Unique endodontic irrigant. Simplified endodontic irrigation protocol, using Endo Rinse (KDent, Quimidrol).
In: La Rosa, G. R. M., Plotino, G., Nagendrababu, V., & Pedullà, E. (2023). Effectiveness of continuous chelation irrigation protocol in endodontics: a scoping review of laboratory studies. Odontology, 1-18. Introduction Endodontic treatment aims to eliminate intracanal infection and prevent reinfection by filling the root canal space. Mechanical preparation is capable of removing microorganisms from an infected root canal. However, after instrumentation, up to 35% of the canal surface area may remain unchanged, which may not guarantee a clean, bacteria-free root canal space. As a result, an active irrigation sequence is usually combined with mechanical treatment. Although irrigants are crucial to the success of root canal treatment, it is important that they do not damage the tissues surrounding the root, are safe for both the patient and the doctor and guarantee the tooth's full functional recovery. Sodium hypochlorite (NaOCl), a non-specific proteolytic agent available in different concentrations (0.5-6%), is used for its remarkable tissue solvent action, antimicrobial and anti-biofilm effects. However, NaOCl is unable to eliminate the smear layer and prevent the accumulation of hard tissue debris. Dentin debris can act as a physical barrier that prevents NaOCl from reaching all anatomical amphractuosities. In addition, the presence of dentin debris reduces the antimicrobial efficacy of NaOCl on the dentin structure. Consequently, considering its inability to remove inorganic tissue remnants, NaOCl is generally followed by a chelating agent such as ethylenediaminetetraacetic acid (EDTA), at a concentration of 15-17% for 1 - 2 min. It is worth noting that chelating agents negatively impact the available free chlorine content of NaOCl and thus reduce its tissue-dissolving capacity, while the antimicrobial action decreases only when the initial NaOCl concentrations are low. To prevent these phenomena, the sequential use of NaOCl/EDTA, known as the "sequential protocol", is routinely used in daily clinical practice. NaOCl is used as an antimicrobial agent during instrumentation and EDTA is applied at the end of instrumentation to promote the removal of the smear layer. A final NaOCl rinse has also been proposed to improve the penetration of NaOCl into the areas that were previously covered with the swab. The sequential protocol results in a wider opening of the dentinal tubules and intertubular tunneling due to dentin erosion. NaOCl/EDTA determines the complete decalcification of the superficial 1 - 5 µm of the intertubular dentin and up to 20 µm of the dentin tubular walls. These structural changes significantly decrease the flexural strength of dentin and can increase the risk of vertical root fractures. To overcome the above problems caused by the sequential use of NaOCl/EDTA, the concept of "continuous chelation" was proposed in 2005. It refers to the combination of a mild chelator with NaOCl for antimicrobial and proteolytic action simultaneous with the removal of the smear layer. According to this protocol, NaOCl is added with the salt of a weak chelator, 1 hydroxyethylidene-1, 1-biphosphonate or etidronate (HEBP or HEDP or etidronate), because the tetra-sodium HEDP salt is extremely compatible with NaOCl. Continuous chelation is an attractive concept due to its multiple benefits: simplification of the clinical procedure, better removal of debris, acceptable tolerability with some dental materials and no reduction in NaOCl's antimicrobial activity and dissolution properties. In addition, chelators promote the detachment of biofilms from root canal walls and eliminate metal ions used by bacteria as nutrients. One of the main concerns associated with their application is the potential chemical reactions between NaOCl and the chelator. In fact, NaOCl is capable of chemically interacting with other irrigants and the resulting mixture of two irrigants (i.e. chelators and antimicrobials) has different effects. It leads to a reduction in the pH of the hypochlorite component and its decomposition into chlorine gas. In addition, the mixture generates intermediate toxic products capable of reducing the clinical performance of NaOCl.
Unique endodontic irrigant
