Investigation of Cellular and Tissue Cytotoxicity of Modified Chlorehexidine as an Intracanal Irrigant; An In-Vitro and Ex-Vivo Study

Abstract

Background & Objectives: Sodium hypochlorite is the first choice among the cleaners given its antibacterial properties and tissue solubility. On the other hand, chlorhexidine competes with it in all aspects except for tissue solubility. Surface-active agents or surfactants are compounds used as emulsifiers, irrigants, and accelerators of tissue solubility. Sodium lauryl ether sulfate was the surfactant used in the study and the purpose of the study was to examine the cellular and tissue cytotoxicity of modified chlorhexidine as an intracanal irrigant in vitro and ex-vivo.
Materials and methods: For evaluating the tissue cytotoxicity in this study, 16 male rats were selected, divided into four groups of four, and each day, one of them was implanted under the skin. After anesthesia and shaving the back hair, three separate incisions were made at two cm distance. Then the tested materials (modified chlorhexidine, chlorhexidine, and sodium hypochlorite) were placed inside poly ethylene tubes with an inner diameter of 1.1 mm and a length of one centimeter and a separate polyethylene tube containing the material was inserted in each cut. The animals were then slowly killed by thiopental injection of 0.5% (0.05%) and sampling was carried out to prepare a histological slide. The samples were placed in 10% formalin for two weeks and then the slides were prepared. After slide preparation, only the number of inflammatory cells was counted and scored according to Robbins classification. One must note that, the type of inflammatory cells was not considered in this study and only their accumulation values, 25%, 50%, 75% and more than 75%, were examined. The slide was examined in a Hi Power field. The results were analyzed by non-parametric Kruskal Wallis and Mann Whitney tests.
Results: The toxicity of the solutions tested on fibroblast cells for groups one to four is, respectively, 27.5, 56, 69, 25, 41.75 and from right to left. The results of comparing the means in four groups at level 4 of Landaindicated that the groups do not differ significantly in terms of toxicity. Considering the obtained statistical results, there was a significant difference in terms of histological reaction between the materials used and the histotoxicity of the modified chlorhexidine and chlorhexidine was significantly less than sodium hypochlorite. In terms of time, there was a significant difference between the time periods of 7 and 30 days, 7 and 60 days, 15 and 60 days, and 30 and 60 days.
Conclusion: The results indicated that the resulting compound could be used as a suitable candidate to replace sodium hypochlorite given its disadvantages, which calls for more studies.