An update on bleach swishing: Reviewing the literature on diluted bleach rinsing

June 12, 2015
Sometimes my analogies are a bit of a stretch, but it's a good way to introduce a controversial topic.


Sometimes my analogies are a bit of a stretch, but it's a good way to introduce a controversial topic. Like many women around the globe, I couldn't get enough of the trilogy Fifty Shades of Grey. I pretty much ignored everyone around me, including my dachshunds, until the very last page. What fascinated me most about the book, however, was the entire Fifty Shades phenomenon, and I even read somewhere that there's a magazine devoted to this obsession.

A phenomenon in dentistry worth discussing is the practice of using diluted bleach as a mouth rinse. It appears to be more common in Southern California where the Danish periodontist and professor, Dr. Jorgen Slots, resides (but I may be wrong in making this assumption). In chatting yesterday with a good friend, Renee Marchant, RDH, from Northern California, I asked her if swishing or irrigating with a diluted bleach mixture was popular there. She indicated it was not and cited "bad bleach taste" as an issue that prevents patients from adopting it in their weekly oral hygiene regimen.


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I wrote about this topic in a November 2013 RDH column titled "Is household bleach an effective biofilm killer?" I thought I would update readers on new research to support or question its use. In addition, I emailed Dr. Jorgen Slots, and he sent me a few publications that were published last year.

I'm an adventurous soul, and I use the diluted bleach mixture in my own mouth. I follow the instructions given to me by Dr. Slots: put ½ teaspoon of regular bleach in a four-ounce glass of water, and use a fresh dilution before each use. Rinse for 30 seconds and wait 10 minutes to rinse with water or eat.

I modify Slots' formula slightly by adding it to my oral irrigator or AirFloss, and he recommends rinsing with the mixture two to three times a week.

Dr. Slots also emphasizes tongue cleaning, and he reports that the bleach mixture kills 99% of bacteria compared to 50% with a commercially available mouthwash. Dr. Slots also reports that more frequent rinsing with the diluted bleach solution may produce a brown-black discoloration of the teeth.1

As a dedicated and persistent evidence-based dentistry sleuth, I like to evaluate claims by researchers such as Dr. Slots who says bleach as an oral rinse is the most effective agent for killing bacteria, viruses, fungi, and spores. Just as important, even if this particular rinse is an effective anti-infective agent, what are the documented oral health outcomes?

Dr. Slots likes to write about the types and sources of biofilm microorganisms, including viruses, and he worries about the infectious potential of bacteria and viruses (cross-contamination by salivary transfer).2

He continues to offer suggestions for antimicrobial treatment of the entire oral cavity, not only of dental biofilms attached to teeth. He believes that all periodontal patients can benefit from a sodium hypochlorite antiseptic, which he reports is effective against bacteria and herpes viruses. He strongly advocates the professional administration of:

• A battery of antimicrobial agents such as chlorhexidine or diluted sodium hypochlorite (bleach) for general disinfection of the oral cavity

• Povidone-iodine for subgingival irrigation and systemic antibiotics to reach microorganisms within periodontal tissues and in hard-to-reach subgingival sites

In addition, he believes a follow-up maintenance program should have a strong anti-infective emphasis and may include patient-administered subgingival irrigation with diluted sodium hypochlorite or chlorhexidine two to three times a week.2

The hardest part about my writing is searching the literature on for randomized controlled trials and systematic reviews of such trials. They are considered the gold standard for assessing the effectiveness of interventions. I was batting close to zero in my search. But, as luck would have it, I searched again and found one small clinical trial on PubMed and an analysis of two small pilot studies by a well-respected professor of periodontology, Hans-Peter Müller, who I email occasionally and who has a good grasp of research methodology in periodontics.

The effects of 0.05% sodium hypochlorite oral rinse on supragingival biofilm and gingivitis were evaluated in a small prison population (40 inmates).3 After a preparatory period to obtain a plaque- and gingivitis-free dentition, tooth brushing was eliminated and inmates instead were randomly assigned to either rinse with 15 ml of distilled water or 15 ml of the diluted bleach solution twice a day for 21 days.

