Photobiomodulation for treatment of low back pain in dental professionals

By Dr Alan Kwong Hing, DDS, MSc, Dr Jacqueline Crossman, PhD, MSc, and Dr Michael R Hamblin, PhD

PBM Healing
Fig. 1: A PBM Pain Rehabilitation Belt with the LEDs activated. The red light is visible, but the infrared light is not visible without specialised optical detectors

INTRODUCTION

The International Association for the Study of Pain defines pain as “an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage”. Pain is a distressing sensation caused by inflammation or damaging stimuli.1 It causes the individual to withdraw from potentially dangerous situations to protect a damaged body part while it heals, and to avoid similar experiences in the future.2 Usually, the pain resolves after the noxious stimulus is removed and the body has healed, but it may persist despite the removal of the stimulus and apparent healing. Sometimes pain can arise in the absence of any detectable stimulus, damage, or disease.3

Pain is the most common reason for physician consultation in most developed countries.4,5 It is the major symptom in many medical conditions and can interfere with a person’s quality of life and general functioning.6 According to the Centers for Disease Control and Prevention (CDC), one in five adults in the US experiences chronic pain, which negatively impacts their mental and physical health.7

To manage this pain, most people will consider the use of painkillers, and simple pain medications are useful in up to 70% of cases. However, there are concerns about the long-term use of painkillers, especially if the drugs used by patients are narcotics. Other methods of decreasing pain intensity or discomfort include social support, hypnotic suggestion, cognitive behavioural therapy, electrical nerve stimulation, or distraction.8,9

Low back pain is a common type of acute and/or chronic pain with a high global prevalence. In a systematic review by Hoy et and even chronic pain, including low back pain, should be urgently introduced. al., they reviewed studies published between 1980-2009 on the global prevalence of low back pain. They reported that that the highest prevalence of this type of pain was in females, particularly in those aged 40-80.10 This type of pain was defined as pain or discomfort that is localised above the inferior gluteal folds and below the costal margin. Low back pain may or may not be accompanied by leg pain.

Due to its prevalence, it is one of the most common reasons individuals seek medical care, such as a visit to a physician’s office. It is also the second highest cause of sick leave, and because of the high costs, direct or indirect associated with this condition, it has significant medical, social, and economic effects on individuals, families, and society.11

One common pain management strategy is the use of pharmaceutical drugs, such as painkillers. However, the long-term use of such medications has undesired side effects, and their effectiveness can decrease over time due to increased drug tolerance. Furthermore, stronger painkillers such as opiates for treating chronic pain have been blamed for triggering the current epidemic of overdose induced deaths across the globe. Therefore, alternative approaches for managing acute and even chronic pain, including low back pain, should be urgently introduced.

Photobiomodulation (PBM), also known as low-level laser or light therapy (LLLT), is one suitable alternative approach to pain relief because it stimulates healing, promotes tissue regeneration, and reduces pain and inflammation.12 Application of PBM also results in vasodilation, an increase in the size of smaller arteries and lymph vessels.13 This article describes PBM and its effect on pain and inflammation, as well as providing case reports where the use of PBM delivered by the PBM Pain Rehabilitation Belt (PRB) was successful in resolving low back pain (Fig. 1).

PBM Healing
A PBM Pain Rehabilitation Belt in place on the lower back

PREVIOUS PBM CLINICAL STUDIES

PBM was first used in clinical practice over 40 years ago and its mechanisms of action have been studied for over 30 years.14 It has been widely accepted as a simple, efficient, and cost-effective method of treating both acute and chronic pain.

One preclinical animal study investigated the effect of PBM on pain. The pain threshold was tested in the right hind paw of mice after the application of PBM to various anatomical locations on the body. Their results showed that when PBM was applied to the low back, head, neck, and ipsilateral paw, there was a significant decrease in pain.12 However when PBM was applied to irrelevant sites, contralateral paw, tail, or abdomen, there was no effect.

Other previous studies have demonstrated how PBM could decrease pain in patients with non-specific knee pain,15 temporomandibular disorders,16 fibromyalgia,17 osteoarthritis,18 and neck pain.19 A range of previous trials have also shown the effects of PBM on acute, subacute, and chronic low back pain. Basford et al. and Gur et al. investigated whether PBM was effective in reducing pain and disability triggered by subacute and chronic low back pain.20,21

In a double-blind, placebo-controlled trial, PBM was shown to be easy to use, safe and effective, and it reduced chronic back pain by 50% over six weeks.22 The American College of Physicians’ clinical practice guidelines now recommend PBM as a noninvasive treatment for low back pain.23

Although these study results show the positive effect of PBM on pain, including low back pain, these studies used a variety of wavelengths and combinations of red and infrared light. The choice of red and infrared light used in combination in PBM treatment is due to its differing effects on the tissues.

Red light penetrates the deeper layers of the skin, stimulating cellular repair and increasing circulation. Although infrared light is invisible to the naked eye, it can penetrate more deeply and cause mild thermal effects that increase tissue temperature, promote blood circulation, enhance metabolism, improve cell viability and regenerative capacity, and accelerate healing of scars, wounds, cuts, and nerve damage.24

To read the full article, click here or refer to Dental Asia March/April 2024 issue.

ABOUT THE AUTHORS

Dr Alan Kwong Hing

Dr Alan Kwong Hing DDS, MSc graduated with his Doctor of Dental Surgery degree with distinction from the University of Western Ontario. He received the University Gold Medal and completed a concurrent Master’s Degree in Pathology with a focus on Bone Biology. He has earned multiple degrees and received numerous awards including the IADR predoctoral Hatton award.

Dr Jacqueline Crossman

Dr Jacqueline Crossman, PhD, is the director of research at PBM Healing. She graduated with her Doctor of Philosophy in Medical Sciences, Oral Biology in 2022 from the University of Alberta after completing a Master of Science in Medical Sciences, Oral Biology in 2015 from the same institution.

Dr Michael R Hamblin

Dr Michael R Hamblin, PhD, was a principal investigator at the Wellman Center for Photomedicine at Massachusetts General Hospital, an associate professor of Dermatology at Harvard Medical School for 25 years, and is now a distinguished visiting professor at the University of Johannesburg, South Africa and affiliated faculty at Radiation Biology Research Center, Iran University of Medical Sciences, Tehran, Iran.