الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 145 |  |  |
| | | from | 145 | | |
Abstract
bleaching hypersensitivity.
Material and Methods:
This study was carried to investigate the post bleaching hypersensitivity of the pulp of the continuously growing incisor of Albino rats. Immediately after bleaching and 48 hours after bleaching by:
1- Histological investigation of pulp tissue by haematoxylin &eosin stain.
2- Immunohistochemically measuring of TNFα in pulp sample
3- Measuring substance-P in dental pulp samples by using real-time PCR.
Moreover, the study also investigate either 1% hydrocortisone gel or 5% sodium fluoride gel were better in decreasing the hypersensitivity followed the bleaching procedure.
This study consisted of 56 Albino rat pulp samples of continuously growing incisors. We used the right side of the mandible in histological & immunostaining examination, these specimen were fixed in 10% buffered formaldehyde and decalcified by using solution of 12% EDTA for 3 weeks.
Immunostaining specimen was stained using TNF α antibody. The histological & immunostained samples were examined by light microscopy. The photomicrographs of immunostained slides were analysed using Image Analysis Software. The area percentage for each group was then calculated to be used for statistical analysis. And for the left side of the mandible the pulp tissue was extirpated and added in a specific gel and investigated using real-time PCR. The mean and standard deviation of each group were then calculated to be used for statistical analysis.
Results:
Histological results of the present study showed that the sections obtained after bleaching only immediately showed moderate signs of inflammation which was increased after 48 hours of bleaching and in bleaching and hydrocortisone group. Inflammation signs decreased in the immediate subgroup but, the signs of inflammation increased again in 48 hours subgroup.
Moreover, in bleaching and fluoride group the inflammation signs decreased immediately after bleaching and the effect of the fluoride gel applied in this group sustained for 48 hours.
Immunohistochemically evaluation of the present study showed that the bleaching only group in immediate subgroup show high expression TNFα. Moreover, in the bleaching only group 48 hours subgroup shows that highest expression of TNFα than other groups. In the bleaching and hydrocortisone group the TNFα expression was low in the immediate subgroup but, in the 48 hours subgroup the TNFα expression was higher than immediate subgroup of the same group. In the bleaching and fluoride group, the immediate subgroup showed low expression of TNFα but, the expression of the TNFα in 48 hours subgroup was very low. The TNFα in the control group in both subgroups was nearly not expressed.
The real-time PCR measuring substance P in the same groups and the results was nearly close to the immunohistochemical results.
According to obtained data, it could be concluded that the bleaching material caused inflammation in pulp tissue and this inflammation was sustained for 48 hours. Using 5% sodium fluoride gel is more effective in reducing pulp inflammation compared to using 1% hydrocortisone gel.