Photobiomodulation for the Management of Temporomandibular Disorder Pain
Phase: NA
Conditions: Pain Related to TMD
Sponsor: University of Florida

PHOTOBIOMODULATION FOR THE MANAGEMENT OF TEMPOROMANDIBULAR DISORDER PAIN  
NCT: 04415281  
5/13/2021 

Protocol 
1. Project Title: 
PHOTOBIOMODULATION FOR THE MANAGEMENT OF TEMPOROMANDIBULAR DISORDER PAIN 
2. Investigator(s): Dr. Margarete Ribeiro-Dasilva, DDS, MS, Ph.D (Contact PI)  
       Dr. Roger B. Fillingim, PhD (PI) 
3. Abstract: 
Given the paucity of effective treatments for TMD and the overuse of pain medication, well-designed 
studies are needed to evaluate pharmacological alternative to treat this chronic pain condition. Our goal 
in this study is to conduct a double blinded, sham controlled, randomized clinical trial of multimodal 
Photobiomodulation (PBM) for TMD pain. Also, we propose to determine if PBM-induced changes in 
inflammation and pain sensitivity contribute to PBM’s analgesic effects. A total of 120 TMD participants 
will be recruited through community-based advertisements. Participants will complete a computer-
assisted telephone screening (CATI). Eligible participants will be age 18 and older with pain intensity of 
≥30 on a visual analog scale (0-100). Participants will be excluded if: a) starting a new daily prescription 
medication for the management of pain within 30 days before TS; b) use of injection therapy (e.g., 
tender or trigger point injections, steroid injections) for the management of pain within 2 weeks before 
the CATI; c) starting occlusal appliance therapy within 30 days before CATI; d) history of facial trauma 
or orofacial surgery within 6 weeks before CATI; e) active orthodontic treatment; f), psychiatric 
hospitalization within one year before the screening. Participants eligible after CATI will be scheduled 
for a pre-randomization visit (V0), six treatment visits (V1 to V6). V0 will include informed consent, 
completion of a detailed medical history and the Pain, Enjoyment, General Activity (PEG) Scale, 
followed by a clinical exam to confirm TMD status according to the Diagnostic Criteria for TMD 
(DC/TMD), Pressure Pain Sensitivity (PPT) and blood draw. V1 will be the randomization visit to either 
receive PBM or Placebo, during which the first treatment will be delivered. There will be 5 subsequent 
treatment visits. At the final visit, a blood draw, a standard movement task to evaluate the range of 
motion of the mouth and PPT will be performed. PBM/Placebo treatment: We will use three types of 
active/Placebo probes; A) Single Laser 810 NM 200 mw; B) Laser Cluster of 810 NM equivalent to 1 
WATT and; C) LED Cluster, 34 X 660nm at 10 mw and 35 850nm, 30mw 1390mw total applied to 
multiple craniofacial sites. Analyses will determine treatment effects on the primary outcome (pain 
intensity) and multiple secondary outcomes, and will examine whether changes in inflammation and 
pain sensitivity mediate treatment response. Findings from this rigorously designed trial will provide the 
most definitive evidence to date regarding the effectiveness and mechanisms of PBM for treating TMD 
pain. 
4. Background 
According to the National Institute of Dental and Craniofacial Research (NIDCR), in the United States, 
up to thirty-nine million Americans suffer from Temporomandibular joint and muscle disorder (TMD). 
Among them, more than ten million Americans suffer from chronic TMD pain (1) . In 2001, TMD resulted 
in 17.8 million lost working days yearly for every 100 million working adults in the United States and that 
financial costs are in the billions of dollars (2). TMD is, therefore, the 4th most common pain condition in 
the US population; it is a complex musculoskeletal disorder characterized by muscle and joint pain and 
limited jaw function.  TMD treatment is of limited efficacy. Evidence-based treatments for TMD are 
lacking, and the most common treatments for TMD, intraoral appliances and pain medication, including 
opioids, provide suboptimal pain control and can produce treatment-limiting side effects(3-5) . Therefore, 
as recently highlighted in a consensus report from the National Academies of Sciences Engineering 

