Contraindications to Dental Whitening

Who shouldn't undergo whitening — from pregnancy to minors under 18 — and why some discolorations don't respond to this type of treatment at all.

Before any whitening treatment, a thorough clinical assessment must rule out a series of specific contraindications. Pregnancy and breastfeeding are among the most cited in the literature: whitening chemical agents can theoretically cross the placental barrier, and although the amount of peroxide systemically absorbed during treatment is generally limited, the lack of conclusive safety data leads most professionals to recommend postponing whitening until after delivery, or at least avoiding it during the first trimester if the patient still chooses to proceed.

Age is another clear-cut contraindication: European regulation (Directive 2011/84/EU) prohibits use of whitening products with concentrations above 0.1% hydrogen peroxide in patients under 18 years old, except in cases where use is intended to treat or prevent a specific pathology. The clinical reason behind this limit isn't purely regulatory: in young patients, enamel is thinner and less mineralized, dentin is closer to the outer surface, and the pulp chamber is significantly larger, with more superficial nerve endings — all factors that significantly increase the risk of hypersensitivity and, potentially, pulp damage.

Other clinical contraindications include: untreated caries or leaking restorations, which should always be resolved before whitening to avoid the chemical agent penetrating unprotected areas; known peroxide allergy; inflamed or unhealthy gums, which should be preventively treated with a professional hygiene session; and the presence of extensive prosthetic restorations in the anterior area (crowns, veneers, large fillings), which don't respond to chemical whitening and can create visible color mismatch against whitened natural teeth.

A limitation often misunderstood by patients concerns the type of discoloration that's treatable: whitening effectively addresses extrinsic discoloration (from external pigments like coffee, tea, wine, smoking) and part of intrinsic discoloration tied to physiological aging, but isn't effective on more severe intrinsic discoloration, such as that caused by tetracyclines taken during tooth development or marked fluorosis. In these cases, even a correctly performed whitening protocol can produce disappointing results, and it's preferable to direct the patient toward alternative solutions like veneers from the outset.

On Oralzon you'll find diagnostic materials for pre-treatment assessment and whitening products at various concentrations, compliant with European regulation, for safe practice that respects clinical contraindications.