Byline: Mohamed. El Sayed
Aim: This study is aimed to evaluate the impact of three irrigating solutions on the apical sealing ability of three endodontic sealers. Materials and Methods: One hundred maxillary central incisors were decoronated, and their roots were assigned into three experimental groups (n = 30 each) according to the nature of the irrigating solution and two control groups (n = 5 each). Each experimental group was divided equally into three subgroups (n = 10 each) according to the type of root canal sealer. All root canals were instrumented using ProTaper Universal rotary system and irrigated with 3% sodium hypochlorite (NaOCl/Group 1), 3% hydrogen peroxide (H[sub]2O[sub]2/Group 2), and 2% chlorhexidine gluconate (CHX/Group 3). The final irrigating solutions for all groups were 17% ethylenediaminetetraacetic acid (EDTA) and distilled water. The continuous-wave technique was used to fill the prepared canals with the following materials: MTA-Fillapex/Gutta-percha (Subgroup A), AH Plus/Gutta-percha (Subgroup B), and Realseal SE/Realseal (Subgroup C). The microleakage was assessed after 72 hours using the linear dye penetration method. The results were statistically analyzed with one-way analysis of variance. Results: Significant differences were found only between the experimental groups (P < 0.05). All root canal sealers after irrigation with 3% H[sub]2O[sub]2 showed the lowest amount of leakage. The highest apical leakage was observed when 3% NaOCl and 2% CHX were used. Conclusions: The type of irrigating solution could affect the apical sealing ability of experimental sealers used with the continuous-wave obturation technique. Root canal irrigation with 3% H[sub]2O[sub]2+17% EDTA increased the apical sealing ability of all root canal sealers. Root canal irrigation with 3% NaOCl or 2% CHX +17% EDTA decreased the apical sealing ability of all root canal sealers.
An effective root canal treatment requires appropriate cleaning, shaping, and obturation of the root canal system. Root canal instrumentation is not adequate to get ride-off all microorganisms from the infected root canal system due to the enormous variations in its anatomical structure. Consequently, different types of chemical irrigants, such as sodium hypochlorite (NaOCl), chlorhexidine gluconate (CHX), and hydrogen peroxide (H[sub]2O[sub]2), have been proposed by different authors to reduce the bacterial load in the infected root canals.,,, However, these irrigating solutions were not able to remove the smear layer that is formed after the root canal instrumentation. Therefore, 17% ethylenediaminetetraacetic acid (EDTA) was recommended to be used as an adjunctive solution to remove this layer and improve the quality of adhesion and sealing capacity of root canal sealers.
The use of irrigating solutions may alter the chemical and physical properties of the radicular dentin, and in turn, they may reduce the adhesion or bonding capability of the obturation materials with adjacent dentin.,, Some irrigating solutions such as NaOCl and H[sub]2O[sub]2 can cause significant changes in the collagen structure by dehydration and removal of fibrils required for the formation of the hybrid layer. Therefore, the monomer penetration into the radicular dentin may be insufficient and consequently, the bond strength of the bondable root canal sealers becomes weak. On the contrary, it...