Light distribution of 635 nm LED for PBM treatments in the maxillofacial region

Introduction: Photobiomodulation (PBM) therapy is an application of light for the therapeutic purpose of improving tissue regeneration, reducing inflammation, or inducing analgesia. While several questions regarding the PBM effects are well documented, questions on penetration and distribution of light through the hard and soft tissues of the maxillofacial region, in vivo, have not been well investigated. The aim of this in vivo study was to assess pulsed 635 nm extraoral PBM light distribution through the cheek and upper and lower jaws, with and without teeth. Material and methods: In 23 patients, an extraoral LED device emitting pulsing light (wavelength: 635 nm, maximum output power: 140 mW/cm, frequency: 2,5 Hz, duty cycle: 50%) was used to illuminate the cheek, upper and lower jaws. A power meter sensor registering the optical power was placed intraorally to assess light penetration through tissues. Results: Light penetration was present in all patients, in both soft and hard tissues. Light distribution through the cheek was 148,6 μW while in the upper jaw it was 6,1 μW and in the lower jaw 5,4 μW. There was a significant difference in light distribution between soft tissues (cheek) and hard tissues (upper and lower jaw). There was no significant difference between patients with teeth and without teeth. Conclusion: This study demonstrated an existent penetration of extraoral PBM 635 nm light through the soft and hard tissues in the MF region. The significant difference in light attenuation between the soft and hard tissues indicates a need for reassessment of dosage in treating different tissues in patients, in order to obtain an adequate amount of energy delivered and thus an optimal therapeutic outcome.