What To Do When The Evidence Is Lacking?

Introduction

You may recall the media storm in 2016 that was precipitated by a report by Jeff Donn from the Associated Press. He wrote there is no solid evidence that flossing is effective. Based on various form of social media it seems that it did not sit well with the dental community. However, Donn was correct. There is no solid evidence for the regular and consistent recommendation of dental floss for interdental cleaning.

Donn did his due diligence and found few systematic reviews on the benefits of flossing. This led him to his conclusion. Many were shocked but they missed the point of the conversation. He never said that we should not recommend dental floss or that it is not effective. What he communicated was that the evidence was lacking and it is something that the dental community needed to address.

This should not have been news to dentists or dental hygienists. The systematic reviews were published in 2006, 2008 and 2012. Of course, many dental professionals have seen the benefits of flossing in their practices. Unfortunately, it is not often enough. The challenge is that patients do not like to floss, do not perform adequate flossing technique, or it is not the ideal choice due to their specific needs or oral conditions.

The message is not that you need to floss but that interdental cleaning is an important part of daily oral hygiene. This is the perfect time to change the mantra from flossing to ‘cleaning between your teeth’. It is long past the time to get the message out about interdental cleaning in a clear and concise way. A summary of the key systematic reviews pertaining to interdental cleaning are listed below for your review.

Systematic Reviews Of Interdental Oral Hygiene Devices

The highest level of evidence is the systematic review. A systematic review summarizes the results of available research papers related to a specific question (Fig. 1). It is a complicated process and authors follow a protocol that involves several steps (Fig. 2). Systematic reviews do not always provide useful information, as they are dependent on available clinical trials. Outcomes may simply be that there is no evidence or the available evidence is limited at best.

Figure 1

Systematic review process diagram. Adapted from Centre for Health Communication and Participation with support from the Australiasian Cochrane Centre. Licensed under a Creative Commons Attributiom: NonCommericial-NoDerivs 3.o Unported License. https://creativecommons.org/licenses/by-nc-nd/3.0/

Figure 2

Process of a systematic review. Adapted from Centre for Health Communication and Participation with support from the
Australiasian Cochrane Centre. Licensed under a Creative Commons Attributiom: NonCommericial-NoDerivs 3.o Unported License.
https://creativecommons.org/licenses/by-nc-nd/3.0/

Dental Floss

Several systematic reviews have been published providing information on different interdental cleaning devices. In some cases the findings showed a significant lack of evidence for devices that have long been considered the standard of care. For instance, dental floss has been recommended globally for over a century and often thought of as the standard of care for interdental cleaning. However, three systematic reviews showed there is a lack of evidence for recommending dental floss as common practice.1-3 It may be beneficial for individuals with excellent oral health and can master the technique. Two of the reviews also showed that there is no evidence that flossing reduces interproximal decay.2,3 In fact, there are no studies on adults in the literature.

Interdental Brushes

Interdental brushes were originally introduced to help patients clean wide interdental spaces. Recently, new designs and smaller sizes of brushes and elastomeric tips/picks have been introduced in the market place. Newer designs have not been systematically reviewed. Researchers have reported that interdental brushes remove more plaque than brushing alone, brushing and flossing, or wood sticks. Differences between the devices for gingival inflammation were either inconclusive or showed no difference.4

The suggestion that interdental brushes are the most effective interproximal cleaning device is premature. Evidence on plaque removal with a lack of evidence for the reduction in inflammation is insufficient. The true measure of an effective treatment or device is the reduction of bleeding. Most of the studies included in systematic reviews were conducted on patients with periodontal disease who had interproximal spaces sufficient to accept the Interdental brush without trauma. Another important point is the lack of consistency as to how many times the brush should be inserted into the space, and in some cases only one site between posterior teeth was included in the data.

Wood Sticks

Eight published studies were included in a systematic review on the use of wood sticks for interproximal cleaning. There was some evidence that wood sticks and brushing was better than brushing alone for the reduction of bleeding. However, there was no difference in plaque or gingivitis scores. There were no differences between wood sticks and dental floss for any clinical parameters. Only one study showed that interdental brushes were better at reducing plaque than wood sticks.5

Water Flosser

Today there are other options for interdental cleaning that are not as well known. A systematic review of using a water flosser and manual brushing compared to brushing alone has been published.6 Seven studies were included from 1971–2000. Two of the studies used devices that delivered high frequency fractionated spurts of water, four studies produced a pulsating single stream of water and one study did not specify the mechanism of action. In these studies, two of the products are not on the market today. When evaluated together the data showed a tendency toward a reduction in bleeding. When the studies were separated by their method of action, the fractioned devices showed no benefit over brushing alone, but the pulsating data showed a significant reduction in bleeding, gingival inflammation and pocket depth. The most widely studied device in this category is the Waterpik Water Flosser.