and Medicine, (6) the development of new safe and effective therapy is crucial to improve the quality of 
life of patients suffering from this painful condition.   
Recent years have witnessed a burgeoning interest in the therapeutic potential of Low-Level Laser 
Therapy (LLLT) and Light-emitting Diodes (LED), recently named Photobiomodulation (PBM), in pain 
and inflammation. LLLT and LED therapies are both designed to deliver energy to target tissues to 
impact biological processes through photobiomodulation. Briefly laser and LED light stimulates 
photoreceptors in the target tissue(s), activating secondary mediators and thereby influencing multiple 
biological processes, including gene expression, cell signaling, cellular metabolism and cytokine 
release(7) . Therapeutic LLLT and LEDs are often manufactured to emit similar wavelengths in the red or 
near-infrared spectrum; however, these two modalities differ in important ways. First, laser light is both 
columnated and coherent (i.e. organized), which allows lasers to deliver light to a narrowly focused 
area of tissue and with deeper tissue penetration. Also, laser light is delivered at a single wavelength, 
allowing it to target biological processes that respond only to specific wavelengths (e.g. mitochondria) (8-
10) . In contrast, LEDs emit light beams that are neither coherent nor columnated and are of lower power 
than lasers, and these properties limit LED penetration to more superficial tissues. Notably, multiple 
LEDs can be arranged into arrays, which increases the area of tissue that can be stimulated. (7) Thus, 
while these two forms of PBM share similarities, there are important differences that render them 
potentially highly complementary in the treatment of musculoskeletal pain.  
PBM therapy has been demonstrated to have several benefits to muscles. It can prevent muscle 
damage after exercise, including delayed onset muscle soreness; and increase capacity of muscle 
workload, improving fatigue resistance, functional and activity and fastening muscle recovery. These 
benefits to muscle function could potentially improve TMD pain, which commonly originates in muscle. 
Another mechanism implicated in TMD pain is inflammation. Indeed, increased circulating levels of pro-
inflammatory cytokines, such as interleukin-1β (IL-1β), IL-6, tumor necrosis factor-alpha (TNF-α), and 
monocyte chemoattractant protein-1 (MCP-1) has been observed in patients with TMD for both myalgia 
and arthralgia. This systemic inflammation can influence the response properties of nociceptive 
afferents, resulting in peripheral sensitization (11) which can increase the intensity of TMD pain. (12) Over 
time, this increased nociceptive activity can produce changes in the response properties of spinal and 
trigeminal brainstem neurons, leading to central sensitization that can produce more widespread 
hyperalgesia and allodynia. Interestingly, PBM therapy has been shown to decrease the release of 
several cytokines (e.g.; IL6, TNF-α, MCP-1, etc.)(13-17), which could, in turn, reduce TMD pain. 
Finally, TMD has been associated with peripheral and central sensitization, partially mediated by 
glutamate, N-methyl-D-aspartate (NMDA)(18, 19)  as well as with increased oxidative stress(20, 21) 
.Interestingly, following injuries to the nervous system (both peripheral and central), PBM has been 
shown to promote axonal growth and nerve regeneration, as well as a change in the redox state of the 
cell, reducing oxidative stress and consequently reducing excitotoxicity. Because excitotoxicity involves 
the abundant release of the excitatory neurotransmitter glutamate, this could continue the cycle of 
glutamatergically-mediated central sensitization. Therefore, PBM can reduce TMD pain by reducing 
oxidative stress and subsequent excitotoxicity. 
Moreover, existing evidence suggests that PBM therapy may reduce pain associated with multiple 
chronic pain conditions that share some common features to TMD pain, such as whiplash injury(22),  
tendinitis (23), osteoarthritis(24, 25), rheumatoid arthritis,  neck, and back pain(26), epicondylitis (27), 
fibromyalgia (28), post-herpetic neuralgia (29), and trigeminal neuralgia (30, 31).  While these studies support 
the potential benefits of PBM in treating chronic pain, these studies have not combined PBM modalities, 
nor have they implemented the credible placebo condition proposed in this trial. 
Given the multiple contributing mechanisms (e.g., muscle dysfunction, peripheral & systemic 
inflammation, peripheral and central sensitization), we hypothesize that treatments targeting multiple 

