Title Sodium Hypochlorite Concentration Has No Effect on Postoperative Pain Subsequent to Non-Surgical Root Canal Therapy
Clinical Question For a patient needing non-surgical endodontic therapy, would an irrigant with lower sodium hypochlorite concentration (<3%), as compared to one with a higher concentration (>5%), reduce post operative pain?
Clinical Bottom Line Irrigants with a low sodium hypochlorite concentration (<3%) does not improve post-operative pain outcomes in patients needing non-surgical root canal therapy over one with a high concentration (>5%).
Best Evidence  
PubMed ID Author / Year Patient Group Study type
(level of evidence)
37466716Sabino-Silva 20238 studies/891 teeth treated with NSRCTMeta-Analysis
Key resultsThe overall prevalence of post-operative pain for patients treated with high (>5%) or low (<3%) concentration sodium hypochlorite were 39% (I2=85.15, p<.001 CI [0.27, 0.51]) and 45% (I2=89.85, p<.001, CI [0.31, 0.59]), respectively. These results were not statistically significant and substantial heterogeneity was identified as a problem. “Absent pain” was the most prevalent score, regardless of time and sodium hypochlorite concentrations. The authors stated, “using low concentrations of NaOCl during endodontic treatment will probably not be sufficient to prevent the occurrence of postoperative pain.”
33607121Domenech 2021169 teeth treated with single-visit NSRCTRandomized Controlled Trial
Key resultsThree groups of sodium hypochlorite concentrations (2.5%, 5.25%, and 8.25%) were tested. The authors found that for single-visit non-surgical root canal therapy (NSRCT), there was no significant difference in post-operative pain among the groups. Instead, it was found that increased time of the irrigant in the root canal (>10 min) and overfilling significantly increased post-operative pain.
30827769Verma 2019100 necrotic mandibular molars treated with 2-visit NSRCTRandomized Controlled Trial
Key resultsThere was no difference in clinical post-operative pain outcomes (incidence and scores) when using low concentration (1%) or high concentration (5%) sodium hypochlorite irrigant in patients with necrotic teeth receiving two-visit NSRCT.
37466716Farzaneh 2018110 vital teeth with single-visit NSRCTRandomized Controlled Trial
Key resultsVital mandibular molars treated with a higher concentration (5.25%) of NaOCl had significantly less pain for the first 72 hours after single-visit NSRCT compared to the teeth treated with a lower concentration (2.5%) (P = 0.021). There was no difference in pain between the two groups beyond 72 hours.
Evidence Search Endodontics AND Sodium Hypochlorite AND Pain
Comments on
The Evidence
Sabino-Silva’s meta-analysis illuminates the lack of concrete evidence that correlates the effects of sodium hypochlorite concentration on post-operative pain. Despite the large sample size, the data available exhibited significant heterogeneity (I2=>85%) and no statistically significant difference was found between the groups. Domenech’s randomized controlled trial of 169 teeth was appropriately blinded and found no difference in post-operative values in patients with both vital and necrotic diagnoses treated with single-visit NSRCT. Verma’s randomized controlled trial of 100 necrotic molars that had two-visit NSRCT were appropriately randomized, but not blinded. The study found no statistical difference in post operative pain with either sodium hypochlorite concentrations. Lastly, Farzaneh presented a double-blinded RCT which found that vital teeth treated with a higher concentration of sodium hypochlorite initially had less pain. However, the exclusion of patients with periapical pathosis may account for the statistical difference found at early post-operative timepoints.
Applicability In clinical practice, patients may commonly have significant anxiety about the pain associated with non-surgical root canal therapy (NSRCT). Dental practitioners who believe that sodium hypochlorite contributes to post-operative discomfort may perform NSRCT using irrigants with lower sodium hypochlorite concentration. Based on this literature review, there is no evidence that supports the hypothesis that using a lower strength sodium hypochlorite concentration would reduce post-operative pain compared to a higher concentration. There is no need to dilute the solution for the intention of preventing post-operative pain. Conversely, the use of a more concentrated irrigant may reduce post-operative pain in the first 72 hours and improve patient satisfaction.
Specialty (Endodontics) (General Dentistry)
Keywords Sodium Hypochlorite, Post-Operative Pain, Non-Surgical Root Canal Therapy
ID# 3534
Date of submission 10/16/2023
E-mail kurcz@livemail.uthscsa.edu
Author Rachel Kurcz, DDS
Co-author(s) Janice Mach, DMD
Co-author(s) e-mail machj@livemail.uthscsa.edu
Faculty mentor
Faculty mentor e-mail
Basic Science Rationale
(Mechanisms that may account for and/or explain the clinical question, i.e. is the answer to the clinical question consistent with basic biological, physical and/or behavioral science principles, laws and research?)
None available
Comments and Evidence-Based Updates on the CAT
None available