Dental school graduates from the 60s, 70s, and 80s have probably heard of the “Waterpik”, but ask them to tell you what it does or if it is effective, and the common answer is “I don’t know” or “it is not very effective for removing plaque”. Graduates after 2000 may not even know what this technology is or what it does.
The hydrodynamic therapy action of an oral irrigator is not a ‘new’ concept to the dental profession. The innovations lie in the improved understanding of the pathogenesis of oral disease, the role of plaque as a biofilm, and the application of clinical evidence to clinical decision-making. Recent and ongoing research and applications have shown that the oral irrigator is a self-care product that warrants attention in the 21st century.
The original oral irrigator (known as a dental water jet (Fig. 1), and more recently a water flosser (Fig. 2) was developed by Dr. Gerald Moyer, a Fort Collins, CO dentist, and Dr. John Mattingly, a hydraulic engineer at Colorado State University. Dr. Moyer was looking for a product that could clean areas of the oral cavity that are not readily accessible by traditional methods such as tooth brushing and dental flossing. Together they designed a device that provided a controllable, pulsating water stream for the targeted delivery of a solution and the self-cleansing of inaccessible areas by the patient. The current terminology, “water flosser”, will be used throughout this article.
The water flosser delivers a pulsating stream of water or other solution that results in successive compression and decompression phases of the gingival tissue (Fig. 3).1 The solution strikes the tooth at the gingival margin, the impact zone, and is deflected subgingivally and interdentally, the flushing zone (Fig. 4). It was anecdotally believed that the water flosser was simply flushing out debris without removing plaque or having a positive impact on oral health. However, as early as 1969, studies were reporting significant plaque and calculus reductions for groups using the water flosser.2,3 More recently, significant plaque reduction has been demonstrated in studies with subjects who had mild to moderate gingivitis,4 periodontitis,5 orthodontic appliances,6 and diabetes.7
The above studies used the traditional validated plaque indices which provide a 1-dimensional perspective; the plaque’s presence is determined by disclosing solution. In 2009, Dr. Costerton and his team took this a step further to evaluate the removal of biofilm from the tooth surfaces using a water flosser. This ex-vivo study utilized periodontally involved teeth that were extracted and inoculated with saliva to grow new biofilm over existing deposits. The teeth were treated with a water flosser for 3-seconds at medium pressure and then prepared and viewed under a scanning electron microscope. The removal of biofilm was evident as seen in Figure 3, with almost 100% removal from treated areas.8
SELF-CARE TECHNOLOGY
Brushing is considered the first line of defense for maintaining good oral hygiene. Some power brushes are quite sophisticated; they help the user know when to change quadrants, when the two minutes brushing time is reached, and how the user is doing. They offer power selections that include cleaning action, massaging action, or a gentle stroke for sensitive areas. There are different bristle configurations, brush head sizes and designs, and angles and contours for cleaning the line angles, pits, fissures and posterior regions. Careful analysis determines the individual recommendation of the right toothbrush for each patient. Tooth brushing targets only supragingival plaque, however. Numerous studies have indicated that significant plaque can remain after brushing.9 And all tooth brushing, whether power or manual, fails to clean interdentally, an area that the patient must address separately. It can be argued that interdental cleaning should be the first step since that is the area where periodontal disease and infection are at a higher risk.
While dental floss is not a state-of-the-art technology, it is still considered the first choice for interdental cleaning among dental professionals. A major problem is that patients don’t like to floss,10,11 tend to avoid the practice, and often demonstrate a less-than-adequate technique.12 Dentists and dental hygienists need to find alternative methods to accomplish interdental cleaning.
There are many products available that are designed or marketed to clean between the teeth and to motivate individuals to perform this task; how effective are they, and can they be used easily by most individuals? Interdental brushes have been shown to reduce plaque and gingivitis,13 but require a large enough embrasure space for access. Even the smallest designs may not fit into all interdental spaces or effectively clean the proximal surface concavities of the teeth. Floss holders are designed to make it easier to use floss, but do not eliminate all the dexterity challenges that patients face. Wooden sticks,14 rubber tips, and toothpicks are not interdental cleaners.