pathophysiological pathways may be more effective in treating TMD. Therefore, we propose to 
rigorously test a promising non-pharmacologic approach to treat chronic TMD pain via PBM with both 
LLLT and LED, targeting several potential pathophysiological pathways for TMD pain. We hypothesize 
that the proposed protocol has the potential to improve symptoms and reduce reliance on pain 
medication in the future.  
5. Hypotheses and Specific Aims: 
SA1: To investigate the analgesic efficacy of multi-wavelength PBM protocol [810nm 
200mw; 810nm 1W aggregate and 660nm (10mwx34) aggregate 850nm (30mw x 35) LED] versus 
placebo PBM in patients with chronic TMD. Therefore, we will test the following hypothesis: H1a: 
compared to a credible placebo condition, the proposed PBM protocol will significantly reduce TMD 
pain.  
SA2: To investigate whether multimodal PBM changes inflammatory responses and mechanical 
pain sensitivity in patients with TMD and to determine the association of these changes with the 
analgesic response. The majority of studies investigating the biological effects of PBM therapy have 
been conducted in preclinical models using a single wavelength in an injured site, and these findings 
suggest that PBM can reduce the inflammatory response. Our goal is to evaluate, in humans, the effect 
of the multi-wavelength PBM protocol on the inflammatory response and on mechanical pain sensitivity 
among individuals with TMD. Therefore, we will test the following hypothesis: H2a: the PBM protocol 
used will reduce the amount of circulating pro-inflammatory cytokines and will increase mechanical pain 
thresholds. H2b PBM-induced changes in inflammation and pain sensitivity will be associated with the 
magnitude of reductions in clinical pain following PBM.  
6. Research Plan: 
This study proposes to validate the use of an existing device that does not have FDA approval for use 
in treating chronic pain related to TMD. However, this device is already FDA approved for relaxation of 
muscles and relief from muscle spasms, temporary relief of minor muscle and joint aches, pain and 
stiffness, temporary relief of minor pain and stiffness associated with arthritis, temporarily increase 
blood circulation. Because we are studying individuals with muscle and joint pain due to TMD, the 
condition we are studying falls within the scope of conditions for which the device is FDA approved. 
(R#3006747388,https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfRL/rl.cfm?start_search=&Owner
OperatorNumber=9054807).  
6.1 Overall Study Design: This study will be a double-blind, sham-controlled, randomized trial testing 
the efficacy of photobiomodulation (PBM) for pain related to TMD. Figure 1 depicts the study flow chart 
and each activity for each visit. After initial eligibility screening, potential participants will complete a 
clinical visit (V0) to confirm eligibility and verify their TMD status via clinical examination using the 
Diagnostic Criteria for Temporomandibular Disorder (RDC/TMD). Enrolled patients will complete an 
electronic daily symptom diary (DSD) for one week prior to the randomization visit (V1). V1 will include 
assessment of pain during movement and Pressure Pain Threshold, and a blood draw for 
measurement of inflammatory markers. Participants will then be randomized to either active or sham 
PBM, with the first treatment applied at V1. This will be followed by five more clinical visits, such that all 
participants will complete two to three treatment visits per week for two to four weeks. PPT, jaw range 
of motion and a blood draw will be repeated at the final visit. Likewise, Daily Symptom Diaries will be 
completed for one week midway through treatment and leading up to the final visit.  
6.2 Participants: A total of 120 participants with chronic TMD, age 18 years and older will be enrolled 
at the University of Florida, College of Dentistry. As in our prior studies, recruitment will be community-
based, including advertising across multiple prints and electronic media (e.g., posted flyers, radio, 
newspaper, social media, etc.). These methods have been highly effective in our prior studies. All 
participants that contact us will complete the pre-screening computer assisted telephone interview 

(CATI). Participants eligible to attend an enrollment visit 
will be those with facial pain for at least 3 months and 
an average pain intensity rating for the week preceding 
CATI, of ≥30 on a visual analog scale VAS (0-100).  
6.3 Exclusion Criteria: Participants will be excluded if: 
a) starting a new daily prescription medication for the 
management of pain within 30 days prior to treatment 
session; b) use of any injection therapy (e.g., tender or 
trigger point injections, steroid injections) for the 
management of pain within 2 weeks prior to the CATI; 
c) starting occlusal appliance therapy within 30 days 
prior to CATI; d) history of facial trauma or orofacial 
surgery within 6 weeks prior to CATI; e) active 
orthodontic treatment; f), psychiatric hospitalization 
within one year prior to screening; g) hypersensitivity to 
PBM following patch test.  
Prescreening may occur by telephone or at a clinic visit, 
and it may be combined with the Screening and Baseline Visit (Visit 0). After obtaining verbal consent, 
a brief prescreening interview script will be administered and basic eligibility information, specific points 
of medical history, and contact information will be recorded. If a participant expresses interest in the 
study and if the participant is eligible, the participant will be scheduled for Visit 0. 
6.4 Clinical visits – Those participants eligible after CATI will be scheduled for a pre-randomization 
visit (V0), six treatment visits (V1 to V6) as described in Figure1 and Table 1. For female participants of 
child bearing age, before the PBM therapy is delivered (V1 to V6), a pregnancy test will be performed. If 
the pregnancy test shows a positive result, the participant will be withdrawn from the study. The costs 
of these tests will be covered by the study sponsor. The procedures to be completed in each visit are 
depicted in Table 1 
V0 – Pre-Randomization visit will include informed consent and completion of a detailed medical history 
to confirm, followed by a clinical exam to confirm TMD case status according to the Diagnostic Criteria 
for TMD (DC/TMD). The patient will continue in the study if they meet the criteria for myalgia, with or 
without arthralgia. As part of the DC/TMD, all participants will perform a Standard Movement task 
(SMT) to determine their range of motion and pain upon movement. These tasks are standardized 
components of the DC/TMD and include measures of pain-free mouth opening, maximum unassisted 
mouth opening, and maximum assisted mouth opening. Pain is assessed during the last two 
maneuvers using a visual analog scale (VAS 0-100). 
Following the clinical exam, an experienced trained lab technician will perform a well-validated 
psychophysical measure of pressure pain sensitivity.  Pressure Pain Threshold (PPT) will be assessed 
with a handheld algometer bilaterally at temporalis, masseter, TMJ, trapezius, and ulna as in our prior 
studies. We will also conduct a patch test of the PBM treatment to ensure that the participant shows no 
hypersensitivity to PBM. This will involve brief application of the PBM treatment at a few different skin 
sites, and participants will be asked to report any adverse effects at 15 minutes and 48 hours after the 
test. Individuals who experience moderate to severe skin sensitivity, nausea, fatigue or dizziness after 
the patch test would be excluded from the study. All participants will be instructed to fill out a week-long 
Daily Symptom Diary over the phone or on the computer. They will rate their average pain intensity and 
their worst pain intensity each day on a numeric rating scale (0 = no pain, 100 = worst pain imaginable), 
as well as their pain interference.  Also, they will be instructed to log any rescue medication used to 
control pain related to TMD.  
V1 – Randomization Visit. The following criteria will be required for trial eligibility after the week prior to 
randomization: (1) a minimum of 4 of 7 diary entries were completed, and (2) the mean worst pain 
intensity score for the week was ≥30 of 100.  

