Allende J.B. et al. - Photobiomodulation and Tooth Sensitivity After Whitening: An Umbrella Review

This umbrella review of 10 systematic reviews concludes that laser or light activation does not improve the results of in-office teeth whitening and does not reduce sensitivity. Conversely, photobiomodulation reduced post-whitening sensitivity in randomized placebo-controlled trials without compromising the shade change.

What this study measured

Allende’s team at the University of Chile’s School of Dentistry searched PubMed, Embase, Scopus, Web of Science, and the Cochrane Library for systematic reviews and meta-analyses on in-office teeth whitening using optical activation or photobiomodulation. This is therefore a synthesis of syntheses, representing the highest level of evidence in the hierarchy of reviews.

Three distinct questions were examined: Does activation by laser or light improve the effectiveness of teeth whitening? Does it affect tooth sensitivity? What are the biological safety data, particularly regarding the pulp? The methodological quality of the reviews was assessed using the AMSTAR 2 tool, and the certainty of the evidence was evaluated according to a framework specific to umbrella reviews.

Key Findings

The findings clearly distinguish between two uses of light that are often confused.

• 10 systematic reviews were included, published between 2007 and 2024.
• Laser or light activation: no consistent improvement in the final whitening efficacy compared to protocols without activation.
• Tooth sensitivity: not reduced by activation, and less favorable in certain high-energy protocols.
• Photobiomodulation: reduction in post-bleaching sensitivity in randomized, placebo-controlled trials, without affecting the color change.
• Safety: Results depend primarily on the parameters, particularly the intrapulpal temperature during high-energy activation.

How photobiomodulation works for this indication

Optical activation aims to accelerate the chemical reaction of hydrogen peroxide by applying heat or light energy. Photobiomodulation has a different objective: when applied at low intensity, it seeks to modulate the pulp inflammatory response and nerve transmission that cause the sensitivity following teeth whitening.

The review supports this distinction. High-energy protocols pose a thermal challenge for the pulp, whereas photobiomodulation—which does not generate heat—is associated with less sensitivity in the selected studies. The authors do not report a quantified average effect in the abstract.

Limits You Should Know

An umbrella review inherits the weaknesses of the studies it aggregates: potential overlap of primary trials across studies, and heterogeneity in bleaching protocols, light sources, and sensitivity scales. The abstract does not specify either the number of primary trials or the number of patients involved in the photobiomodulation arm.

Two negative findings should be noted as they stand: activation by laser or light does not improve the final shade, nor does it reduce sensitivity. These conclusions do not apply to photobiomodulation, whose reported effect pertains solely to sensitivity.

What This Means in Practice

For dental practices, this review advises against justifying the use of an activation lamp or laser on the basis of increased whiteness—a claim not supported by the data—and recommends monitoring the thermal parameters of high-energy protocols.

Photobiomodulation, on the other hand, appears to be a viable adjunct for reducing sensitivity in patients who are prone to it, without compromising the aesthetic result. The decision ultimately rests with the dentist, depending on the whitening protocol used and the condition of the tooth.

Frequently Asked Questions

Do the light or the laser make teeth whitening more effective?

According to this umbrella review of 10 systematic reviews, no: laser or light activation has not shown a consistent improvement in final whiteness compared to protocols without activation.

Does photobiomodulation reduce sensitivity after teeth whitening?

The randomized, placebo-controlled trials included in the review report reduced post-bleaching sensitivity with photobiomodulation, without any loss of efficacy in terms of shade. The magnitude of the effect is not quantified in the abstract.

Is light-activated teeth whitening dangerous for the pulp?

The review highlights parameter-dependent thermal concerns, particularly for high-energy activations that raise the intrapulpal temperature. This issue does not apply to low-intensity photobiomodulation.

Reference

Allende JB, Campos-Bijit V, Morales-Gómez C, Díaz L, Gómez VC, Fernández E. Do Laser and Light Activation Improve In-Office Dental Bleaching Outcomes? An Umbrella Review of Efficacy, Tooth Sensitivity, and Biological Safety. J Esthet Restor Dent, 2026, 38(9), 1665-1690. PMID 42076873. View the record on PubMed

This summary is provided for informational purposes only and does not constitute medical advice. Photobiomodulation is not a substitute for prescribed treatment. Consult a healthcare professional.