Sodium Hypochlorite as a Mouthwash


Certain dentists have advised patients to rinse with sodium hypochlorite as an adjunct to daily toothbrushing. There is not so much about it in respective databases. A quick search using search terms

(“sodium hypochlorite”[MeSH Terms] OR (“sodium”[All Fields] AND “hypochlorite”[All Fields]) OR “sodium hypochlorite”[All Fields]) AND ((“mouthwashes”[Pharmacological Action] OR “mouthwashes”[MeSH Terms] OR “mouthwashes”[All Fields] OR “mouthwash”[All Fields]) OR (“mouthwashes”[Pharmacological Action] OR “mouthwashes”[MeSH Terms] OR “mouthwashes”[All Fields] OR (“oral”[All Fields] AND “rinse”[All Fields]) OR “oral rinse”[All Fields]) OR ((“mouth”[MeSH Terms] OR “mouth”[All Fields] OR “oral”[All Fields]) AND (“therapeutic irrigation”[MeSH Terms] OR (“therapeutic”[All Fields] AND “irrigation”[All Fields]) OR “therapeutic irrigation”[All Fields] OR “irrigation”[All Fields]))) AND ((“gingivitis”[MeSH Terms] OR “gingivitis”[All Fields]) OR (“gingival diseases”[MeSH Terms] OR (“gingival”[All Fields] AND “diseases”[All Fields]) OR “gingival diseases”[All Fields] OR (“gingival”[All Fields] AND “disease”[All Fields]) OR “gingival disease”[All Fields]),

yields only six papers of which four are review articles which were not further considered in the analysis below. One article dealt with the adjunct effects of subgingival irrigation of chlorhexidine and sodium hypochlorite on scaling and root planing and was not considered either. The study by De Nardo et al. (2012) refers to a pilot study by Lobene et al. (1972) in which 3% hydrogen peroxide and 0.5% NaOCl were used as a mouthwash in a pulsating irrigating device which was also considered here.

The study by De Nardo et al. (2012) describes the effects of 0.05% sodium hypochlorite oral rinse on supragingival biofilm and gingival inflammation. The study is a randomized, placebo-controlled, investigator-blind parallel group trial in 40 male subjects with gingival disease or mild periodontitis (not more than 2 mm attachment loss). The experimental gingivitis protocol (Löe et al. 1965) was followed. After a pre-experimental period of 30 days had been completed, when supra-and subgingival scaling, polishing and oral hygiene instructions were done in order to restore gingival health, participants withdrew from any oral hygiene measures for 21 days. Forty-two subjects were randomly assigned to either rinsing twice daily with 15 ml 0.05% sodium hypochlorite for 60 s, or to rinse twice daily for 60 s with 15 ml distilled. Since participants were inmates of a prison, rinsing was supervised by a professional dental practitioner who was not the dental examiner. The Quigley-Hein plaque index as modified by Turesky et al. (1970), a modified Löe and Silness gingival index (1963) with visual assessment of the gingiva, and the % sites bleeding on probing were assessed at baseline and after 21 days. Forty subjects completed the study. Twenty-one days after cessation of oral hygiene measures, plaque index, gingival index and the % sites bleeding on probing had increased in both groups. In the experimental test group rinsing with sodium hypochlorite, increases were significantly lower when compared to the group which rinsed with distilled water.


The differences in the mean Quigley-Hein plaque index (1.98 vs. 3.82), mean Löe & Silness gingival index (1.00 vs. 2.10) and in the % of sites bleeding on probing (56.7 vs. 93.1) were all highly significant (p<0.001) and clinically relevant, see Table. All subjects rinsing with sodium hypochlorite developed extrinsic brown tooth stains while stain was also seen in 35% subjects who rinsed with water. Thirty-five per cent of subjects using sodium hypochlorite but no subject rinsing with water presented with redness of the tongue after 21 days. Subjects rinsing with sodium hypochlorite reported a “bleach taste”, and 85% described this as “tolerable”. Forty-five per cent reported a burning sensation when rinsing with sodium hypochlorite. Subjects who rinsed with sodium hypochlorite reported a cleaner mouth and less bad breath despite not brushing their teeth for 21 days. Authors conclude that “sodium hypochlorite, which is widely available as household bleach, can benefit all periodontal patients, but its low price makes it particularly suitable for individuals with low incomes.”

