Introduction
Hydrogen peroxide has become a popular alternative to commercial mouthwashes in recent years. Some people use hydrogen peroxide as a daily part of their oral hygiene routine. Hydrogen peroxide is an oxidizing agent that can kill bacteria and viruses, making it seem like an ideal mouthwash. However, there are some safety concerns to consider before using hydrogen peroxide as a mouthwash regularly. This article will examine the risks and benefits of using hydrogen peroxide as a mouthwash.
What is Hydrogen Peroxide?
Hydrogen peroxide (H2O2) is a chemical compound made up of two hydrogen atoms and two oxygen atoms. It is a pale blue liquid in its pure form. In nature, hydrogen peroxide is found in rainwater and produced by some animal and plant cells as a natural byproduct.
Commercially available hydrogen peroxide is a diluted solution, usually 3% strength. It has strong oxidizing and bleaching properties. When hydrogen peroxide comes into contact with an enzyme called catalase, it rapidly breaks down into oxygen and water. This reaction produces bubbles, which is why hydrogen peroxide fizzes when applied to cuts and scrapes.
Hydrogen Peroxide as a Disinfectant
Hydrogen peroxide has been used as an antiseptic and disinfectant for over 100 years. In high concentrations, hydrogen peroxide solutions can kill bacteria, viruses, fungi, and spores. According to the U.S. Centers for Disease Control and Prevention (CDC), 3% hydrogen peroxide is a high-level disinfectant effective against TB, HIV, hepatitis B and hepatitis C viruses when used appropriately [1].
Hydrogen peroxide works as a disinfectant through the process of oxidation. The oxygen atoms released from hydrogen peroxide oxidize and damage cell components such as protein, DNA, and lipids in microorganisms. This destroys the cell walls and internal structures of bacteria and viruses.
Using Hydrogen Peroxide as a Mouthwash
Given its strong antimicrobial properties, some people have started using diluted hydrogen peroxide as a daily mouthwash. Generally, a 3% hydrogen peroxide solution is diluted with equal parts water to make a 1.5% mouthwash. About 15-20ml of this solution is swished around in the mouth for 30-60 seconds and then spit out.
Proponents claim hydrogen peroxide mouthwash offers several benefits compared to commercial mouthwashes:
- Kills germs – Hydrogen peroxide is a broad-spectrum antimicrobial that can kill bacteria, viruses, and fungi in the mouth.
- Removes plaque – Some evidence suggests hydrogen peroxide may reduce plaque buildup on teeth.
- Whitens teeth – The bubbling action may help lift stains from teeth and give them a bleached appearance.
- Treats gingivitis – Hydrogen peroxide may reduce inflammation and bleeding associated with gingivitis.
- Improves breath – Killing germs in the mouth could help control bad breath.
- Low cost – Diluted hydrogen peroxide is very inexpensive compared to commercial mouthwashes.
However, there are also some potential risks and downsides to using hydrogen peroxide as a daily mouthwash.
Potential Risks and Dangers
While hydrogen peroxide has disinfectant qualities, frequent use carries some safety concerns:
Cytotoxicity
Several studies have shown hydrogen peroxide mouthwashes are cytotoxic (toxic to cells). When gargled daily, hydrogen peroxide mouthwash can irritate and damage tissues in the mouth, particularly the soft tissues:
- A 1997 study found using a 1.5% hydrogen peroxide rinse twice daily caused noticeable damage to cheek and gum tissues after just 5 days [2].
- Another study from 2003 showed using a hydrogen peroxide mouthwash for 14 days resulted in a greater amount of dead skin cells accumulating on the inner cheeks [3].
- Long-term use of hydrogen peroxide mouthwashes has been associated with various oral lesions, such as leukoplakia (white patches) and Squamous cell carcinoma [4].
Research suggests hydrogen peroxide concentrations above 0.75% are unsafe for daily long-term use. Even diluted solutions have the potential to irritate and damage oral tissues with repeated exposure [5].
Interaction With Tooth Enamel
There are some concerns hydrogen peroxide may damage tooth enamel over time.
A 2007 study found bathing extracted tooth enamel samples in hydrogen peroxide concentrations between 1.5-3% caused enamel surface changes and degradation with extended exposure times [6]. The researchers concluded hydrogen peroxide damaged the organic-rich coating of teeth more than commercial bleaching agents.
However, another study published in 2012 found no significant difference in enamel surface morphology between teeth rinsed with hydrogen peroxide versus saline solution [7]. More research may be needed to determine hydrogen peroxide’s effects on enamel with repeated use.
Tooth Sensitivity
Hydrogen peroxide mouthwashes often cause temporary tooth sensitivity and irritation. In a 2003 study, over 60% of participants using a hydrogen peroxide rinse experienced some tooth sensitivity, compared to just 25% using a normal saline solution [3].
Tooth sensitivity may be worse for people with exposed root surfaces from receding gums. The high oxidation potential of hydrogen peroxide could penetrate deep into dentinal tubules and irritate the tooth nerve.
Tissue Damage and Cancer Risk
There is some concern hydrogen peroxide use could increase the risk of oral cancer. A 2009 review published in the International Journal of Dentistry concluded:
“Evidence suggests that long-term exposure to H2O2 increases the risk of oral cancer. Therefore dental practitioners should avoid prescribing it as an oral health product” [4].
