Why Sodium Hypochlorite?
One of the questions I frequently get is: “Why would I recommend sodium hypochlorite as anantimicrobial agent?” Obviously there are some challenges with sodium hypochlorite, primarily taste, and with some patients an increased susceptibility to staining. The best thing I can do is provide you with a little bit of history and my personal experiences.
When I implemented CAMBRA into my practice in 2001, with John Featherstone and Doug Young as my mentors, I started using a regimen of 1 week of Chlorhexidine (CHX) rinse followed by 3 weeks of 0.05% fluoride rinse. That was considered the gold standard at the time for the antimicrobial treatment of dental caries. I used this regimen for high caries risk patients for a couple of years, and at the time I was also culturing patients’ saliva for Mutans streptococci (MS) and Lactobacillus (Lb).
I made a couple of observations during that period.
1. Chlorhexidine is problematic with regard to taste and staining for many patients.
2. Post treatment culture results concerned me.
After a 3 month regimen of the Chlorhexidine followed by the fluoride rinse, the cultures revealed that I had dramatically reduced the Mutans streptococci levels, but for many patients the Lactobacillus levels were either unchanged or had increased significantly to the point that there was one solid mass covering the culture plate. As it turns out, we know that CHX is very effective against MS but has no real effect on Lb.
3. I wasn’t seeing much improvement in decay rates for the people I was using this regimen with.
4. The cultures did not tend to correlate to what I was seeing clinically. So it was a challenging time to sort this all out.
I then turned to Povidone Iodine (PI) as an antimicrobial rinse in the form of Betadine 10%. Now if you haven’t ever rinsed with PI is an experience you won’t soon forget. The list of problems with PI, start with taste; it also stains anything it touches (countertops and clothes). Additionally you can only use it once a month, and you can’t use it for people with shellfish allergies. There was encouraging research using PI on a 2X2 to wipe infants’ mouths, and even wiping primary teeth for very young patients. However, Doug Young tested the PI on young adults at UOP and found no statistical reduction in bacterial load. So after a troubling year of working with PI, it was back to the drawing board.
Jorgen Slots had advocated sodium hypochlorite for years as an antimicrobial agent to reduce bacterial load for treating periodontal disease, and in 2002 published a review article in the Journal of Periodontal Research.1 In the paper he identified 0.1% sodium hypochlorite as a sub-gingival rinse. So at that time I began testing sodium hypochlorite on high caries risk patients. Suddenly I was finding the results in caries reduction I was looking for. The bacterial cultures still didn’t correlate to what I was seeing in the mouth, which prompted me to search for a better biometric, but that’s a good topic for another blog. The first article was followed up in 2005 with another article in the International Dental Journal where the authors stated “0.1- 0.5% sodium hypochlorite for patient self-care. These antiseptics have significantly broader spectra of antimicrobial action, are less likely to induce development of resistant bacteria and adverse host reactions, and are considerably less expensive than commercially available antibiotics in controlled release devises.”2
In 2007 a 3-year independent university based study was conducted on high caries risk school-aged children. In a randomized double blind clinical trial utilizing a standard 0.05% fluoride rinse as a control, the children performed a supervised rinse for 30 seconds each school day, 4 days per week, for the 9- month school year. At the end of two years the 0.05% fluoride rinse demonstrated a 29% reduction in caries incidence, which is consistent with other studies utilizing a similar rinse. The 0.2% sodium hypochlorite/0.05% fluoride/xylitol rinse reduced the caries incidence by 73%. There was no additional reduction in year three. This is consistent with the results I see with my patients.
Since then of course, there have been other articles on the subject, and we routinely use sodium hypochlorite in endodontic therapy to disinfect canals. There have also been several papers published in the meantime identifying other potential issues with using CHX. At OHSU student research examined the use of CHX with young children. They examined 7 children and looked for the different serotypes of MS that they carried in their oral biofilms. There were 31 different serotypes at the beginning of the trial. Then after 1 week of CHX rinses, they re-examined the children at intervals up to one year. They found that all of the children had only 1 remaining serotype, and it was the same one for all of the children. This particular MS serotype was particularly caries pathogenic in the laboratory. It seemed as if the CHX eliminated the lesser cariogenic MS serotypes and selected for the most cariogenic serotype. At the end of 1 year all of the children continued to have only that MS serotype. It is difficult to draw conclusions from this small study, but the results should indicate we re-think the use of CHX as anti-caries agent.
In 2011 The ADA Council on Scientific Affairs published a review and recommendations for non-fluoride anti-caries agents. The recommendations included some evidence for CHX/Thymol varnish every 3 months for root surface decay, but in bold red letters “All other CHX in any form, for any lesion site, for any age: NOT RECOMMENDED.” 3
Fast-forward to December 2013, Jorgen Slots and a group of authors published a 3 month single blinded clinical trial on 30 patients using 0.25% sodium hypochlorite in the test group and water as a control. The patients with gingivitis and minimally treated periodontitis were asked to rinse twice a week. They measured plaque levels at baseline, 2 weeks and 3 months. They found increases of 94% and 29% of plaque free facial surfaces with the sodium hypochlorite and water rinses respectively. Likewise increases of 195% and 30% of plaque free lingual surfaces, and 421% and 29% increases in probing sites with no bleeding on probing. The differences were marked and statistically significant. They concluded:
“A twice-weekly oral rinse with 0.25% sodium hypochlorite produced marked decreases in dental plaque level and bleeding on probing and may constitute a promising new approach to the management of periodontal disease. Long-term controlled studies on the effectiveness of sodium hypochlorite oral rinse are needed and encouraged.”
Based on the evidence, the research literature and my personal clinical experiences, at this point in time, sodium hypochlorite appears to be the most effective anti-caries antimicrobial agent. It does not come without some potential complaints, but it is effective at reducing bacterial load, which is my objective in treating the high risk dental caries patient.