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Thank you to all the OHU Graduates who wrote about the subject of interdental-cleaning. They have demonstrated that when answering questions about 'flossing', the best approach is Action Research. They reflect on why certain approaches may not be effective in their specific environment or on their patients and develop a plan to solve these problems. This is a continuous process and all our graduates can utilise these new learned skills throughout their careers, both formally and informally. The other benefit of Action Research is that not only are all our graduates adding to the pool of dental hygiene generated research but as it grows, the knowledge created becomes greater. 

Does Flossing reduce gum disease and tooth decay?

Cochrane is considered the most reliable and trusted source of evidence in the health care sector. When looking at the evidence for flossing in addition to brushing to prevent gum disease and tooth decay, they concluded that, “There was some evidence from twelve studies that flossing in addition to toothbrushing reduces gingivitis compares to toothbrushing alone. There is weak, very unreliable evidence from 10 studies that flossing plus toothbrushing may be associated with a small reduction in plaque at 1 and 3 months. No studies reported the effectiveness of flossing plus toothbrushing for preventing dental caries.” They went onto discuss the trials were of poor quality and conclusions must be viewed as unreliable.


The reason Cochrane is considered the gold standard of evidence is that they are so robust in their examination of the research process and methodology. The positive side to this is that it protects consumers and also when Cochrane states there is good evidence for something, we can be sure that is a correct statement.


What do we do when they state that the trials were of poor quality? How do we create a study to prove that flossing in addition to toothbrushing prevents or doesn’t prevent gum disease and tooth decay where we can be 100% sure of the results? How can we be sure that all the research participants in the flossing group are compliant in the research and also that they are all flossing with the same technique? How could we be sure that the non-flossers in a research study aren’t doing some form of interdental cleaning? The answer is, that it would be extremely difficult and it would be prudent to look at alternative research methodologies that are more suitable to determining an answer to the above question.


Action Research is first person research where clinicians look to solve problems in their own environments and on their own patients. This can become very powerful when outcomes of multiple studies are combined. We recently published fourteen of our graduate action research projects related to ‘flossing’. They can all be viewed in the OHU Action Research Library here.


Having read through all of the above studies, I can conclude that the topic of flossing is far more complex because we are not simply asking our patients to pop a pill. We are asking them to carry out a task that requires knowledge acquisition, a certain amount of manual dexterity and a change in behavior. Interestingly, all these three subjects would be topics more suitable to qualitative research, not the quantitative research preferred by Cochrane that measures statistics and numbers.


In addition our researchers discovered that the mantra of ‘brush & floss’ isn’t necessarily the best approach. Whereas it is just as important to clean the two interdental surfaces of each tooth as the other three, there are several alternative methods that are just as effective.
These methods are water flossing in its various guises, soft (plastic) picks, and bottle brushes, which are all at least as effective as string flossing and in most cases requiring less manual dexterity. All of these three alternatives were likely to see greater patient compliance.
Patient compliance and behavior change were the biggest challenges to our researchers and when a technique such as ‘OARS’ (Open questions, Affirming, Reflecting & Summarizing) was used, patient compliance was more likely.

It can be argued that an experienced hygienist will be able to suggest the best interdental cleaning method by combining the dexterity of the patient, examining the complexity of patient anatomy and overall heath of the mouth. Our researchers discovered that involving the patient in this decision making process and allowing them to make the final decision will again lead to better compliance as will personally following up with the patient at a later date.

The final two outcomes might be useful to future researchers. When looking to discover the reasons why some patients comply with interdental cleaning and others do not, we are better looking for answers by asking our compliant patients what made them comply rather than asking why our non-compliant patients didn’t comply.

Patients who are able to demonstrate behavior change for a month are more likely to change permanently as they begin to see positive health changes, which reinforces this positive change.


Finally, going back to the original Cochrane review. It states, “It is assumed that removing plaque will prevent gum disease and tooth decay.” We all know that the two diseases are far more complex than this and therein maybe an even greater problem when creating a study to determine whether flossing reduces gum disease and tooth decay. Some of our students are currently looking beyond plaque removal to reduce these diseases. Look out for these future projects at the above link in our action research library.


Tim Ives RDH, BSc (Hons), MA Med Ed, FHEA.