The recent advent of “water flosser” as a descriptor is based on clinical findings from 3 studies (Table 1). The first study in this group was published in 2005, and demonstrated that the water flosser with a classic jet tip, plus either a power toothbrush or a manual toothbrush, was significantly better at reducing bleeding and gingivitis when compared to a manual toothbrush and string floss.15 This was followed by a 2008 study that compared the efficacy of a water flosser with an orthodontic tip (Figure 5) and manual toothbrush to manual toothbrush and string floss in 11 – 17 year olds with fixed orthodontics.16 The water flosser group had significantly reduced plaque and bleeding over 4-weeks compared to string floss group. The most recent study published in 2011 found that the water flosser with either the classic jet tip or a tip with individual tufts of bristles was up to twice as effective as dental floss in as little as two weeks. The differences between the tips and floss were even more dramatic at four-weeks.17
HOW DOES A WATER FLOSSER STAND OUT FROM OTHER SELF-CARE PRODUCTS?
The documented research on water flossers is extensive, spanning over 50 years. These studies were designed to address new developments in dentistry. The links between periodontal disease and systemic disease have been studied extensively and reported in the literature; some associations are very strong while others are less conclusive. It is well known that people living with diabetes have an increased risk of periodontal disease that can start earlier and lead to more severe complications in both children and adults. Controlling oral inflammation is important and may be more difficult to accomplish than in non-diabetic individuals. A water flosser was compared to traditional oral hygiene in a cohort of type 1 or type 2 diabetic subjects over 3 months. The group that used the water flosser had significantly better improvements in gingivitis, plaque, and bleeding on probing compared to the group that continued with traditional oral hygiene methods.7
Studies between 1990 and 2000 continued to show the benefits of a water flosser in reducing bleeding, gingivitis, and plaque.18-21 Some of the researchers proposed that the significant results from using a water flosser were associated with a change in the host response. With a new focus on host inflammatory modulation a randomized controlled study was conducted comparing routine oral hygiene to routine oral hygiene plus a water flosser.5 The investigators used traditional indices of bleeding, gingivitis and plaque, but also measured pro-inflammatory mediator interleukin-1ß and prostaglandin E2, anti-inflammatory mediator interleukin-10, and interferon gamma, a cytokine key in killing bacteria. The study results showed the water flosser group had a significant reduction in plaque, bleeding, and gi
ngivitis indices plus probing depth compared to the control group. The cytokine profile was changed in the water flosser group, showing a decrease in the pro-inflammatory mediators and an increase in the anti-inflammatory mediators. Since the measurements were taken from gingival crevicular fluid, the researchers prevented a dilution effect by waiting 8 hours after the subjects used the water flosser. Key findings include:
• Both groups reduced plaque biofilm from baseline but only the water flosser group reduced the inflammatory mediator IL-1ß.
• The reduction of bleeding on probing correlated with the reduction of IL-1ß, not the reduction of plaque.
• The selective reduction of pro-inflammatory mediators demonstrates a modulation effect.
In the diabetes study mentioned above, the investigators measured the serum cytokine profile of the subjects. Over the 3 months of the study, the test group that used the water flosser showed significant reductions in IL-1ß and PGE2.7
CONCLUSION
The water flosser has an extensive body of evidence that demonstrates its safety and efficacy with multiple patients and different oral care needs; e.g. gingivitis, orthodontic, implant, crown and bridge, individuals in periodontal maintenance programs, and particularly those with good oral health. Studies in the past decade have addressed new areas such as host response, impact on systemic health, and the effect on biofilm at the microscopic level. The water flosser has the ability to provide individuals an easy and effective way to maintain good oral health by accessing the areas that are not readily reachable and cleansable by traditional methods.
Not all oral irrigators, dental water jets, or water flossers have the same combination of pulsations and pressure. The overwhelming majority of studies have been done using the Waterpik Water Flosser. Dental professionals need to evaluate the evidence for each specific product as studies are not transferable between technologies and manufacturers. OH
Deborah M. Lyle, RDH, BSc, MS is a lifelong member of ADHA, having served on the Council on Education and Task Force for Clinical Practice Guidelines, and chaired the Task Force for the ADHP curriculum development. A member of AADR/IADR and IFDH, she serves on the JDH editorial review board and is chair of the Council on Research. She is director of professional and clinical affairs at Water Pik, Inc.
Oral Health welcomes this original article.
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