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Disinfectants in Root Canal Treatment

Disinfectants are used in root canal treatment to prevent contamination and eliminate microorganisms in the root canal. Common agents include hydrogen peroxide, iodine tincture, sodium hypochlorite, and chlorhexidine. Mechanical cleaning is crucial for optimal effectiveness.

Author: Gunnar Dahlén • Professor • Department of Oral Microbiology and Immunology • Gothenburg
Reviewed by: Annika Björkner • Dental Specialist • Associate Professor • Public Dental Service Region Kronoberg • Gothenburg University
6 min read
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    This article is based on an original article in Swedish which can be found here

    BACKGROUND

    In root canal treatment, there are two steps that require the use of disinfectants;

    The first is related to accessibility, which requires an antiseptic working method to prevent the root canal from being contaminated with microorganisms. These microorganisms can originate from the tooth, the oral cavity, or the environment.

    The second step is the root canal treatment itself, which is based on a chemo-mechanical disinfection. This means that the disinfectants used during the irrigation of the root canal and as an inter-appointment dressing complement the mechanical cleaning.

    Disinfectants (or antiseptics when used on patients) are, unlike antibiotics, more generally effective. The disinfectant has a microbiocidal (killing of microorganisms) effect by destroying the cell's functions, membranes, and cell walls. This also means that it has a similar effect on the host organism's cells. A balance between the toxic effect on the host's cells and the lethal effect on microorganisms regarding the type of agent, concentration, and exposure time is always necessary.

    Bacteria (especially gram-positive such as streptococci, enterococci, staphylococci, lactobacilli, propionibacteria, and actinomyces rods) are generally less sensitive to the effects of antiseptics than the host's cells and tissues. This means that the use in direct contact with vital tissue should be limited, but it can be beneficially used on tooth surfaces and necrotic root canals during cleaning.
    Another limitation for the effectiveness of disinfectants is their tendency to bind to organic material. This reduces penetration into necrotic and vital tissues as well as the biofilms that form on, for example, the walls of the root canal (the so-called smear layer), which have an inhibiting effect on all disinfectants.

    An effective mechanical removal of necrotic material, biofilms, and microorganisms is a prerequisite for disinfectants to achieve optimal effect.

    The goal of using a disinfectant both for disinfecting the working field and in the root canal is the killing of microorganisms.

    DIFFERENT DISINFECTANTS

    Hydrogen Peroxide 30%

    Peroxides are decomposed by catalase found in tissue cells and blood. This releases oxygen, which is seen through the bubbling effect that occurs when hydrogen peroxide comes into contact with organic material. The antibacterial effect consists of the peroxide simultaneously releasing free oxygen radicals that react with the bacteria's proteins and DNA. The bubbling effect with the release of oxygen also means a loosening of plaque and biofilms, thereby facilitating the penetration of other disinfectants (e.g., sodium hypochlorite and iodine tincture).
    30% hydrogen peroxide thus also has a mechanically cleansing effect. However, the released oxygen can have a negative effect on hypochlorite if these are used simultaneously.

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