Smear Layer Removing Ability of Root Canal Irrigation Solutions: A Review

Abstract

Aim:The purpose of this review is to address the smear layer removing the ability of root different canal irrigants including ethylenediaminetetraacetic acid (EDTA), a mixture of tetracycline, acid and detergent (MTAD), tetraclean, citric acid, Q-Mix, maleic acid, and smear clear.Background: Smear layer is a layer which is produced during instrumentation. It contains both organic and inorganic materials. It may also contain bacteria and their byproduct considering the root canal situation. This layer may prevent the penetration of the healing material introduced to the canal to the interior of the dentinal tubules. In addition, it can affect the adaptation of sealing materials to the root canal walls. Review results:The smear layer removal ability of MTAD is superior and faster than EDTA. Tetraclean is similarly composed of an acid, an antibiotic, and a detergent. The presence of doxycycline is believed to help the smear layer removal ability of these irrigants. Antibiotics such as tetracycline had similar smear layer removal ability as even citric acid. EDTA is an amino acid with a chelating ability that sequestrates metal ions. Some believed EDTA smear layer removing ability is better than MTAD, tetraclean, SmearClear, and 20% citric acid which is controversial in case of comparison between MTAD and EDTA. Phosphoric acid is efficient enough to be comparable to EDTA in removing the smear layer. Maleic acid is an organic compound with acid etching smear layer removal. Its ability seems to be similar or even better than EDTA. Citric acid as another organic acid is believed to be used as smear removing agent. HEBP is another chelating agent that can be used in combination with NaOCl; however, HEBP is a weak decalcifying agent compared to EDTA and hence cannot be applied as a mere final rinse. QMiX is a combination of CHX, EDTA, and detergent and should be used at final rinse. It is believed that QMiX is as efficient as EDTA. Smear clear is a 17% EDTA solution including an anionic and cationic (cetrimide) surfactant. The ability of QMiX is similar to EDTA. Conclusion:There are different canal irrigation solutions with various smear layer removal ability that some should be used as a mere final rinse and some should not. Clinical significance:The usage of canal irrigation solutions depends on the clinical situation and preference of the dentists. This study provides a good guide for clinician of the field.

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

“…Citric acid is a weak organic acid with strong chelating properties, which is commonly used in periodontal therapy as dentin conditioner after scaling and root planning, or in restorative dentistry as etchant agent in some protocols before adhesive application. Indeed, the ability of citric acid to decalcify dental hard tissues is due to the chelation of Ca 2+ ions at a slightly acidic pH environment [32]. Citric acid solutions have been also employed as endodontic irrigants with a concentration between 25% and 50%.…”

Influence of the Chelating Solutions in the Resistance of Glass Fiber Posts to the Root Dentin

“…The evaluation of the influence of the EDTA solution for the intracanal dentin in this study was based on studies that affirmed that after its use, interference may occur in the microhardness of the dentin by a reaction with the calcium ions in the hydroxyapatite crystals. 20 Citric acid solutions and Tetraclean were also inserted in the same time interval of EDTA, avoiding methodological biases.…”

“…Erosion, caused by irrigating solutions, has been widely evaluated in the literature with the use of SEM that allows a morphologic detailed evaluation of the prepared surface. 21 According to the literature, [20][21][22] depending on the depth, this erosion can be a contributing factor to the vertical root fracture but may contribute to the increasing rates of wallcleaning of the canal, removing debris and bacteria from the root canal. 22,23 This study used a mechanical agitation by ultrasound due to its acoustic transmission and formation of bubbles due to the phenomenon of cavitation, which explodes and increases the temperature and pressure, resulting in waves of impact against the wall of the canal by removing debris.…”

Efficacy of New Root Canal Irrigant Activation Systems on Removal of Smear Layer

“…The only material which can reach these areas is the irrigating solution, so irrigating solutions have a great role in chemical cleaning and disinfection of these inaccessible areas, and help dissolving the pulp tissue remnants and microorganisms hidden there, improving the prognosis of root canal treatment. (16) Syringe irrigation is used to deliver the irrigating solution to the root canal, but this doesn't insure reaching of the irrigating solution to all parts of the canal, specially the apical third, where apical vapour lock is formed. The apical vapour lock is an air bubble entrapped at the end of micro channels (root canals) at the distal end of irrigant delivery, preventing direct contact between this irrigant and walls of the apical part of the root canal, preventing the irrigating solution from performing its action at this part of the canal.…”