الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 117 |  |  |
| | | from | 117 | | |
Abstract
Eighty extracted upper central incisors were cleaned and shaped by the stepback technique. The roots were sterilized by Sterrad sterilization and each root was inoculated with 10 of the microbial suspension of S.aureus, E.coli and C.albican and incubated at 37 for 48h in moist chamber. After incubation, the specimens were divided into 3 groups. To determine the cytotoxicity; Trepan blue exclusion technique was used and the number of the viable and dead cells was determined using Haemocytometer slides. The test solutions; 0.5 and 1 % carbopol, 2.5 % NaOCL and 17 % EDTA were added individually to the prepared culture cells and incubated for 24, 48 and 72 hr at 37(R@(BC. Selected specimens were examined by scanning electron microscope (SEM) to evaluate the smear layer. Results of the antimicrobial test showed that NaOCL was the most effective solution and carbopol came next. The alternate use of irrigants was more effective than irrigants used separately, especially when 1% carbopol was used followed by 2.5% NaOCL. C.albican was almost completely eradicated due to the effect of this combination. Results of the cytotoxicity showed that carbopol solution at 1% concentration was more biocompatible than EDTA. There was no significant difference in the biocompatibility of 0.5% and 1% carbopol. Sodium hypochlorite at 2.5% concentration was the most toxic solution at the three time periods. SEM evaluation showed that carbopol at 1% concentration removed the smear layer completely in the coronal and middle thirds of the root with an excessively large number of open dentinal tubules.