Participants who meet the criteria will then be 
block randomized to Active versus Sham 
PBM. The intervention will then be delivered 
by a trained operator that will be blind to the 
TMD diagnosis and the type of treatment to 
be delivered.  
V2 - V5 – Treatment Visits. The patient will 
receive one minutes of the assigned 
treatment in each of the 42 points/areas (see 
Photobiomodulation therapy protocol section 
for more information). Whenever possible, V2 
will be scheduled within 5 days from V1 and 
V3 within 5 days from V2.  
V6 – Final Treatment and Post-Treatment Assessment. The final treatment will be administered, 
followed by completion of the Pain, Enjoyment, General Activity (PEG) Scale and the same movement 
and PPT measures as in V0. Also, the post-treatment blood draw will be collected at this session, and 
the participant will be reminded about the follow-up assessments.  
6.5 Outcome Measures (see Table 2)  
The primary outcome measure will mean one-week pain intensity from the Daily Symptom Diary, 
comparing the one-week average prior to randomization to the one-week average for the week 
preceding V6. 
Secondary outcome measures will include: 
a) Pain during jaw function, which will be evaluated by comparing the pain Intensity score from the 
Standard Movement Task (SMT) from V1 with the pain intensity score from the SMT at V6.  
b) To assess clinical pain and interference, participants will complete the Pain, Enjoyment, General 
Activity (PEG) Scale, a three-item instrument 
assessing average pain intensity and 
interference of pain with general activity and 
enjoyment of life over the past week.  
c) The effect of PBM on circulating cytokines 
measured using Milliplex assay with blood 
collected at V0 (Baseline pre-randomization) 
and V6 (Post PBM treatment). The control 
variables for each outcome and Mediator 
Variables are depicted in Table 2 (also, see 
the Data Analysis section).  
6.6 Photobiomodulation Therapy Protocol 
PBM has been used clinically in the treatment 
of musculoskeletal and other pain conditions 
for over 30 years. Despite the low quality of 
the existing evidence, PBM has been 
increasingly used in other countries for the 
treatment of TMD. However, in the US PBM is 
not widely used for the treatment of TMD pain. 
Due to the multifactorial nature of chronic TMD 
pain, we propose that a multimodal PBM 
protocol targeting multiple pathophysiological 
Table 1. Table of Events 
Procedure 
CATI 
V0 
V1 
V2 
V3 
V4 
V5 
V6 
Inclusion/exclusion 
criteria 
X 
X 
 
 
 
 
 
 
Informed consent 
 
X 
 
 
 
 
 
 
Medical history 
 
X 
 
 
 
 
 
 
RDC 
 
X 
 
 
 
 
 
X 
SMT 
 
X 
 
 
 
 
 
X 
PPT 
 
X 
 
 
 
 
 
X 
Pregnancy test 
(women only) 
 
 
X 
X 
X 
X 
X 
X 
DSD between visits 
 
X 
 
 
 
 
 
X 
PEG Scale 
 
X 
X 
X 
X 
X 
X 
X 
PBM/Placebo 
 
 
X 
X 
X 
X 
X 
X 
Blood draw 
 
 
X 
 
 
 
 
X 
Table 2 – Outcome Table 
 
 
Control Variables 
Primary outcome: 
Pain Level Change with PBM 
treatment 
Average daily pain from Daily Pain 
& Symptom Dairy over one week 
prior to V1 will be compared to the 
average daily pain one week prior 
to V6 
• Demographics (age, race, 
sex) 
• Concomitant medication 
Secondary outcome 
 
TMD Function 
Pain Intensity during SMT will be 
compared between V1 and V6 
• Demographics 
• Concomitant medication 
Pain sensitivity  
PPT during V1 will be compared to 
PPT during V6 
• Demographics 
• Concomitant medication 
Effect of PBM on circulating 
cytokines  
Levels of circulating cytokines will 
be measured using Milliplex assay 
with blood collected at V1 
(Baseline) and V6 (Post PBM 
treatment) 
 
• Cortisol 
• Time of visit 
• Concomitant medication 
 
Mediator Variables 
Inflammation 
Change in cytokine pre-post 
treatment 
Pain Sensitivity 
Change in PPTs pre-post 
treatment 
PBM: Photobiomodulation; SMT: Standard Movement task;  
PPT: Pressure Pain Threshold.  