Lobene et al. (1972) had conducted a pilot study among six college students who suspended all oral hygiene procedures for two days before and during test periods. A complicated protocol was used. Gingival inflammation was assessed visually on a 4-score scale and resting plaque pH was measured at maxillary right and left canines and premolars. On day 5, plaque was harvested and dried at 105 degrees Celsius. The test solutions (32 ml) 1% hydrogen peroxide and 0.5% sodium hypochlorite prepared from a stock solution of 5% NaOCl were applied on days 2-4 for 15 seconds in a pulsating irrigation device on the right side of the maxilla while the left side was irrigated with tap water. Plaque mass harvested from sodium hypochlorite- and hydrogen peroxide-treated teeth weighed 47% and 31% less, respectively, than plaque harvested from the tap water control teeth. The mean sum of gingivitis scores was about 30 in both experimental groups during the five days but increased in the control groups to 45-50. Authors conclude that, while both solutions were found to minimize the drop in plaque pH after sucrose challenge, they also reduced plaque accumulation on teeth and gingivitis. They also observed that the effect on plaque pH in the sodium hypochlorite group persisted for 24 hours after the last treatment. It has to be emphasized, however, that this study was a pilot study involving a very limited number of college students.

De Nardo et al. (2013) stress that sodium hypochlorite has been used in dentistry for more than a century, in particular for irrigating root canals to disinfect and dissolve tissue. “It does not evoke allergic reactions, is not a mutagenic, carcinogen or teratogen, and has a century-long safety record (Bruch 2007). The American Dental Association Council on Dental Therapeutics has designated 0.1% sodium hypochlorite a ‘mild antiseptic mouth rinse’ and suggests its use for direct application to mucous membranes (American Dental Association 1984).”


American Dental Association. Accepted Dental Therapeutics. Chicago, IL: ADA; 1984. p. 326.

Bruch MK. Toxicity and safety of topical sodium hypochlorite. Contrib Nephrol 2007; 154: 24-38.

De Nardo R, Chiappe V, Gomez M, Romanelli H, Slots J. Effects of 0.05% sodium hypochlorite oral rinse on supragingival biofilm and gingival inflammation. Int Dent J 2012; 62: 208-212.

Lobene RR, Soparkar PM, Hein JW, Quigley GA. A study of the effects of antiseptic agents and a pulsating irrigating device on plaque and gingivitis. J Periodontol 1972; 43: 564-568.

Löe H, Silness J. Periodontal disease in pregnancy. I. Prevalence and severity. Acta Odontol Scand 1963; 21: 533-551.

Löe H, Theilade E, Jensen SB. Experimental gingivitis in man. J Periodontol 1965; 36: 177-187.

Turesky S, Gilmore ND, Glickman I. Reduced plaque formation by the chloromethyl analogue of vitamine C. J Periodontol 1970; 41: 41-43.

Quigley GA, Hein JW. Comparative cleansing efficiency of manual and power brushing. J Am Dent Assoc 1962; 64: 26-29.

20 August 2013 @ 1:45 pm.

Last modified August 21, 2013.



  1. Alfred D. Wyatt, Jr. D.M.D.

    I’m not sure if it has been noted, but when this article reviews the De Nardio paper, there is a typo saying he “describes the effects of 0.05 sodium hypochlorite oral rinse” DeNardio was looking at 0.05%. Reading further into the paragraph, the correction was made, but to those who may not have read the DeNardio paper or abstract, it could be confusing as to which concentration is the correct one.


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