Related Experiment Video
Updated: May 29, 2026
Development of a Direct Pulp-capping Model for the Evaluation of Pulpal Wound Healing and Reparative Dentin Formation in Mice
Published on: January 12, 2017
[An experimental study of expression changes of inducible nitric oxide synthase in rat dental pulp during direct pulp
Xiaofang Zhang1, Yanju Lin, Ya Zhao
1Dept. of Cadres, School of Stomatology, China Medical University, Shenyang 110002, China.
Objective:
To observe the expression of inducible nitric oxide synthase (iNOS) in rat dental pulp after direct pulp capping with calcium hydroxide (CH) and mineral trioxide aggregate (MTA).
Methods:
Samples from 42 Wistar rats were immediately collected at 1, 3, 7, 14, 21 and 28 days after direct pulp capping with CH and MTA. Pulp tissues were studided with immunohistochemical stain. Software for image analysis was used to test the optical density of each specimen. The data were analyzed by paired t-test and Dunnett-t test with SPSS 11.5.
Results:
In normal pulp, the stain of iNOS was negative. After direct pulp capping with CH or MTA, iNOS expression demonstrated weakly positive, positive, weakly positive, negative at different time, the expression was low immediately after capping but became strong after 3 days. Until 7 days the stain became less positive gradually and at 21 days the stain approached normal. The expression was mainly at the fibroblasts, odontoblasts, vascular endothelial cells, neutrophils, etc near the bottom of the pulp capping agent. The diffence of iNOS expression was significant 3 days after direct pulp capping with this two capping agents.
Conclusion:
After direct pulp capping, iNOS expression increasd at first and then decreased, the diffence of capping agents will have an impact on the expression of iNOS 3 days after direct pulp capping.
