RESUMO
Background and Aim: Intracanal medicaments can affect the bond strength of composite to dentine. The aim of this study was to evaluate the effect of 2o/o chlorhexidine [CHX] gel as an intracanal medicament on shear bond strength of three different composite resins to dentin.
Materials and Methods: In this in-vitro study, 60 intact extracted human premolars were utilized. Each tooth was sectioned vertically and dentin of the buccal surface was exposed. Then, specimens were divided into six groups of l0 teeth. In groups l-3, dentin was exposed to CIIX and in groups 4-6, dentin was exposed to saline. All prepared surfaces were rinsed with distilled water and dentin bonding agent specific for each composite was applied on the dentin surfaces.2100, 2350 and P90 composites were applied to the treated swfaces and cured. The shear bond strength was recorded in Newtons and converted to MPa. Data were analyzed using the Kruskal-Wallis and Mann- Whitney U tests.
Results: The lowest mean shear bond strength was reported for normal saline and 2100 composite group [18.47 MPa] and the highest for CHX and 2350 grotry [42.26 MPa]. No statistically significant difference in bond strength values was found between normal saline and CHX groups [p>0.05]. There was a significant difference in bond strength values of different composite resins in normal saline [p<0.05] and also in CIIX groups b<0.05].
Conclusion: chlorhexidine gel 2o/o slightly but not significantly increases the mean shear bond strength of composite to dentin. The type of composite influences the shear bond strength to dentin
RESUMO
The use of calcium hydroxide powder in saline as an intracanal drug is common. Recently, the use of chlorhexidine solution for irrigation due to its antibacterial property has increased significantly. The Purpose of this study was to compare the antimicrobial activity of calcium hydroxide combined with chlorhexidine gluconate against E-Feacalis and to compare the results with the calcium hydroxide mixed with saline and by chlorhexidine alone. In this study, 40 teeth with single canal were used. After removing the crown and preparation of the canal with step-back technique, the root canal was irrigated with EDTA solution to remove smear layer. Then, all the samples were sterilized in autoclave and the roots were infected with E faecalis and incubated. Subsequently, the roots were divided into 3 treatment groups. Group 1 was treated with calcium powder hydroxide in salin, group 2 with calcium hydroxide powder in chlorhexidine, and group 3 with chlorhexidine. All the samples were incubated for a period of one week at 37°C. Sampling was done by paper point. The microbiological samples were plated to count the colony-forming units and the level of CFU was assessed at the wavelength of 540 nm by photometer. The mean number of colonies in all the three groups was assessed by variance analysis, and turbidity and transparency of the samples were assessed via chi-squares [x[2]] test. The results showed that chlorhexidine gel was significantly more effective than calcium hydroxide with chlorhexidine, calcium hydroxide, and control saline solution [p = 0.06]. The results revealed that chlorhexidine gel has antibacterial effects against E-Feacalis. In fact, the study in the field showed that adding chlorhexidine to calcium hydroxide results in an increase in antibacterial effect of calcium hydroxide and reduces the antimicrobial effect of chlorhexidine