mechanisms will be the optimal approach for PBM implementation in patients with TMD. Therefore, we 
are proposing to use a 30-45 minute protocol developed by Dincher, ME and Carrol, James (Thor CEO 
and Consultant to this project) which recommends the following sequence (Table 3): we will first apply 
PBM (LLLT and LED) to neuronal targets to suppress nociceptive peripheral afferent input to the spinal 
cord and trigeminal nucleus by treating the dorsal root ganglia associated with the dermatome(s) where 
the pain is experienced, including ganglia both rostral and caudal to the affected dermatome. Also, we 
will target autonomic ganglia in the cervical chain, blood, and lymphatic tissue areas. Treatment of the 
sympathetic ganglia is intended to modulate the sympathetically-mediated enhanced pain. Also, 
treatment of these ganglia has been shown to reduce inflammation. Finally, PBM/LLLT will target the 
painful musculoskeletal tissue associated with palpable tender points. Tender points will be located by 
digital palpation of the muscle that is the primary source of pain for each individual, and a tender point 
will be identified as a taut band that produces familiar pain upon palpation. We hypothesize that this 
multi-wavelength PBM protocol that targets different pathophysiological mechanisms will produce 
significant and long-lasting analgesic effects.  
PBM parameters: We chose the THOR® laser system given because their active treatment arm uses 
both coherent laser and monochromatic LED light. Therefore, we will use three types of active probes 
in this investigation including, A) Single Laser 810 NM 200 mw; B) Laser Cluster of 810 NM equivalent 
to 1 WATT and; C) LED Cluster, 34 X 660nm at 10 mw and 35 850nm, 30mw 1390mw total. As 
detailed in Table 3. We propose to use these three PBM probes in concert for the treatment of TMD 
pain. Laser A (Single Diode Laser) is designed for isolated trigger points and superficial muscles. Laser 
B (Cluster Laser) is designed for a more diffuse treatment area, targeting analgesia, anti-inflammatory, 
and deep tissue repair. Laser C (LED Cluster) is purportedly designed for the presence of diffuse 
inflammation. Another reason that we propose the use of THOR®, it is because of their newly 
manufactured Clinical Trial Device, which includes a credible sham condition, which effectively 
maintains the blinding of both the patient and the interventionist.  
Sham PBM:  When applying PBM therapy, 
there are some heating elements in the 
treatment device, and most of the sham 
treatment devices available do not offer this 
feature, which increases the likelihood of 
unblinding both the patient and the 
interventionist. The THOR® LX2.3 PBM 
machine includes this new feature, such 
that the sham condition mimics the heating 
activity of the active treatment. Treatment 
Codes: Another feature of the THOR® LX2.3 
is that the machine comes with a Sham 
Switch Box that allows the assignment of 
numeric codes for sham and active 
treatment. The interventionist simply enters 
the code but is unaware of whether it is 
assigned to active or sham treatment, as the statistician maintains the code list. Sham Concealment 
Goggles: Proper protective eyewear that absorbs the damaging radiation will be worn by staff as well 
as by participants during both active and placebo therapy. The patient goggles also emit LED light 
inside (behind the lenses), which prevents them from discerning sham versus active treatment. There is 
a lead which plugs into a socket on the Placebo Switch Box to power the LED when the treatment 
device turns on. Therefore, only the THOR goggles will be worn, no substitutes. They meet the 
necessary laser safety requirements and they prevent potential “unblinding” of treatment assignment. 
 
Areas of treatment: Target areas for the treatment will include trigger points on temporalis, masseter, 
sternocleidomastoid, occipital and trapezius (Laser A); Neuronal blockage of trigeminal area, spinous 
process of C2-C6, broad muscle trapezius and occipital (Laser B); and finally blood and lymphatic 
areas of preauricular, occipital, and superficial and deep cervical (LED). These treatment targets are 
Table 3; Laser Devices and Parameters 
Type of probe 
Dose and 
Dose Rate 
Treatment 
Intend 
Single laser –Laser A: 
810nm 200mw 
6-12 Joules 
(J) 
continuous, 
firm contact 
Tender points  
Laser Cluster –Laser 
B: 810nm 1W 
6-12 J 
continuous, 
firm contact 
Broad muscle, 
neural blockage 
if ganglions, 3-5 
cm depth  
LED Cluster – LED: 
660nm (10mw x 34) 
aggregate 850nm (30 
mw x 35) 
6-20 J, 20Hz 
firm contact 
Blood, lymphatic 
areas and 
superficial 
neural targets  

based on the most common locations of pain reported by patients with TMD and the putative underlying 
neuronal and inflammatory mechanisms, and they were recommended in the recently developed multi-
wavelength protocol(32) . 
 
6.7 Treatment Assignment Procedures 
 
Randomization Procedures 
Prior to randomization, the inclusion and exclusion criteria will be reviewed, and only participants who 
meet eligibility criteria will continue in the trial. Participants will be randomized in a 1:1 ratio of active 
Photobiomodulation to Sham-PBM within prespecified blocks. Randomization will be accomplished by a 
web-based randomization system developed and maintained by the study statistician. At the time of 
randomization, study staff, who will remain blinded to treatment assignment, will access the system, 
enter the participant’s study identification number, and verify that the participant is eligible for 
randomization. The system will assign a randomization code that will be entered in the randomization 
box in the PBM machine. The code will determine whether the participant receives sham or active PBM 
treatment according to the participant’s treatment assignment. 
 
