Teeth whitening, or bleaching, is a common cosmetic procedure used to lighten the color of teeth using peroxide-based agents. These agents, typically hydrogen peroxide or carbamide peroxide, penetrate the enamel to break down stain compounds. While the focus of this treatment is on the tooth structure, a frequent concern for individuals considering whitening is the effect these powerful chemicals may have on the soft tissue of the gums. This article will address the question of whether teeth whitening is harmful to gums and detail the steps that can be taken to minimize any potential risk.
The Mechanism of Gum Irritation
The primary danger to the gums during a whitening procedure is chemical irritation caused by direct contact with the bleaching gel. This irritation occurs because peroxide, the active ingredient, acts as a strong oxidizing agent that can damage soft tissues. The severity of the reaction is proportional to both the concentration of the whitening agent and the total duration of exposure. In-office treatments may use hydrogen peroxide concentrations up to 35%, while at-home kits typically contain lower amounts, sometimes up to 14%.
When the gel touches the gum tissue, it can cause temporary, localized inflammation known as gingival blanching, where the gums turn white. This reaction is transient and reversible, with the tissue returning to its normal color within a few hours to a day once contact is removed. Prolonged exposure to highly concentrated peroxide can cause more significant pain and damage.
The oxidizing molecules can penetrate the tissue, leading to a stinging or burning sensation. While gums possess a natural ability to heal from minor chemical exposure, improper application can overwhelm this defense. If the gel is allowed to consistently pool on the gums, the resulting irritation may lead to inflammation or a delay in the healing process.
Preventing Chemical Contact
The method of protection depends on the application technique, but protecting the gums is a necessary step in any safe teeth whitening regimen.
Professional In-Office Whitening
During professional in-office whitening, the dentist applies a light-cured resin dam, known as a gingival barrier, directly onto the gums. This resin forms an impermeable, physical shield that prevents the high-concentration bleaching agent from reaching the soft tissue. This meticulous application ensures the whitening material remains solely on the tooth surface.
Custom At-Home Trays
For at-home tray systems provided by a dental professional, safety relies on the precise fit of the custom-made appliance. These trays are fabricated from an impression of the patient’s mouth. The snug fit keeps the whitening gel contained to the tooth surface, preventing it from leaking out and causing irritation to the gingival margins.
Over-the-Counter Kits
Over-the-counter kits often use generic, one-size-fits-all trays or whitening strips, which rarely fit accurately. When using these non-customized products, apply only a minimal amount of gel or place the strips exactly on the teeth without pushing them onto the gum tissue. Any excess gel or strip covering the gum line should be immediately wiped away to minimize exposure and reduce the risk of irritation.
Pre-Existing Conditions and Risk
The risk profile for gum irritation changes significantly when a person has pre-existing oral health issues. Individuals with active gum disease, such as gingivitis or periodontitis, should generally avoid teeth whitening until the condition is treated and controlled. The bleaching agents can exacerbate the existing redness and inflammation associated with gum disease, causing increased pain and hypersensitivity.
Gum recession, which exposes the root surface of the tooth, is another condition that requires professional assessment before whitening. The exposed root lacks a protective enamel layer and is covered by the softer dentin. Applying whitening gel to these areas can cause severe sensitivity and may lead to non-uniform whitening results.
Any open sores, cuts, or abrasions on the gums can be intensely aggravated by the peroxide, potentially delaying the healing process. For these reasons, undergoing a thorough dental checkup before beginning any whitening treatment is necessary. A dental professional can confirm that the gums are healthy enough to tolerate the procedure and can recommend the safest method.