Evaluating the Effects of a Removable Dental Mouthpiece on Symptoms Associated With Parkinson's
Phase: NA
Conditions: Parkinson Disease
Sponsor: Washington University School of Medicine

Dental Appliance for Parkinson Disease (DAPD) 
 
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Official Title: Dental Appliance for Parkinson’s Disease 
NCT Number: 04082663 
Document Date:  April 23, 2019 
 

Dental Appliance for Parkinson Disease (DAPD) 
 
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I. SPECIFIC AIMS 
The primary objective of this study is to determine if the use of a dental mouthpiece can improve 
gait and motor signs and symptoms, sleep, or quality of life for people with Parkinson’s disease 
(PD).  We will conduct a pilot study with participants who have been diagnosed with PD 
recruited from the community. For this study, participants will have one in-person study visit 
where they will be fitted with a dental mouthpiece and complete motor tests while wearing the 
mouthpiece and while not wearing the mouthpiece. Participants will also complete sleep 
questionnaires and quality of life questionnaires. Participants will then be asked to take the 
mouthpiece home and wear it at night while they sleep and during the day, except while eating, 
for one month. At the end of the month, they will complete the same sleep and quality of life 
questionnaires administered remotely by mail and answer questions about their experience with 
the dental mouthpiece.  
 
Specific Aim 1: To determine the immediate effect of a dental mouthpiece on Parkinsonian gait 
and motor symptoms. A 4.8m GAITRite (CIR Systems, Inc., Franklin, NJ) will be utilized to 
quantify gait mechanics with and without mouthpiece use. Gait and balance tasks will be 
assessed.   
Hypotheses: 
a. People with PD will show improvements in gait speed with the mouthpiece in place 
compared to without. 
b. People with PD will show improvements in balance with the mouthpiece in place 
compared to without. 
 
Specific Aim 2: To determine the longer-term feasibility of use and effect of dental mouthpiece 
on sleep and quality of life (QOL) for people with PD.  
Hypotheses: 
a. People with PD will show improvements in sleep quality and duration after one 
month of wearing the mouthpiece as compared to baseline.   
b. People with PD will show improvements in health-related quality of life after one 
month of wearing the mouthpiece as compared to baseline.   
 
II. BACKGROUND AND SIGNIFICANCE 
For people with Parkinson’s disease (PD) advances in medical treatments have 
increased lifespans but have not effectively mitigated the decline in function and the 
characteristic signs and symptoms of the disease.1, 2 People with PD often report disturbances in 
sleep, activities of daily living, and general quality of life. Gait and balance dysfunction are 
known to negatively affect quality of life in this patient population and are considered risk factors 
for falls.3 Walking ability appears to be particularly important in this population, as impairments 
in ambulation tend to precede impairments with other gait-dependent activities.4   

Dental Appliance for Parkinson Disease (DAPD) 
 
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Several clinical reports and case studies have shown assorted benefits from use of a 
dental mouthpiece in people with PD. Specific characteristics of these mouthpieces differ 
somewhat across cases, but the mouthpieces are typically modeled after those used for 
temporomandibular joint disorder. A clinical report for one woman with PD showed 
improvements in grip strength and subjective improvements in motor function and quality of life 
while using a mouthpiece.5 This report relied on observation for determining improvements in 
motor function and did not report a formal quality of life measure or questionnaire. In another 
case report, a participant subjectively reported use of a bruxism splint improved their sleep 
quality and fatigue levels.6 However, again, no quality of life or sleep measures were reported.6 
A more recent case study found some objective improvements in selected gait and 
balance measures in a participant with PD while using a dental mouthpiece.7 The Four Square 
Step Test and grip strength in the non-dominant hand showed significant improvements with the 
mouthpiece compared to the patient’s baseline condition without the mouthpiece. Additionally, 
this participant reported significant increases in quality of life while using the mouthpiece, as 
evidenced by significant improvements in Parkinson Disease Questionnarie-39 (PDQ39) and 
Global Rate of Change Scale. The researchers reported the participant’s gait mechanics 
differed with use of the mouthpiece, with the participant holding his arms closer to midline.7 
The mechanism underlying the mouthpiece’s effect on gait and motor function is not well 
understood. It is possible that because afferent inputs from the trigeminal nerve project to the 
nucleus raphe of the reticular formation, abnormal input from the mandibular branch of the 
trigeminal nerve may affect rhythmic motor function and balance.8  Stimulation of the nucleus 
raphe can produce rhythmic contractions of muscle groups which could potentially affect gait 
and posture.8 A mouthpiece may function to promote a more optimal maxillomandibular vertical 
interrelationship and reduce irritation or abnormal feedback from the mandibular branch of the 
trigeminal nerve, or more specifically the auriculotemporal nerve, to the nucleus raphe.9  
Current knowledge regarding the effects of a mouthpiece on motor function and quality 
of life in people with PD is limited by slight variance in design between mouthpieces and by the 
small number of participants studied thus far. Our understanding of the topic is based on a small 
handful of clinical reports and case studies. By conducting an exploratory pilot study, we will 
examine whether a mouthpiece can affect motor symptoms and gait in a larger group of 
participants with PD. Additionally, we will determine whether use of a mouthpiece can improve 
sleep and quality of life in people with PD. Donald R. Moeller, DDS, MD, MA, ThM will custom 
fabricate the mouthpieces for this study. Dr. Moeller has authored several peer-reviewed, 
journal-published studies in which he fabricated mouthpieces to treat various symptoms 
resulting from neurological disorders.10,11   
 