Clinical outcomes were assessed using the Quigley-Hein Plaque Index (QHPI), the Löe and Silness Gingival Index (L&SGI), and bleeding on probing. At day 21, the average QHPI score increased to 3.82 in the water-only rinse group and 1.98 in the sodium hypochlorite rinse group. The average L&SGI score increased to 2.1 in the water rinse group and 1.0 in the sodium hypochlorite rinse group, and the average percentage of sites that bled on probing had increased to 93.1% in the water-only rinse group and 56.7% in the sodium hypochlorite rinse group. Differences were statistically significant (P = 0.001). A brown extrinsic tooth stain along the gingival margin appeared in 100% of participants in the sodium hypochlorite rinse group and in 35.0% of participants in the water-only rinse group.3

In his February 2015 blog, Dr. Müller reported on a 2014 pilot study that resulted in two papers.4,5,6 In one of the papers, 15 test patients with untreated periodontitis were randomized into one of two groups: one group rinsed twice a week for three months with 0.25% sodium hypochlorite (one teaspoon to four ounces of water) and the other rinsed twice a week for three months with water only.

At baseline and after two weeks, patients received oral hygiene instructions, and pockets were irrigated with either 0.25% sodium hypochlorite or water and no supra- or subgingival scaling was performed. Only 12 patients (40% of subjects) completed the three-month study! The sodium hypochlorite rinse group and the water rinse group, respectively, showed increases from baseline to three months of 94% and 29% (3.2-fold difference) in plaque-free facial surfaces, of 195% and 30% (6.5-fold difference) in plaque-free lingual surfaces, and of 421% and 29% (14.5-fold difference) in number of teeth with no bleeding on probing.

The differences in clinical improvement between the sodium hypochlorite rinse group and the water rinse group were statistically significant. No adverse events were identified in any of the study patients, except for minor complaints about the taste of bleach.

The second paper evaluated the potential of gingival bleeding on probing to serve as a predictor of future periodontal breakdown and evaluate the effects of a 0.25% sodium hypochlorite rinse on gingival bleeding. Only seven patients with periodontitis rinsed with the sodium hypochlorite mixture and five periodontitis patients rinsed with water. Results showed that twice-weekly oral rinsing with dilute bleach (0.25%) produced a significant reduction in bleeding on probing, even in deep, unscaled periodontal pockets. But Dr. Müller states that the authors analyzed their data in a way that inflates p-values and results in spurious (inaccurate) study conclusions.

Diluted bleach, like Fifty Shades of Grey, is a phenomenon and maybe even a bit of an obsession for some folks like Dr. Slots. Rinsing/irrigating with diluted bleach as an inexpensive antiseptic agent - despite the awful taste and lack of supporting data - is a practice that can be recommended for patient use if its effectiveness compared to an antiseptic such as chlorhexidine (with plenty of supportive data) isn't an issue for you. Be honest with your patients, however, and tell them that, to date, there are only three small pilot studies that have compared rinsing with water to a diluted bleach mixture. Small studies, like those described above, are unreliable for a number of reasons and should be replicated with larger, randomized clinical trials. RDH


2. Slots J, Slots H. Bacterial and viral pathogens in saliva: disease

relationship and infection risk. Periodontology 2000, Vol. 55, 2011, 48-69.

3. 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 Aug; 62(4): 208-212.
5. Galvan M, Gonzalez S, Cohen CL, Alonaizan FA, Chen CT-L, Rich SK, Slots J. Periodontal effects of 0.25% sodium hypochlorite twice-weekly oral rinse. A pilot study. J Periodont Res 2014; 49: 696-702.
6. Gonzalez S, Cohen CL, Galvan M, Alonaizan FA, Rich SK, Slots J. Gingival bleeding on probing: relationship to change in periodontal pocket depth and effect of sodium hypochlorite oral rinse. J Periodont Res 2014.

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 Evidence-Based Dental Hygiene Group (EBDH) on LinkedIn. Evidence-based periodontal therapy will be part of the group's focus, and Lynne enjoys mentoring dental hygienists in EBDH. She can be reached at [email protected] or