This is linked to the potential for hydrogen peroxide to cause irritation, inflammation, and damage to oral tissues. However, more rigorous clinical studies in humans may be needed to determine cancer risk.
Safety for Children
Hydrogen peroxide mouthwashes should never be used by children, even diluted. Children are at higher risk of accidentally swallowing hydrogen peroxide, which can cause abdomen pain, vomiting, and life-threatening gas embolisms [8].
The FDA advises parents never use or store hydrogen peroxide solutions around children without tight supervision [9].
Interference With Dental Work
Hydrogen peroxide may react negatively with dental materials. Using hydrogen peroxide around dental appliances like dentures, crowns, fillings, and implants could damage them or leach chemicals out of the materials [10]. Hydrogen peroxide is also known to reduce bond strength of dental adhesives used in certain procedures [11].
Professional Opinion on Hydrogen Peroxide Mouthwash
Given the potential risks, using hydrogen peroxide as an everyday oral rinse is not recommended by most dental organizations.
The American Dental Association (ADA) advises against using hydrogen peroxide for anything other than short-term disinfection of toothbrushes or dental appliances. They do not endorse hydrogen peroxide for daily oral hygiene [12].
Similarly, the Canadian Dental Association states hydrogen peroxide has an “unacceptable toxic effect on oral tissues with extended use” and should be avoided as a regular mouthwash [13].
Most dental professionals recommend sticking to mouthwashes formulated specifically for daily oral care needs. Common active ingredients in commercial mouthwashes include cetylpyridinium chloride, essential oils, chlorhexidine gluconate, and fluoride. These have a better safety profile than hydrogen peroxide with repeated use.
Benefits Analysis
While hydrogen peroxide exhibits antimicrobial properties in lab studies, there is little clinical evidence it offers significant benefits over conventional mouthwashes for daily use.
Killing Germs
Research shows hydrogen peroxide only has a bactericidal effect in the mouth for about 30 minutes after rinsing before levels return to normal [14]. In comparison, cetylpyridinium chloride mouthwashes show antimicrobial activity for 3-12 hours against plaque bacteria [15].
Essential oil mouthwashes can also suppress oral bacteria for prolonged periods after use [16]. So commercial formulations seem more effective than hydrogen peroxide for ongoing germ-killing between brushing.
Whitening Teeth
There are few studies assessing hydrogen peroxide mouthwashes for teeth whitening compared to professional or over-the-counter whitening treatments. Any perceived whitening effect from hydrogen peroxide mouthwash is temporary and superficial, not permanent deep whitening of enamel.
A review in the Journal of the American Dental Association concluded hydrogen peroxide concentrations below 6% have very limited tooth whitening ability [17].
Improving Breath
Bad breath is primarily caused by bacteria on the tongue, not necessarily in other oral tissues. While hydrogen peroxide can reduce bacteria in saliva, there is little evidence it has a lasting deodorizing effect. Mouthwashes formulated specifically for bad breath often contain active ingredients like zinc, chlorhexidine, or cetylpyridinium chloride proven to neutralize odors over time [18].
Based on the current evidence, hydrogen peroxide mouthwash seems less effective than commercial options designed to treat bad breath. More clinical studies could help determine effects on halitosis.
Treating Gingivitis
In a small-scale study of 15 participants, using a 1.5% hydrogen peroxide rinse improved gingivitis severity after a 3-week period compared to a placebo rinse [19].
However, larger-scale studies have found chlorhexidine and essential oil mouthwashes more consistently effective for reducing gingivitis than hydrogen peroxide [20][21].
The evidence does not support hydrogen peroxide as a preferred treatment for gum inflammation over proven anti-gingivitis mouthwashes.
Alternative Uses
While not ideal as a daily mouthwash, hydrogen peroxide does have some appropriate oral care uses when utilized carefully.
The ADA acknowledges hydrogen peroxide has temporary efficacy for disinfecting toothbrushes and dental appliances like retainers, dentures, and mouthguards [12].
Many dentists recommend using a 3% hydrogen peroxide solution in a 50/50 dilution with water to soak oral appliances for about 10 minutes. This can help kill bacteria and prevent transferring germs into the mouth.
Hydrogen peroxide mouthwashes or pastes can also be prescribed by dentists at stronger concentrations to treat certain periodontal conditions. In-office application under supervision allows using hydrogen peroxide therapeutically while limiting side effects.
There may also be a role for hydrogen peroxide washes before dental procedures to reduce oral microbes. One study found pre-treatment with a 1.5% hydrogen peroxide rinse significantly decreased bacterial aerosolization during ultrasonic scaling [22].
Further research on professional applications of hydrogen peroxide is warranted.
Conclusion
Hydrogen peroxide has the potential to damage oral tissues and cause sensitivity when used as a daily mouthwash. Commercial mouthwashes with better safety profiles seem preferable for maintaining oral hygiene. Hydrogen peroxide mouthwash is not recommended for children due to toxicity risks if swallowed.
Diluted hydrogen peroxide may still have a place as a short-term disinfectant for oral appliances and toothbrushes. It could also be beneficial when professionally applied as part of certain dental treatments. Patients should consult their dentist before using any non-traditional oral rinse regularly.
More well-designed clinical studies are needed to investigate the risks and benefits of hydrogen peroxide mouthwash compared to conventional options. But based on current evidence, hydrogen peroxide has more drawbacks than advantages for routine use as an antimicrobial mouthwash.
References
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