III. METHODS 
Participants 
Participants will be recruited from the community.  
For inclusion in the study, participants must:  
(1) have a diagnosis of idiopathic, typical Parkinson Disease according to the UK Brain 
Bank Criteria, Hoehn & Yahr stages 1-3; 

Dental Appliance for Parkinson Disease (DAPD) 
 
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(2) stable PD medications for the two weeks prior to baseline visit;  
(3) be able to walk at least 10 meters at baseline with or without an assistive device;  
(4) have their own teeth and/or dentures;  
(5) be willing to try to wear a mouthpiece for one month;  
(6) are over the age of 30; and 
(7) provide written or verbal informed consent.   
Exclusion criteria include:  
(1) pre-existing medical conditions that would inhibit full participation in the study’s tasks;  
(2) absence of any dentition;  
(3) cognitive impairments indicated by Mini Mental Status Exam (MMSE) score of <24;  
(4) freezing of gait which moderately or severely impacts walking; or 
(5) current use of an oral appliance (e.g., a dental mouthpiece, retainer, or braces). 
 
Measures and Materials 
The MMSE will be administered to ensure absence of cognitive impairment.  The New Freezing 
of Gait Questionnaire (nFOG) includes participants watching a short video about freezing of gait 
and a questionnaire about whether they experience freezing of gait and if so, questions that 
help describe the types of freezing of gait they experience. 
Mouthpiece 
Each participant will be fitted with a maxillary orthotic (mouthpiece) fabricated by Dr. Moeller.  
The process for fabrication of the mouthpiece will be as follows: 
1) The participant is seated in a normal straight-backed chair with feet on the floor. 
2) A dental impression tray is sized appropriately for the participant’s lower jaw to ensure 
that no impingement of soft tissue structures occurs. 
3) A quick setting dental alginate impression material is mixed for one minute and then 
placed into the dental impression tray. 
4) The dental impression tray is filled with the alginate material, and the tray and material 
are placed into the participant’s mouth. 
5) The tray will remain in the mouth approximately 1 to 2 minutes and will then be 
removed. 
6) A fast setting dental stone is placed in the tray. 
7) The dental stone is allowed to set for one-half hour in the alginate impression. 
8) The dental stone model is removed from the alginate impression.  
9) The lower jaw model is trimmed and then taken to the dental vacuum former machine 
where a poly-vinyl-acetate (medical-dental grade) thermoplastic sheet of material is 
heated to a temperature to allow deformation of the material. 

