Dental Asia March/April 2024

CLINICAL FEATURE
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
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
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 overdoseinduced
deaths across the globe. Therefore,
alternative approaches for managing acute
Fig. 1: PBM PRB with the LEDs activated. The red
light is visible, but the infrared light is not visible
without specialised optical detectors
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).
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,
30 DENTAL ASIA MARCH / APRIL 2024