Is household bleach an effective biofilm killer

Nov. 12, 2013
Diana Nyad reminds us that you are never too old to achieve your dreams. After swimming 110 miles from Cuba, she arrived in Key West, Fla., with swollen lips and tongue ...

By Lynne Slim, RDH, BSDH, MSDH

Diana Nyad reminds us that you are never too old to achieve your dreams. After swimming 110 miles from Cuba, she arrived in Key West, Fla., with swollen lips and tongue that her doctors feared would make it difficult for her to breathe. As a dental hygienist who pays close attention to any mention of the oral cavity in a news story, I was eager to see how easy it would be for her to speak to the press. As with everything else she does, she spoke with aplomb.

Several years ago, I travelled to Southern California to hear Professor Jorgen Slots lecture on anti-infective agents in periodontal treatment, especially a mouth rinse containing one part sodium hypochlorite (household bleach) to 20 parts water. As required by this educational seminar, I rinsed for 30 seconds with the solution, and my tongue was tingling. So I can only imagine what Diana Nyad experienced on her 53-hour ocean voyage.


Other columns by Lynne Slim


Some clinicians, including periodontists and dental hygienists, have dismissed Slots' "signature" mouth rinse. But it has recently resurfaced again in the periodontal literature and on chat groups for discussion.

It bears repeating that periodontal disease (gingivitis and periodontitis) develops through inflammatory processes induced by a pathogenic microbial biofilm. This fundamental discovery of a strong association between microbial biofilms and gingival inflammation was first reported by Loe in his classic experimental gingivitis study in 1965.

Sodium hypochlorite (NaClO) is a highly active cytotoxic oxidant that is among the most potent antiseptic or disinfectant against bacteria, fungi, and viruses.1 Because it occurs naturally in human neutrophils and monocytes and macrophages, it doesn't cause allergic reactions. But it has been designated an asthma-causing agent by the Association of Occupational and Environmental Clinics among occupationally exposed workers.2 NaClO has a century-long safety record and is not a mutagen, carcinogen, or teratogen.3

Slots authored an article in 2012 titled "Low Cost Periodontal Therapy" and points out that successful periodontal care of low-income populations should be based on affordable professional therapy and self-care techniques with proven efficacy and safety.4 Unfortunately, he writes that most models of prevention and treatment of periodontal disease have not been adequately tested or compared in controlled studies. Management of periodontal disease in these individuals is especially understudied and sufficient manpower with appropriate skills to treat this underserved population group is inadequate to meet their needs.

He highlights cost-concerns and the ever threatening global increase of antibiotic-resistant bacteria, and he suggests that there is considerable interest in using less expensive, safe, and highly bactericidal/virucidal antiseptics in periodontal therapy. He recommends the broad use of antiseptics in periodontal treatment, including povidone-iodine, dilute sodium hypochlorite and chlorhexidine gluconate because of their wide spectra of microbial and virucidal activity -- even when used for a few minutes or when used adjunctively with subgingival scaling. Slots also mentions a couple of limitations to the use of antiseptics: the inability to eradicate microbes in gingival tissues, and the risk of cytotoxicity and hypersensitivity reactions.4

Sodium hypochlorite rinsing (0.05%) exerts broad antimicrobial activity against experimental oral biofilms.4 Bleach can reach bacteria in biofilms because it actually dissolves away (oxidizes) the polysaccharide matrix.5 Hydrogen peroxide (another oxidizing agent) does this effectively, too. Oxidizing biocides such as bleach and hydrogen peroxide dissolve the biofilm matrix, exposing the bacteria to the biocide.5

In reviewing the literature on sodium hypochlorite as an antimicrobial adjunct, I found very few articles, and one was a small pilot study from Lobene et al. (1972). Lobene conducted a pilot study involving six college students who used an oral irrigation device with 1% hydrogen peroxide and 0.5% bleach. Plaque mass harvested from these solutions resulted in a 47% plaque mass reduction for bleach and 31% reduction for hydrogen peroxide compared to a water-control.

