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Title Full Strength 8.25% Sodium Hypochlorite Is More Efficient at Dissolving Organic Tissue than Diluted Sodium Hypochlorite Concentrations During Root Canal Therapy
Clinical Question In regard to dissolving organic tissue during root canal therapy is full strength sodium hypochlorite (8.25%) more efficient than diluted sodium hypochlorite concentrations?
Clinical Bottom Line Full strength 8.25% sodium hypochlorite is more efficient at dissolving organic tissue than 6.0%, 5.0%, 2.5%, and lower concentrations during root canal therapy. Sodium hypochlorite must be constantly refreshed during the root canal procedure to overcome the neutralizing effects of dentin. This is supported by multiple in vitro lab studies all demonstrating the statistical significance of higher concentrations of sodium hypochlorite in acting as a better solvent. The irrigants used in root canal therapy are critically important to the success of the procedure.
Best Evidence (you may view more info by clicking on the PubMed ID link)
PubMed ID Author / Year Patient Group Study type
(level of evidence)
#1) 25791075Cullen/201560 dental pulp samples from extracted human teethLaboratory study
Key resultsDiluted sodium hypochlorite had a diminished capacity to dissolve pulp tissue. Constant refreshing of sodium hypochlorite was required to counteract the negating effects of dentin. 8.25% sodium hypochlorite dissolved the entire pulp sample in 6 minutes while 0.5% sodium hypochlorite dissolved the same pulp sample in 32.5 minutes.
#2) 25506141Taneja/201460 dental pulp samples from extracted human teethLaboratory study
Key resultsThe most concentrated sodium hypochlorite (5.25% in this study) had the strongest capacity for tissue dissolution by weight dissolved over time.
#3) 9477824Turkun/199740 extracted human teethLaboratory study
Key resultsTissue dissolution was significantly greater with the 5% sodium hypochlorite than the 0.5% sodium hypochlorite. The higher concentration of sodium hypochlorite was a significantly greater tissue solvent.
Evidence Search ("sodium hypochlorite"[MeSH Terms] OR ("sodium"[All Fields] AND "hypochlorite"[All Fields]) OR "sodium hypochlorite"[All Fields]) AND ("dental pulp"[MeSH Terms] OR ("dental"[All Fields] AND "pulp"[All Fields]) OR "dental pulp"[All Fields] OR "pulp"[All Fields]) AND dissolution[All Fields]
Comments on
The Evidence
Validity: These studies were conducted with a high degree of integrity. The groups were matched pairs and treated identically. There were valid positive and negative controls and all of the samples were included in the studies. Although in vitro studies are considered a low level of evidence the experiments were conducted well and there was minimal bias. Perspective: The overwhelming evidence suggesting higher concentrations of sodium hypochlorite are more effective for root canal therapy is not surprising. Dentin counteracts the effects of sodium hypochlorite, thus stronger concentrations and constant refreshing of the irrigant is the best way to overcome this problem. Faster dissolution allows for less contact time in the root canal system to achieve the same results.
Applicability This information is relevant to every non-surgical root canal therapy procedure. Sodium hypochlorite is used almost universally across the world, and concentrations tend to vary by region. The argument for diluting sodium hypochlorite is that higher concentrations are more toxic to vital tissues. Although this is true, sodium hypochlorite is not supposed to reach vital tissues; it should remain completely within the tooth. Sodium hypochlorite above 0.5% is required for adequate root canal therapy and concentrations above 0.5% cause rapid tissue necrosis if injected into apical tissues.
Specialty/Discipline (Endodontics) (General Dentistry)
Keywords Endodontics, irrigants, bleach, sodium hypochlorite, disinfection, pulp dissolution
ID# 3117
Date of submission: 11/15/2016spacer
E-mail djweyh5@gmail.com
Author David J. Weyh, DDS
Co-author(s) e-mail
Faculty mentor/Co-author James Wealleans, DDS
Faculty mentor/Co-author e-mail kiwiperu@hotmail.com
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