pulp tissue had different degrees of calcification at 1, 4 and 7 days after direct pulp capping. There was no significant difference between the BP group and the control group on the 1st day after the operation, but on the 4th and 7th day after the operation, a regular calcified bridge was formed at the pulp hole in the BP group, and more pulp tissue was retained in the pulp cavity. In the control group, a large area of irregular calcified tissue was formed below the pulp hole. HE staining results showed that the pulp tissue had a heavy inflammatory response, and a large number of inflammatory cells infiltrated near the pulp orifice on the first day after the operation. On the 4th and 7th days after the operation, mineralized tissue began to form near the pulp orifice in the BP group, and healthier pulp tissue was retained in the pulp cavity. The gene levels of IL-1β and TNF-α in the BP group were lower than those in the control group, and the gene expression levels of mineralization indexes COL1 and DSPP were higher than those in the control group. The difference was statistically significant(P<0.05). Conclusion Dental pulp injury can induce the immune defense response. If the inflammation is not well controlled, it will stimulate the calcification of dental pulp cavities. iRoot BP Plus can better regulate the dental pulp microenvironment, control the development of inflammation, reduce the formation of adverse calcified masses in the pulp cavity after pulp injury, and preserve more pulp tissue.

Key words: pulp inflammation, dental pulp repair, iRoot BP plus, microCT