Comparative effects of photobiomodulation therapy at wavelengths of 660 and 808 nm on regeneration of inferior alveolar nerve in rats following crush injury

Lasers Med Sci. 2020 Mar;35(2):413-420. doi: 10.1007/s10103-019-02838-w. Epub 2019 Jul 4.


The aim of the present study was to investigate the therapeutic effects of 660-nm and 880-nm photobiomodulation therapy (PBMT) following inferior alveolar nerve (IAN) crush injury. Following the nerve crush injuries of IAN, 36 Wistar rats were randomly divided into three groups as follows: (1) control, (2) 660-nm PBMT, and (3) 808-nm PBMT (GaAlAs laser, 100 J/cm2, 70 mW, 0.028-cm2 beam). PBMT was started immediately after surgery and performed once every 3 days during the postoperative period. At the end of the 30-day treatment period, histopathological and histomorphometric evaluations of tissue sections were made under a light and electron microscope. The ratio of the inner axonal diameter to the total outer axonal diameter (g-ratio) and the number of axons per square micrometer were evaluated. In the 808-nm PBMT group, the number of nerve fibers with suboptimal g-ratio ranges of 0-0.49 (p < 0.001) is significantly lower than expected, which indicates better rate of myelinization in the 808-nm PBMT group. The number of axons per square micrometer was significantly higher in the 808-nm PBMT group when compared with the control (p < 0.001) and 660-nm PBMT group (p = 0.010). The data and the histopathological investigations suggest that the PBMT with the 808-nm wavelength along with its settings was able to enhance IAN regeneration after nerve crush injury.

Keywords: Biostimulation; Inferior alveolar nerve; Nerve injury; Photobiomodulation; Wavelength.

Publication types

  • Comparative Study

MeSH terms

  • Animals
  • Axons / pathology
  • Axons / radiation effects
  • Crush Injuries / radiotherapy*
  • Female
  • Lasers, Semiconductor
  • Light*
  • Low-Level Light Therapy*
  • Mandibular Nerve / pathology
  • Mandibular Nerve / radiation effects*
  • Nerve Crush*
  • Nerve Regeneration / radiation effects*
  • Rats, Wistar