In Vitro Evaluation of Antibacterial Properties and Smear Layer Removal/Sealer Penetration of a Novel Silver-Citrate Root Canal Irrigant

Abstract

This study aimed at evaluating the efficacy of a novel silver-citrate root canal irrigation solution (BioAKT) on smear layer removal, sealer penetration after root canal instrumentation and antibacterial activity. Single-root teeth were endodontically treated, sealed with an epoxi-amine resin sealer and irrigated using: Group I: 5.25% sodium hypochlorite (NaOCl); Group II: silver-citrate solution (BioAKT); Group III: phosphate buffer solution (PBS); Group IV: 17% ethylenediaminetetraacetic acid (EDTA). Smear layer removal and silver deposition at the coronal, middle and apical portion of each canal were analyzed using scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS). Sealer penetration into dentinal tubules at coronal, middle and apical portion was assessed through dye-assisted confocal microscopy (CSM). Both SEM and CSM micrographs were evaluated by two examiners (κ = 0.86), who were blind to the irrigation regimens; scores were given according to the degree of penetration of the sealer. Data analysis included Pearson’s x2 and Sidak’s multiple comparisons. Dentin discs were polished and sterilized. Enterococcus faecalis biofilms were grown using a continuous-flow bioreactor under anaerobic conditions for 72 h. Specimens were irrigated with the tested solutions, and bacterial viability was assessed using a tetrazolium salt assay (MTT). Statistical analysis included one-way ANOVA and Student’s post-hoc t-test (p < 0.05). BioAKT and EDTA were the most efficient solutions both in removing the smear layer and allowing sealer penetration. However, at the apical portion BioAKT performed significantly better compared to EDTA both in smear layer removal and sealer penetration (p < 0.05). BioAKT and NaOCl showed comparable antibacterial effect (p = 0.53). In conclusion, BioAKT represents a suitable smear layer removal agent, which allows for reliable sealer penetration at the apical portion of the root canal system and offers significant antibacterial properties.

Physicochemical and Antibacterial Properties of Novel, Premixed Calcium Silicate-Based Sealer Compared to Powder–Liquid Bioceramic Sealer

“…They reported that the tags of tricalcium silicate at 5 mm from the apex using single-cone technique have a depth of 2 mm into the dentinal tubules. The penetration depth of sealer materials into the dentinal tubules depends on the flowability and working time of the sealer [ 36 ], as well as on dentin treatment/irrigation and patency of the entire root canal system [ 44 , 45 ].…”

In Vitro Evaluation of Different Irrigation Protocols on Intracanal Smear Layer Removal in Teeth with or without Pre-Endodontic Proximal Wall Restoration

“…In the present study, a scoring system based on the criteria proposed by Gutmann et al [ 22 ] was applied to all SEM micrographs to evaluate the amount of smear layer at the coronal, middle, and apical thirds. However, to minimize the limitations of the SEM analysis, which allows us to evaluate small areas of the canal walls, each third of the root canal was fully scanned under SEM, and the area with the greatest amount of smear layer was photographed and further analyzed, as recommended in a previous study [ 7 , 24 ].…”

“…In particular, the organic smear layer is constituted by mineralized dentin collagen mixed with residual predentin, pulp tissue, and microorganisms, along with their byproducts. This layer covering the dentin walls prevents sodium hypochlorite (NaOCl) penetration into dentinal tubules [ 7 ], where the presence of bacteria has been also demonstrated [ 8 ]. Thus, the cleaning and disinfection of the untreated root canal walls and the smear layer removal rely on specific irrigation protocol based on the use of a chelating agent, such as ethylenediaminetetraaceticacid (EDTA), and a proteolytic, antibacterial irrigant, such as NaOCl [ 9 , 10 ].…”

Apical Pressure Generated Using Conventional Syringe Irrigation in Immature Teeth—An In Vitro Study

“…Other irrigants, such as ethylenediaminetetraacetic acid, can remove the smear layer, which results from the mechanical preparation of root canal walls [ 1 ]. Today various techniques like ultrasonic irrigant activation are available to enhance irrigation [ 2 ]. However, to deliver irrigants during root canal treatment, syringe irrigation is the most commonly used method [ 3 , 4 ].…”