Waterpik Water Flosser

Water Flosser (Waterpik, Fort Collins, CO) is one the best researched self-care devices on the market. There are 70 published research articles that unequivocally show it is safe and effective to use.7,8 To date there are five randomised controlled trials that compare the Water Flosser to dental floss.9-13 A single-use plaque removal study showed that the WF removed 29% more plaque than dental floss when used with a manual toothbrush.11 Comparisons to dental floss were also conducted with different patients: orthodontic13, implant12 and gingivitis.9,10 Findings included a reduction in gingival inflammation of 52% for gingivitis patients, 26% for orthodontic patients and 145% for implant patients.

In 2009, researchers evaluated the removal of biofilm from the tooth surface using a Water Flosser and scanning electron microscopy.14 The results showed that the Water Flosser removed 99.9% of the biofilm from treated areas. Single use clinical study has shown a 75% reduction of whole mouth plaque and 92% for interproximal areas.14 A Four week study showed a 51% and 77% reduction in whole mouth and interdental plaque respectively.15

The Water Flosser was compared to interdental brushes in two clinical studies. A single use study showed the Water Flosser was 20% more effective than interdental brushes for removing dental plaque.16 In a pilot study the Water Flosser was 56% more effective at reducing gingival bleeding than interdental brushes over a two-week period.17

The Water Flosser has been compared to air floss in four clinical trials.18-21 The Water Flosser consistently demonstrated that it is more effective than an air floss device (Philips Oral Healthcare, Bothell, WA) for removing dental plaque and reducing gingival bleeding and inflammation.

The unique pressure and pulsation combination of the Water Flosser has demonstrated significant reductions in many clinical parameters: gingival bleeding, gingival inflammation, dental plaque, probing pocket depth, subgingival bacteria, pro-inflammatory mediators, calculus formation.

The Water Flosser produces a compression and decompression action at the gingival margin, which efficiently and effectively cleans the subgingival and interdental areas. This is supported in studies that demonstrate that the Water Flosser can reduce the quality and quantity of subgingival microflora up to 6 mm.22,23 No other oral hygiene device has demonstrated this benefit. Collectively, the research shows the unique pressure and pulsation combination of the Water Flosser significantly reduces many clinical parameters and indices leading to improved oral health.

Conclusion

Systematic reviews and meta-analysis are essential to help clinicians make informed decisions. The most critical time spent with a patient is on oral hygiene instruction. It is important to make that time count by being prepared and aware of the current evidence on plaque control and gingival inflammation. Studies that just demonstrate plaque removal but lack evidence for the reduction of gingival inflammation do not provide adequate information.

Take the time with your patients to understand what they expect and value. This will help tailor an oral care regimen that the patient is more likely to perform and the patient will also appreciate the personal focus on their needs. OH

Oral health welcomes this original article.

References:

Berchier CE, Slot DE, Haps S, Van der Weijden GA. The efficacy of dental floss in addition to a toothbrush on plaque and parameters of gingival inflammation: a systematic review. Int J Dent Hygiene 2008; 6:265-279.
Hujoel PP, Cunha-Cruz J, Banting DW, Loesche WJ. Dental flossing and interproximal caries: a systematic review. J Dent Res 2006; 85(4):298-305.
Sambunjak D, Nickerson JW, Poklepovic T et al. Flossing for the management of periodontal diseases and dental caries in adults. Cochrane Database of Systematic Reviews 2011, Issue 12. Art. No.: CD008829. DOI:10.1002/14651858.CD008829.pub2.
Slot DE, Dörfer CE, Van der Weijden GA. The efficacy of interdental brushes on plaque and parameters of periodontal inflammation: a systematic review. Int J Dent Hygiene 2008; 6:253-264.
Hoenderdos NL, Slot DE, Parakevas S, Van der Weijen GA. The efficacy of woodsticks on plaque and gingival inflammation: a systematic review. In J Dent Hygiene 2008; 6:280-289.
Husseini A, Slot DE, Van der Weijden GA. The efficacy of oral irrigation in addition to a toothbrush on plaque and the clinical parameters of periodontal inflammation: a systematic review. Int J Dent Hygiene 2008; 6:304-314.
Jolkovsky DL, Lyle DM. Safety of a water flosser: a literature review. Comp Contin Ed Dent 2015; 36(2):146-149.
Lyle DM. Relevance of the water flosser: 50 years of data. Comp Contin Ed Dent 2012; 33(4):2-5.
Barnes CM, Russell CM, Reinhardt RA, Payne JB, Lyle DM. Comparison of irrigation to floss as an adjunct to tooth brushing: effect on bleeding, gingivitis, and supragingival plaque. J Clin Dent 2005; 16:71-77.
Rosema NAM, Hennequin-Hoenderdos NL, Berchier CD, Slot DC, Lyle DM, van der Weijden GA. The effect of different interdental cleaning devices on gingival bleeding. J Int Acad Periodontol 2011; 13:2-10.
Goyal CR, Lyle, DM, Qaqish JG, Schuller R. Evaluation of the plaque removal efficacy of a water flosser compared to string floss in adults after a single use. J Clin Dent. 2013; 24(2):37-42.
Magnuson B, Harsono M, Stark PC, Lyle DM, Kugel G, Perry R. Comparison of the effect of two interdental cleaning devices around implants on the reduction of bleeding: a 30-day randomized clinical trial. Comp Contin Ed Dent. 2013; 34(Special Issue No. 8):2-7.
Sharma NC, Lyle DM, Qaqish JG, Galustians J, Schuller R. Effect of a dental water jet with orthodontic tip on plaque and bleeding in adolescent patients with fixed orthodontic appliances. Am J Orthod Dentofacial Orthop 2008; 133:565-571.
Gorur A, Lyle DM, Schaudinn C, Costerton JW. Biofilm removal with a dental water jet. Comp Contin Dent Ed 2009; 30(Special Issue 1):1-6.
Sharma NC, Lyle DM, Qaqish JG, Schuller R. Comparison of two power interdental cleaning devices on reduction of gingivitis. J Clin Dent 2012; 23:22-26.
Lyle DM, Goyal CR, Qaqish JG, Schuller R. Comparison of water flosser and interdental brush on plaque removal: a single-use pilot study. J Clin Dent 2016; 27:23-26.
Goyal CR, Lyle DM, Qaqish JG, Schuller R. Comparison of water flosser and interdental brush on reduction of gingival bleeding and plaque: a randomized controlled pilot study. J Clin Dent 2016; 27:61-65.
Sharma NC, Lyle DM, Qaqish JG, Schuller R. Comparison of two power interdental cleaning devices on plaque removal. J Clin Dent 2012; 23:17-21.
Sharma NC, Lyle DM, Qaqish JG, Schuller R. Comparison of two power interdental cleaning devices on the reduction of gingivitis. J Clin Dent 2012; 23:22-26.
Goyal CR, Lyle DM, Qaqish JG, Schuller R. Efficacy of two interdental cleaning devices on clinical signs of inflammation: a four-week randomized controlled trial. J Clin Dent 2015; 26:55-60.
Goyal CR, Lyle DM, Qaqish JG, Schuller R. Effectiveness of two interdental cleaning devices on clinical signs of inflammation. J Dent Res 2017; 96(Spec Iss A): 0885.
Cobb CM, Rodgers RL, Killoy WJ. Ultrastructural examination of human periodontal pockets following the use of an oral irrigation device in vivo. J Periodontol. 1988; 59(3):155-163.
Drisko C, White C, Killoy W, Mayberry WE. Comparison of dark-field microscopy and a flagella stain for monitoring the effect of a Water Pik on bacterial motility. J Periodontol, 1987; 58(6):381-386.

Deborah is an experienced clinician, educator, speaker and researcher. She has written numerous textbook chapters, published 55+ articles and research manuscripts. Deborah has presented over 100 continuing education courses globally with an emphasis on critical thinking and evidence-based practice. She is also an editorial board member for the Journal of Dental Hygiene and International Journal of Dental Hygiene. Deborah is the Director of Professional and Clinical Affairs for Water Pik, Inc.