Blinding Procedures 
All study staff, including the study clinicians and investigators, will be blinded to the participants’ 
treatment assignments throughout the data collection period. The THOR® LX2.3 PBM machine 
includes this new feature, such that the sham condition mimics the heating activity of the active 
treatment. Treatment Codes: Another feature of the THOR® LX2.3 is that the machine comes with a 
Sham Switch Box that allows the assignment of numeric codes for sham and active treatment. The 
interventionist simply enters the code but is unaware of whether it is assigned to active or sham 
treatment, as the statistician maintains the code list.  
Sham Concealment Goggles: Proper protective eyewear that absorbs the damaging radiation will be 
worn by staff as well as by participants during both active and placebo therapy. The patient goggles 
also emit LED light inside (behind the lenses), which prevents them from discerning sham versus active 
treatment. There is a lead which plugs into a socket on the Placebo Switch Box to power the LED when 
the treatment device turns on. Therefore, only the THOR goggles will be worn, no substitutes. They 
meet the necessary laser safety requirements and they prevent potential “unblinding” of treatment 
assignment. The project staff will remain blinded through the analysis for the primary objective. If 
oversight boards, such as the IRBs or Data and Safety Monitoring Board (DSMB), request an unblinded 
data report during the data collection period, the unblinded biostatistician will generate the report. 
 
Unblinding Procedures 
Unblinding before the study is completed will occur only if a participant’s well-being is threatened and is 
necessary to protect the participant. Study participants will be provided with instructions and contact 
information for emergency situations. 
 
6.8 Inflammatory markers: We propose to assay a panel of circulating cytokines pre vs. post 
treatment (V1, V6). Based on work performed by Slade et al, we plan to examine multiple inflammatory 
mediators, such as MCP-1, IL-1ra, and IL-8, IL-6, IL-1β, IL-10 and TNF-α, as these inflammatory 
mediators are considered to play a crucial role in TMD pathophysiology and pain sensitivity.  Also, we 
also plan to measure cortisol level as evidence suggests that cortisol can influence the immunological 
response. Therefore, we plan to include cortisol levels as a control variable when analyzing the 
cytokine data. Given that our biomarker assays will be completed at the end of the project, the final 
panel of biomarkers to measure will be determined at that time based on the best available evidence. 
 
6.9 
Strategies for Recruitment and Retention 
We propose to enroll 120 individuals 18 years and older who meet DC/TMD criteria for myalgia, with or 
without arthralgia. We will recruit using community-based recruitment as well as clinic-based 
recruitment. Our recruitment strategy will be developed and implemented with support from the 
Recruitment Center of our Clinical and Translational Science Institute (CTSI). The CTSI Recruitment 

Center assists with drafting recruitment plans, developing recruitment materials (e.g. flyers, online ads), 
using social media for recruitment and linking with other local and national recruitment resources. We 
have worked with the CTSI Recruitment Center on several previous projects, including our SOPPRANO 
clinical trial Study. 
Community-Based Recruitment: Alachua County, Florida has a population of 269,956 people, 72% of 
which are 18 years and older. Racial/ethnic diversity is substantial, with 20.6% of residents being 
African American, 10.3 Hispanic, and 60.8% non-Hispanic white. The University of Florida has a large 
footprint in the community, which facilitates recruitment into research protocols. Our community-based 
recruitment methods may include any of the following strategies.  We will advertise around our local 
institutions as well as throughout the local communities, including advertisements in local retail 
establishments, at bus stops and on buses, and in local print media. Also, we will participate in 
community health fairs and education programs sponsored by entities within our University. We have 
participated in many such events in the past, which have been highly successful. Fourth, we will 
leverage existing CTSI recruitment resources, including HealthStreet and UFHealth Study Listings. 
HealthStreet is a community portal of entry for linking and navigating underrepresented populations to 
opportunities to collaborate with the research community through town halls, focus groups, individual 
interviews, library use, individual health assessment, and navigation to appropriate research. 
HealthStreet’s Community Health Workers engage with residents to assess health needs and enroll 
interested individuals in a research registry.  
Clinic-Based Recruitment:  Patients may also be recruited from the UF College of Dentistry Faculty 
Practice and Student Clinics, where patients with TMD are often evaluated and treated. In addition, we 
will identify potential participants through the CTSI’s Integrated Data Repository, which contains de-
identified data from the electronic health record. This allows for cohort identification, and UFHealth has 
implemented consent-to-share, such that a large proportion of patients seen in our clinics have 
provided consent to be contacted about research. If a sufficient number of individuals are identified in 
the IDR, we may request a list of all individuals with a TMD-related diagnosis who have provided 
consent to share, whom we can then contact directly to determine their eligibility and interest for 
participation in the study.  
Retention: We are overenrolling by 20% to account for attrition. Retention in our previous SOPPRANO 
Study was 87%, even though this was a more intensive and lengthy protocol. That is, SOPPRANO 
included 6 study visits over a 12-week period, with daily medication intake and completion of daily 
diaries throughout the protocol. Thus, given the significantly shorter duration of the current protocol, 
and 80% retention rate is quite conservative.  
 