What prompted me to write about this topic now was a new article by De Nardo et al. (2012) that reported results of a somewhat larger study. The authors published the results of a 0.05 percent sodium hypochlorite oral rinse on supragingival plaque/biofilm and gingival inflammation.6 Subjects were administered twice-daily a sodium hypochlorite oral rinse for 21 days. A 10 % sodium hypochlorite stock solution was purchased from a chemical drugstore, and the 0.05% working solution was created by mixing 5 ml of the stock solution with 995 ml of distilled water. A fresh solution was made every 24 hours and stored in dark, disposable bottles.

The study was a randomized, placebo-controlled, investigator-blind parallel group trial with 40 male inmates from Argentina who were required to have at least 20 natural teeth, healthy gingiva, or slight periodontitis with clinical attachment loss ≤ 2 mm. Subjects received periodontal treatment over a pre-experimental period of 30 days in order to establish gingival health which included professional scaling, polishing, interdental cleaning, and self-care motivational sessions with instructions in flossing and Bass toothbrushing technique.

After subjects withdrew from any oral hygiene measures, they were randomly assigned to either rinsing twice daily (for 21 days) with 15 ml of the 0.05% sodium hypochlorite for 60 seconds, or to rinse for 60 seconds with 15 ml of distilled water. Clinical assessment included a plaque index, gingival index, and the presence or absence of bleeding on probing. Clinical measurements and photographs were taken every seven days for 21 days with appropriate intra-examiner calibration.

Forty of the 44 enrolled inmates completed the study and extrinsic brown tooth stains appeared in 100% of the subjects in the sodium hypochlorite group and in 35% of the water rinse group. (Subjects could smoke up to 10 cigarettes a day.) Examination of the oral mucosa revealed redness of the tongue in 35% of subjects using sodium hypochlorite. All participants in the bleach group noted the "bleach taste," and 85% described the rinse as tolerable (45% reported a burning sensation). Subjects in the sodium hypochlorite group reported a cleaner mouth and less bad breath despite not brushing teeth for 21 days.

Compared with the water rinse, the bleach group demonstrated 48.1% reduction in scores on the plaque index, 52.4% reduction on the gingival index, and 39.1% reduction in the percentage of sites that bled on probing. These results were all highly significant and clinically relevant. The De Nardo group concluded that 0.05% sodium hypochlorite as a mouthrinse can benefit all periodontal patients, emphasizing that its low price makes it particularly appropriate for individuals with low incomes.6

For individuals with low incomes, such as prison inmates, 0.05% sodium hypochlorite as a twice-daily mouthrinse appears to be safe and effective in reducing supragingival biofilms and gingival inflammation. From a practical standpoint, twice daily rinsing with a mouthrinse that tastes only "tolerable" and can cause a burning sensation on the tongue may not be appropriate to recommend to most individuals. Dental hygienists must weigh the pros and cons in making this self-care recommendation. Recommendations for the use of household bleach, including a specific concentration, in an oral irrigator has not yet been adequately studied.


3. Bruch MK. Toxicity and safety of topical sodium hypochlorite. Contrib Nephrol 2007; 154: 24-38.
4. Slots J. Low-cost periodontal therapy. Periodontol 2000 2012; 60: 110-137.
6. 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.
7. De Nardo et al. Effects of 0.05% sodium hypochlorite oral rinse on supragingival biofilm and gingival inflammation. Int Dent J 2012; 62: 208-212.

LYNNE SLIM, RDH, BSDH, MSDH, is an award-winning writer who has published extensively in dental/dental hygiene journals. Lynne is the CEO of Perio C Dent, a dental practice management company that specializes in the incorporation of conservative periodontal therapy into the hygiene department of dental practices. Lynne is also the owner and moderator of the periotherapist yahoo group: Lynne speaks on the topic of conservative periodontal therapy and other dental hygiene-related topics. She can be reached at [email protected] or

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