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Oral Irrigation

by Denise Parker, RDH

Recently, there has been a renewed interest in oral irrigation. Numerous studies have supported the hypothesis that daily irrigation with a pulsed water-jet device improves oral health. Maximum benefit appears to be achieved with initial to moderate periodontal patients whose traditional mechanical methods of oral hygiene may be less than ideal. There have also been studies evaluating the efficacy of different antimicrobial agents added to the irrigation unit's reservoir. These studies have met with varying results, and the literature will be examined to determine current recommendations and expected clinical outcomes. Another area of research is the professional delivery of antimicrobial agents. The most promising agents and techniques for delivering antimicrobial agents in the dental office will be reviewed to enable the clinician to make informed decisions regarding patient therapy.

In 1962, the Waterpik® oral irrigator was introduced as a homecare aid to help with removal of plaque and debris. Early studies showed a reduction in gingivitis but not in the plaque (biofilm) index. This led to confusion as clinicians felt that if plaque was not mechanically removed, then the Waterpik oral irrigator was not an effective homecare device. For many years, the oral irrigation device was reserved for orthodontic patients and for patients with food impaction or tooth positioning problems. Currently, research has focused on plaque alteration and host modulation. One of the areas that researchers focused on in the past, was the possibility of oral irrigation forcing bacteria into the blood stream, where it could cause infection or damage to bodily organs. Research has found little evidence to suggest that daily irrigation causes significant bacteremia, at least not more than other oral hygiene practices such as, toothbrushing or flossing. In 1988, Cobb found that irrigated areas reduced pathogenic bacteria up to 6 mm and was non-injurious to the tissue. In fact, the risk of bacteremia is significantly higher in those individuals who have poor oral hygiene, thus controlling oral infection is of utmost importance in reducing the incidence of bacteremia. Studies have shown that using an oral irrigation device can substantially improve tissue health and thus can be an effective tool for daily use.

The primary purpose of oral irrigation is to reduce harmful bacteria and therefore the risk and severity of periodontal disease. Studies have shown that daily oral irrigation has the potential to suppress periodontal pathogens located within the pocket. Oral irrigation has demonstrated a reduction in proinflammatory mediators. Periodontal disease causing bacteria cause an increase in cytokine levels, which leads to bone resorption. Daily oral irrigation leads to a reduction in pro-inflammatory cytokines that leads to a slight, but significant, improvement in mild to moderate periodontal disease. In addition, oral irrigation has demonstrated a significant reduction in bleeding, gingivitis, periodontal pathogens and probing depths. The reduction in probing depth was minimal and may not be clinically relevant.. Thus it appears that oral irrigation is a useful adjunct in suppressing and controlling periodontal disease.

Patients who may benefit from oral irrigation include those with orthodontic appliances, implants, crown and bridge, diabetes, periodontal maintenance, gingivitis and those whose traditional oral hygiene may be less than ideal.

Daily irrigation

There are several types of oral irrigators, but like all self-care devices they require daily use for maximum efficacy. The most common type for home use is a pulsed flow irrigator. There are also direct flow or steady stream irrigators. Most of the studies completed on oral irrigation were done using pulsed irrigators by Waterpik Technologies. Results cannot be extrapolated to other pulsating devices or direct flow irrigators. Another type or oral irrigator, is the pulsed flow, magnetized irrigator. The hypothesis is that the charged water decreases calculus formation as well as achieves the benefits found with non-magnetic irrigators. Two studies have shown a decrease in calculus on lower anterior teeth only with magnetization but no greater reductions in bleeding or gingivitis.

There is also a type of irrigator that incorporates micro-bubbles of air into the water stream. These bubbles produced by the Braun Oral B OxyJet, are designed to enhance plaque disruption and thereby reduce gingival inflammation. However, in a study by Frascella et. al. the OxyJet was found to be safe but there was not difference in the reduction of clinical parameters compared to the non-irrigation group.

There are several tips for use on the market today. The most prevalent is the jet tip or standard tip, which is designed for supragingival placement. This standard tip can deliver an irrigant to an average of 50 percent of the pocket depth. Another tip that can be very helpful for periodontal patients is the Pik Pocket™ subgingival irrigation tip by Waterpik Technologies. This is a soft latex free rubber tip designed to fit Waterpik oral irrigators. The Pik Pocket tip has been found to penetrate 90 percent of the depth of the pocket. This can be a very effective tool to flush out periodontal pockets or to deliver antimicrobials to the depth of the pocket. Ora-tec also manufactures a uniquely designed tip that can be used for both standard and sulcus irrigation with their Via-Jet home irrigator. In addition, a few manufacturers supply cannula tips to be used with their irrigators. Cannula tips have not been tested for safety or efficacy for home use by the patient.

There are several reasons why daily irrigation is beneficial for oral health. One reason is to remove unattached plaque and dilute toxins. A second reason is to control gingivitis, especially in those patients who do not or cannot perform adequate interproximal hygiene. The oral irrigator appears to "pick up the slack" in patients whose home care is less than ideal. A third reason that oral irrigation is beneficial is that it can improve bad breath by reducing the pathogenic bacteria or by using a specially designed tongue cleaner attachment. This can be an effective tool in motivating patients to irrigate. For patients who do not receive the desired result with traditional home care methods, irrigation can be most effective in helping them to gain good oral health.

Patients should be instructed to direct the tip at a 90º angle to the long axis of the tooth, and about 3 mm away from the gingival margin. Then, follow the gingival margin and stop at each interproximal area for five or six seconds, irrigating both the lingual and buccal aspect of the teeth. For moderate to advanced periodontal disease, daily subgingival irrigation can be very beneficial in helping to achieve adequate home care.