6.10. Data Analysis 
 
Sample Size Justification. For the primary endpoint VAS, we assume the standard deviation (SD) is 
1.96 cm and effect size is 2.5 cm. We plan to recruit 120 subjects (60/group). Assume 15% attrition 
rate, we will have 102 subjects (51/group) for the analysis at the end of the study. The statistical power 
with two-sided type I error rate of 0.05 is 100% based on a two-sample T test. For the secondary 
endpoint IL6, we also have 100% statistical power to detect the effect size of 2.2 (on the natural-log 
scale) estimated from pilot data.   
 
Overall Data Analysis: Descriptive statistics, specifically measures of central tendency (mean, median) 
and dispersion (variance, interquartile range), will be calculated for all continuous measures. 
Descriptive statistics will be calculated by group and histograms will be used to compare the 
distributions. Intent-to-treat analysis will be used to test the treatment efficacy. Missing data (if any) will 
be handled with multiple imputation and sensitivity analysis. The data analysis for each aim is 
described below: 
 
SA1: To investigate the analgesic efficacy of multi-wavelength PBM protocol [810nm 200mw; 
810nm 1W aggregate and 660nm (10mwx34) aggregate 850nm (30mw x 35) LED] versus placebo 

in patients with chronic TMD. H1a: compared to a credible placebo condition, the proposed PBM 
protocol will significantly reduce TMD pain.  
 
For H1a: To evaluate the change in TMD related pain after PBM/Placebo treatment, the variable will be 
assessed using a 0 to 10 numerical rating scale (NRS, 0 = no pain, 10 = worst pain imaginable) for the 
average pain. Average daily pain from Daily Symptom Dairy averaged over one week prior to 
randomization will be treated as the baseline variable. The average daily pain one-week prior to Visit 6 
will be treated as the primary endpoint. Linear regression model will be employed to test the association 
between VAS and treatment group (PBM vs Placebo). This approach will allow us to control for 
potential confounders (e.g. psychological factors). We will also try linear mixed effect model (LMM) to 
handle repeated measurements. An advantage of LMM is that it can provide valid estimates if there are 
missing data that are missing at random. An alternative to LMM is GEE to analyze the repeated 
measurements in relation to the treatment groups. Interactions between group and baseline 
inflammatory response will also be explored.  
SA2: To investigate whether PBM changes inflammatory responses and mechanical pain 
sensitivity in patients with TMD and to determine the association of these changes with the 
analgesic response. H2a: the PBM protocol used will reduce the amount of circulating pro-
inflammatory cytokines and will increase mechanical pain thresholds. H2b PBM-induced changes in 
inflammation and pain sensitivity will be associated with the magnitude of reductions in clinical pain 
following PBM. 
 
For H2a: These secondary endpoints including cytokine and pain sensitivity will be analyzed in the 
same way as the primary endpoint in H1a where baseline values and potential confounders such as 
psychological factors and cortisol level will be adjusted in the model. For H2b, we will use potential-
outcomes (PO, i.e., counterfactual-outcomes) mediation analysis approach to estimate and test the 
mediation effect of the inflammation and pain sensitivity. PO mediation analysis is more flexible than 
traditional mediation analysis approach in terms of allowing interaction between independent variable 
and mediators and non-linear indirect effects. In the mediation model, treatment is the independent 
variable, inflammation and pain sensitivity will be the mediators and the outcome variable is VAS. 
Baseline values and potential confounders will be adjusted in the mediation model.  
7. Possible Discomforts and Risks:  
RDC Exam. Assessments of muscle and TMJ sensitivity to digital palpation during the TMD 
examination, are designed to evoke brief pain or discomfort during application of the stimulus; however, 
the results are not long lasting or damaging to the affected tissues. This increase of pain normally is 
short lived and controlled by over the counter pain medication.   
Pressure testing. Pressure is delivered by a hand-held algometer (spring-controlled device delivering 
calibrated pressure via a flat 10mm diameter rubber tip). Pressure is delivered at an approximate rate 
of 30 kPa/sec. Participants will be instructed to signal by pressing a button when the pressure 
sensation first becomes painful at which time the researcher removes the algometer. There is little 
opportunity for bruising or other transient trauma from this procedure. All tests will end upon completion 
of the modality or upon the participant’s request, whichever comes first. 
Questionnaires. A participant may experience discomfort associated with being asked personal 
questions about her or his health history, symptoms, or emotional feelings. Participants will be told that 
they may choose not to answer any questions that cause discomfort 
PBM therapy. The therapy should produce minimum discomfort other than a light warmth or heat on the 
area where the light is being applied. If the patient feels uncomfortable, he/she can stop at any time. All 
interventionists and patients will be provided with goggles to protect their eyes from the light. Treatment 
on the head and neck with high irradiance laser may cause pain as the melanin in the fine superficial 
hair follicle absorbs a lot of the laser energy. If treatment becomes painful, we will remove the treatment 
probe from contact and treat ~15mm from surface of skin. 

