Creazzo G. et al. - Photobiomodulation as an Adjunct to Endodontic Treatment of Periapical Lesions: A Systematic Review and Meta-Analysis

In 6 studies evaluating the use of laser therapy in addition to endodontic treatment of periapical lesions, the meta-analysis found no difference in radiographic healing compared with conventional treatment alone (mean difference 0.17; 95% CI -0.14 to 0.47; p = 0.28). The certainty of the evidence is rated as low.

What this study measured

A periapical lesion is an area of bone destruction at the tip of a tooth root resulting from an infection in the root canal. Conventional endodontic treatment, which involves cleaning and filling the root canal system, generally allows the bone to regenerate. The question addressed here is whether the use of a laser improves this outcome.

The authors included 6 studies, both randomized and non-randomized. The primary outcome measure was the Periapical Index, a standardized radiographic score that assesses the extent of the lesion. The effects under investigation combined a photobiomodulatory effect on healing with an antimicrobial effect within the root canal. The certainty of the results was assessed using the GRADE method.

Key Findings

The result is inconclusive: no superiority of the adjunctive laser treatment was demonstrated.

• Mean difference in the Periapical Index: 0.17 (95% CI: -0.14 to 0.47)
• Significance threshold not met: p = 0.28
• Heterogeneity across studies: I² = 52%, classified as moderate
• Number of studies included: 6
• GRADE certainty: low

The confidence interval encompasses the value zero, which means that the data are consistent with both a slight benefit and a slight disadvantage of the adjuvant laser.

How photobiomodulation works for this indication

Two mechanisms were expected. The first is antimicrobial: light, either alone or in combination with a photosensitizer, is thought to target residual bacteria in the dentinal tubules that mechanical instrumentation cannot reach. The second is photobiomodulatory in the strict sense: it supports the activity of periapical bone cells to accelerate reconstruction.

None of these effects result in a measurable radiographic improvement in this study. One plausible explanation—which the authors did not test—is that conventional endodontic treatment is already highly effective for this indication, leaving little room for an additional intervention to demonstrate a benefit.

Limits You Should Know

Only six studies could be included, and their methodological quality is limited. The authors note that all randomized trials have methodological limitations and that the sole non-randomized study is at a high risk of bias. The GRADE certainty is low.

As with any negative result based on a small number of studies, the absence of a significant difference does not prove the absence of an effect. A moderate benefit might be overlooked in an analysis of this size. Finally, the 52% heterogeneity and the diversity of devices grouped under the term “laser” complicate the interpretation.

What This Means in Practice

Based on the current evidence, there is no justification for using adjunctive laser therapy for the sole purpose of accelerating the healing of a periapical lesion. Properly performed endodontic treatment remains the primary determinant of the outcome.

This finding says nothing about other indications for photobiomodulation in dentistry, where more favorable data exist—particularly regarding pain. Above all, it illustrates that the benefit cannot be generalized from one indication to another. The decision rests with the dentist.

Frequently Asked Questions

Does laser treatment improve the outcome of a root canal?

This meta-analysis did not examine the radiographic healing of periapical lesions. The mean difference on the Periapical Index was 0.17, with p = 0.28, which is not statistically significant.

Is this negative result reliable?

It is based on 6 studies of limited methodological quality and a low GRADE certainty. It should therefore be interpreted as a lack of evidence of benefit, rather than as evidence of a lack of benefit.

Is photobiomodulation useless in dentistry?

No, this study focuses on a specific indication. Other reviews report favorable results regarding postoperative pain or oral mucositis, but this does not necessarily imply favorable periapical bone healing.

Reference

Creazzo G, Salmon B, Almeida J, Faria-E-Silva AL, Lopes-Olhê FC, Souza-Gabriel AE, Sousa-Neto MD, Candemil AP. Does the use of laser therapy enhance healing and reduce the size of periapical lesions? A systematic review and meta-analysis. Photodiagnosis and Photodynamic Therapy, 2026. PMID 42001923. PubMed link

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.