Clinical Efficacy of a Natural Biopolymer-Based Irrigant

Irrigation is a process performed to make the mechanical preparation easier through lubrication by wetting the root canals with liquids of different types and concentrations, and to ensure the disinfection of the root canals by removing the organic/inorganic debris, infected pulp tissue, microorganisms, soft and hard tissue residues from the root canals both physically and chemically.

For many years, sodium hypochlorite at a concentration of 0.5-5.25 percent has been the gold standard and one of the most regularly used irrigation solutions in endodontics. Sodium hypochlorite has various features, such as antibacterial activity due to its proteolytic potential and tissue dissolving ability.

However, NaOCl may be cytotoxic to the periradicular tissues, particularly at high concentrations. AS such, postoperative pain is a concern when highly concentrated NaOCl solutions are used in single-visit treatment of non-vital teeth because of the risk of extravasation of the irrigant into these tissues.

Recently, herbal products gained research interest worldwide because of their medicinal properties including high biocompatibility, anti-microbial, and anti-inflammatory properties favoring their use as root canal irrigants.

Chitosan is a naturally occurring polysaccharide. It is nontoxic, biocompatible, and biodegradable. Its use in the field of endodontics was based on its broad-spectrum antimicrobial activity and considerable chelating effects.

Nanoparticles possess better antimicrobial activity thanks to their polycationic/polyanionic nature together with their high surface area and charge density, providing more interaction with the bacterial cells . Therefore, chitosan nanoparticles (CNPs) have been employed in different health-care domains including root canal therapy.

Chitosan has antimicrobial effects against a broad of gram-positive and gram-negative bacteria. Previous in-vitro studies have demonstrated the significant antibiofilm efficacy of CNPs. It has the ability to interfere with bacterial adhesion thereby hindering the biofilm formation.

The antibacterial mechanism of chitosan has been attributed to its polycationic nature that interacts with the negatively charged surface of bacteria, altering cell permeability and resulting in the leakage of intracellular components. In addition, CNPs are able to inhibit bacterial enzymatic degradation reducing the possibility of bacterial penetration.

Conventional irrigation with syringes has been advocated as an efficient method of irrigant delivery before the advent of passive ultrasonic activation. This technique is still widely accepted by both general practitioners and endodontists. The technique involves dispensing of an irrigant into a canal through needles of variable gauges, either passively or with agitation. The latter is achieved by moving the needle up and down the canal space. Irrigation tip gauge and tip design can have a significant impact on the irrigation flow pattern, flow velocity, depth of penetration, and pressure on the walls and apex of the canal.

Despite its wide use, it appears unable to clean and disinfect areas beyond the main root canal . In addition, it has been linked to a number of irrigant extrusion.

Negative pressure irrigation is an alternative method for the delivery of irrigants inside the root canal that was proposed in order to minimize the risk of irrigant extrusion through the apical foramen and provide better cleanliness and disinfection. Negative pressure irrigation allows potentially large volumes of irrigant to reach the apical region and better debridement of the apical root canal. Irrigants are delivered by a syringe and needle inside the pulp chamber and a fine suction tip placed near working length creates the necessary negative pressure that drives the irrigant into the canal