Blood Collection. There is a possibility of mild pain and bruising associated with a blood draw. Trained 
personnel will perform the blood collection using standard procedures. 
Adequacy of Protection against Risks. 
Our inclusion and exclusion criteria are designed to minimize risks to participants.  
A total of 120 adults with TMD, (Masticatory Muscle Disorders, 1A: Myalgia) age 18 and older will be enrolled. 
Similar to our previous work, the inclusion criteria for participants are:  
• Provides a signed and dated informed consent form 
• Is at least 18 years of age (male or female and any race or ethnicity) 
• Meets diagnostic criteria for TMD, (Masticatory Muscle Disorders, 1A: Myalgia) 
• Has experienced facial pain for at least 3 months 
• At Screening and Baseline Visit (Visit 0), reports an average pain intensity rating over the past 
week of ≥ 30 on a numerical rating scale (0-100) 
 
Participants will be excluded if they have any concurrent medical conditions that could confound 
interpretation of outcome measures, pose a safety risk for any of the assessment or intervention 
procedures, or preclude successful completion of the protocol. Specific exclusion criteria are:  
• 
Starting a new daily prescription medication for the management of pain within 30 days prior to 
treatment session; 
• 
Use of any injection therapy (e.g., tender or trigger point injections, steroid injections) for the 
management of pain within 2 weeks prior to the CATI;  
• 
Starting occlusal appliance therapy within 30 days prior to CATI; d) history of facial trauma or 
orofacial surgery within 6 weeks prior to CATI; 
• 
Active orthodontic treatment; 
• 
Psychiatric hospitalization within one year prior to screening.  
• 
Has known hypersensitivity to laser therapy. 
• 
Currently being treated with chemotherapy or radiation therapy 
• 
Has been treated with another investigational drug or treatment within 30 days prior to the 
Screening and Baseline Visit 
• 
Is pregnant or nursing 
• 
Anything that, in the opinion of the investigator, would place the participant at increased risk or 
preclude the participant’s full compliance with or completion of the study 
 
Protection against Risk.  
Protection against risk to confidentiality. Information collected as part of this research protocol will be 
maintained in locked filing cabinets and password protected databases accessible only to study 
personnel. All study staff will be trained in handling human subject information to maintain privacy and 
confidentiality. Procedures for allowing access to investigators to use this information for research will 
be under the authority of the PI and will follow HIPAA compliant guidelines for the release of PHI.  
No results will ever be reported in a personally identifiable manner. All research data will be entered 
directly into a web-based survey that is maintained by the University of Florida CTSI (REDCap). The 
data will be stored on secure servers at the University of Florida and will be accessible only to trained 
study personnel.  
Protections of risks related to study questionnaires. To minimize any risks related to emotional 
responses to questionnaires, persons will be informed about the types of questions included in the 
surveys, which are similar to the types of questions persons might be asked by their doctor in a clinical 
setting. They will be informed that they can refuse to answer any questions if they so choose. 

Protection of risks related to PBM Laser. PBM therapy and the Thor system has shown minimal side 
effects.  THOR lasers have divergent beams but are potentially harmful if viewed directly from a 
distance of less than 1.1 meters.  Proper protective eyewear that absorbs the damaging radiation will 
be worn by staff as well as by participants during both active and placebo therapy. Participants will be 
instructed not to take the goggles off until the treatment is completely off. In addition, the laser will be 
tested in a small area before proceeding to insure the participant’s skin is not sensitive to the light. To 
minimize risk associated, participants will be monitored throughout treatment sessions and asked to 
report any discomfort. If they experience any uncomfortable sensations the treatment will be stopped. 
All PBM sessions will be administered and continually supervised by a trained experimenter. The above 
symptoms have only been reported when participants are in the active treatment group.  
Data and Safety Monitoring Plan 
 
The Study team will meet at least quarterly to review adverse events and enrollment progress. 
The Study Team will closely monitor all adverse events (AEs) on a continuous basis and we will report 
any AEs to the IRB per current policies and guidelines.  
8. Possible Benefits:  
There may or may not be direct benefit to subjects for participation in the study. Some patients could 
benefit from reduction of pain during the trial and this pain may return after the trial is over.  In an attempt 
to reduce pain related to TMD as well as decrease the overuse of pain medication, this search for an 
efficacious, safe, and affordable treatment may benefit many TMD patients in the future.  
Importance of the Knowledge to Be Gained 
The information obtained will provide novel and important information regarding the benefits non- 
pharmacological treatments for TMD  
 
9. Conflict of Interest 
 
The PIs of this research, Dr. Margarete Ribeiro-Dasilva and Dr. Roger Fillingim do not have any conflict 
of interest.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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