The oral irrigator is scientifically proven to reduce several clinical parameters, including biofilm, dental plaque, calculus, bleeding, gingivitis, periodontal pathogens, probing depth and inflammatory mediators. 

INTRODUCTION 

The oral irrigator was invented by dentist Dr. Gerald Moyer and engineer, John Mattingly in the late 1950s in the United States, and was introduced to dental professionals at a convention in Texas in 1962. It is a device that releases a pulsating stream of water, either alone or combined with an antiseptic, which causes a compression and decompression phase that is ideal for removing food debris and biofilm and for massaging gums without damaging them. 

The pressure is crucial for these devices, which must be between 50 and 90 psi to be effective⁽¹⁾. These devices provide a pulsation rate of approximately 1200 per minute, which creates two zones of hydrokinetic activity: the supragingival zone, where the stream first hits, and the flushing zone which is the subgingival area where the solution penetrates for irrigation. 

Because they are convenient, oral irrigators boast good patient compliance and are easily used as part of a normal daily oral hygiene routine. The irrigator tip should be aimed toward the tooth surface, and left for a few seconds on each surface. This process be repeated for all teeth, and the same route should always be followed, making sure not to miss any teeth. Different types of solutions can be used, but the most recommended is water alone, as it is the most economical and widely available, does not cause side effects and is backed by scientific studies. 

Another solution that has been studied is water combined with chlorhexidine. Some studies have found better interproximal and subgingival penetration with the use of mouthrinses compared to the use of water alone⁽²⁾. 

The efficacy and safety of irrigators have been shown in multiple studies which have evaluated soft tissues after use with an oral irrigator, verifying that no damage was produced, and positive effects on the keratinized gingiva and on the capillary vascularisation were observed⁽³⁾. 

REDUCTION OF CLINICAL PARAMETERS 

The oral irrigator has been scientifically proven to reduce several clinical parameters, including biofilm, dental plaque, calculus, bleeding, gingivitis, periodontal pathogens, probing depth and inflammatory mediators. 

Mechanical biofilm removal is one of the most effective methods for its control. The flushing effect of the irrigator can cause quantitative and qualitative changes in biofilm or dental plaque by diluting and detaching it. In an in vitro and in vivo study on biofilms, a near 99.9% reduction of this biofilm was observed through scanning electron microscopy after 3-second application on the surface being treated⁽⁴⁾. 

In another patient study, the use of toothbrushing plus irrigation was compared to toothbrushing plus dental flossing, and greater plaque reduction was observed in the patients who used irrigation⁽⁵⁾. Furthermore, and thanks to the special replacement tips available, access to subgingival biofilm is greater even when patients have periodontal pockets. Similarly, calculus reduction is significant with the use of these devices. 

Oral irrigators have also proven to significantly reduce gingivitis and bleeding on probing. A 4-week study conducted by the University of Nebraska (United States) on 105 subjects showed how the use of an oral irrigator together with manual or electric toothbrushing improved bleeding and gingivitis indices – practically twice as effective – compared to brushing and flossing⁽⁶⁾. 

Likewise, another recent study showed that the combination of manual brushing and oral irrigation is twice as effective at reducing bleeding on probing compared to brushing and flossing⁽⁷⁾. 

With regard to inflammation, the oral irrigator has shown not only to reduce biofilm, but also to change the structure of the biofilm making it less pathogenic for the host⁽⁸⁾. This was also observed in another study, which revealed a significant reduction in cytokines and proinflammatory mediators including IL-1ß and PGE2⁽⁹⁾, which would explain this mechanism and would support the use of irrigators by people who have difficulty controlling biofilm. 

Irrigators have also proven to reduce levels of subgingival pathogenic bacteria by 6 millimetres, regardless of the solution used, an effect that can be enhanced by the use of special replacement tips for application to difficult-to-reach areas. 

PEOPLE WITH SPECIAL NEEDS 

Oral irrigators have been studied in different special clinical situations. One study found that when used with periodontal tips, the oral irrigator improved parameters relating to biofilm, bleeding and gingivitis in patients with diabetes, besides reducing the expression of destructive inflammation mediators IL-1ß and PGE2⁽¹⁰⁾. 

Another recent study has proven the safety and efficacy of the oral irrigator together with a special replacement tip in patients with implants. Brushing plus irrigation was compared to brushing plus flossing, and very significant differences were observed in relation to bleeding reduction in favour of the patients who used irrigators⁽¹¹⁾. 

The oral irrigator has also proven to be greatly useful in periodontitis patients who are undergoing periodontal maintenance therapy and as a supplement to routine oral hygiene measures, by reducing gingival inflammation, bleeding on probing and probing depth⁽¹²⁾. 

Lastly, a significant improvement in bleeding and inflammation indices has also been seen in orthodontic patients who used an oral irrigator compared to those who used brushing alone, and even a significant improvement compared to brushing along with flossing⁽¹³⁾. The different studies mentioned in this article are based on studies conducted with Waterpik^® oral irrigators.