It is well established that traditional brushing and flossing, or rinsing with antimicrobials does not penetrate more than a millimeter or two subgingivally. Since most of the active periodontal disease process occurs subgingivally, the necessity of cleaning to the base of the pocket becomes apparent. Fortunately, the Pik Pocket tip attachment for the Waterpik oral irrigator is easy to use and is safe and effective. In a study by Braun and Ciancio, it was discovered that the subgingival tip was able to reach 90 percent of moderate (4-6mm) pockets, and 64 percent of deeper pockets (7mm or above). One final method of irrigation that can be an effective method for delivering an antimicrobial to deeper areas, is the cannula. This method requires commitment, easy access, an isolated area, and high dexterity on the part of the patient.

Some researchers have investigated the efficacy of irrigating with an antimicrobial. Several studies assessed the efficacy of supragingival irrigation with 0.06 percent chlorhexidine (1 part water to 1 part CHX) and demonstrated a significant reduction in gingivitis and bleeding. It is important to mention that water also significantly reduced gingivitis and bleeding and the differences between the groups if statistically significant may be clinically insignificant. A 1990 study used a 3:1 ratio (0.04 percent CHX concentration) with the Pik Pocket tip. Again both the CHX irrigation group and the water irrigation groups show significant reductions in GI along with reduction in the pocket probing depths. Higher concentrations of CHX (0.2 percent) have been studied with positive results but is not available in the United States.

Other irrigants that have been used for home irrigation include stannous fluoride, Listerine® antiseptic, acetylsalicylic acid, hydrogen peroxide, and sodium hypochlorite. Listerine antiseptic is a phenolic compound that has shown antibacterial properties. Listerine antiseptic has only been studied full strength and demonstrated significant reductions in plaque, gingivitis, bleeding, and pathogenic bacteria. Jorgensen and Slots recommend irrigating two to three times a week with a teaspoon of 5.25 percent plain household bleach added to the 300 ml of water. This regimen has never been studied for clinical efficacy or safety.

In-office irrigation

Recently there has been much attention paid to using antimicrobials to combat periodontal disease. Since periodontal disease is a bacterial infection, the practice of using antimicrobials and antibiotics to control the disease makes sense. Many offices have incorporated irrigation to deliver antimicrobials subgingivally, especially after periodontal treatments.

Collectively, studies show that most single applications of antimicrobials have not increased the efficacy of scaling and root planing.

To be of benefit, it is believed that the agent must be applied with enough frequency and duration to keep the bacterial count down. Typically, bacterial counts return to baseline one to eight weeks following a single episode of irrigation. Clearly, the need for additional studies to clarify guidelines and procedures for subgingival irrigation as an adjunct to periodontal therapy are needed but with the introduction of controlled and sustained released delivery systems this area of study may be moot.

Many different agents have been utilized for irrigation for in office application. The most widely studied agent is chlorhexidine. Another irrigant used for in office irrigation, is 10 percent povidone iodine solution (Betadine). The use of povidone-iodine as an antimicrobial has been found to be effective at reducing the number of bacteria in periodontal pockets.

In fact, in an article by Slots, he stated that irrigating with undiluted povidone-iodine might reduce the number of cultivable bacteria by as much as 98 percent. Iodine exhibits rapid antimicrobial action, so is an effective topical agent. Slots also recommends incorporating a 10 percent iodine solution as the irrigant when performing ultrasonic debridement.

Other agents that have been tested for irrigation include, stannous fluoride, saline solution, tetracycline, metronidazole, and hydrogen peroxide. There are many new promising products on the market that deliver a chemotherapeutic agent to the pocket, and maintain effective drug concentrations for at least two weeks. These include Arestin™, which incorporates minocycline into microspheres that can then be injected into the pocket. Another product that may be effective for treating many pockets at a time, is the doxycycline gel, Atridox™. Thus, there are a wide variety of options available to help treat periodontal disease and this is beneficial to the clinician and the patient in their battle against the disease.

Oral irrigation in the dental office can be achieved by several methods. Of course, power scalers provide the easiest and most effective method for irrigating in the office. Using water as the irrigant is helpful to flush out pockets Most of the newer units are available with optional reservoirs that can hold antimicrobials to be used as the irrigant. These provide an easy and efficient way to irrigate with antimicrobials in the dental office. Another type of in-office oral irrigator is a freestanding model by Ora-tec, the Via-jet Professional model. This unit comes with a heated reservoir and the handpiece facilitates delivery of antimicrobial agents subgingivally with a cannula.

Perhaps the biggest advantage of daily irrigation is that it helps patients to maintain a reduced bacterial count in the oral cavity. This in turn leads to fewer bleeding points, more shallow probing depths, and improved gingival health.

The key to success with oral irrigation seems to be consistency, as the bacteria must be continually "knocked down" to achieve maximum benefit. Still, irrigation is only one component of a comprehensive dental care program. Patients must also perform daily thorough toothbrushing, flossing, and any other adjuncts the dental professional deems appropriate. During dental office visits, thorough debridement is still paramount to achieving oral health.

In conclusion, home irrigation can be a key part of treatment planning to care for patients by reducing the numbers of harmful bacteria in the oral cavity, and thus reducing the severity of periodontal disease. Professional irrigation may be limited but new sustained or controlled release devices have shown efficacy when used with scaling and root planing.

Denise Parker, RDH, is a practicing dental hygienist in California. She is a May 2003 graduate from the University of New Mexico.

References available upon request.

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