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10) The vacuum is turned on and the thermoplastic material is sucked down over the 
dental stone model. A small 5 mm wide strip of thermoplastic material is placed directly 
over the occlusal portion of all the mandibular teeth to act as a reinforcement. 
11) The thermoplastic material is cooled to below room temperature with cold water until 
stiff. 
12) All thermoplastic material which approximates any structure but the dental hard 
tissue (teeth) is removed from a height just above the attached gingival tissue so that the 
mouthpiece will be entirely tooth borne. 
13) The occlusal material is adjusted at chairside so that an even continuous contact 
with the maxillary teeth is created on all teeth from the rear-most molar teeth including 
anterior teeth. The mouthpiece will then have the general appearance of a "horse shoe" 
in shape. 
14) All areas which contact oral soft tissue on the perimeter of the device will be 
smoothed to allow placement without any trauma or discomfort to any tissue in the 
participant’s mouth. 
15) The mouthpiece will be placed in the participant’s mouth for a period of about ten 
minutes to ensure there is no interference with any normal jaw and biting movements. 
The mouthpiece is fabricated with polyvinyl ethylene acetate which is non-toxic to humans.  
There are similar mouthpieces sold over the counter by pharmacies for patient use without a 
physician/dentist’s prescription.   
Participants will be instructed to return the mouthpiece at the end of the study period.  
Motor assessments 
Movement Disorder Society-Unified Parkinson’s Disease Rating Scale Part III (MDS-UPDRS-III) 
Motor subsection will be used to assess disease severity.   
The GAITRite system will be used to assess gait performance. The GAITRite is a portable 
electronic walkway mat (600 cm long and 64 cm wide). All participants will walk along the mat 
so that imbedded sensors are activated by foot pressure and deactivated when pressure is 
released. A computer will process the footsteps for gait velocity (cm/s). The mat is located in a 
well-lit room, with starting and ending limits marked one meter from the mat to prevent recording 
acceleration and deceleration phases.   
Balance will be assessed using the Mini-BESTest. The Mini-BESTest is a 14-item evaluation 
designed to assess a variety of balance components.   
Quality-of-life questionnaires 
Parkinson’s Disease Questionnaire-39 (PDQ-39) contains 39 self-report items designed 
specifically for people with PD. There are eight subscores that are calculated along with a total 
score.  
Parkinson’s Disease Sleep Scale (PDSS) contains 15 self-report items designed specifically to 
assess various indicators of sleep quality in people with PD.  

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Participant information  
Participants will fill out a demographic form, a medication form, and medical comorbidity form at 
the in-person visit, and note any changes in their health or medications after wearing the 
mouthpiece for one month.   
Journal 
Participants will keep a journal documenting how long they wore the mouthpiece at night and 
during the day, reasons for taking it out, and can make comments about the mouthpiece. 
Exit questionnaires 
Participants will complete an open-ended exit questionnaire regarding their experience with the 
mouthpiece and the Global Rate of Change Scale (GRC) after wearing the mouthpiece for one 
month.  
 
Protocol 
A phone screen will be used to screen for preliminary study suitability. If the potential participant 
passes the phone screen and would like to enroll in the study, we will then schedule them for 
their in-person visit. 
The first visit will be in-person on the ground floor of the Movement Science Research Center at 
4444 Forest Park Ave, St. Louis, MO, 63110. The study visit will follow the following schedule:  
Informed consent, MMSE, nFOG (15 minutes): A trained researcher will review the informed 
consent document with the participant, outlining the study objectives and ensuring the 
participants have the opportunity to ask the researcher any questions they may have regarding 
the study and procedures. If the participant wants to continue, they will sign the consent form. 
The MMSE will be performed to screen for cognitive impairments which would affect study 
participation.  The nFOG will provide us with information about freezing of gait if applicable.  
Motor Assessment #1 without mouthpiece (45 minutes): MDS-UPDRS-III, GAITRite, Mini-
Bestest (order will be randomized) 
Dental Measurements (15 minutes): Dr. Moeller will take dental measurements for the purpose 
of creating a custom-fitted mouthpiece as outlined in the Methods section. 
Questionnaires, Medical History, Medications (30 minutes): The participants will complete 
demographic, medical history/medications forms, sleep and quality of life questionnaires while 
their mouthpiece is being fabricated.   
Mouthpiece in (25 minutes): After their mouthpiece has been fabricated and adjusted (smoothed 
as needed), participants will sit with the mouthpiece in for 25 minutes. 
Motor Assessment #2 with mouthpiece (45 minutes): MDS-UPDRS-III, GAITRite, Mini-Bestest, 
(order will be randomized) 
Participants who take medication for Parkinson symptoms, will be asked to take their medication 
30 minutes before arrival to ensure participants are in the “on” phase for the motor tasks.  

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At completion of the in-person visit, participants will be instructed to use the mouthpiece as 
much as possible for the next month. Participants will be informed they can take the mouthpiece 
out while eating and will be instructed to keep track of how long they wear the mouthpiece each 
day by journal entry.  
Follow-up will occur one month later. 
Questionnaires, Medical History, Medications (30 minutes): The participants will complete sleep 
and quality of life questionnaires, record any changes in their medical history or medications, 
and complete an open-ended questionnaire regarding their thoughts on the mouthpiece and the 
GRC.   
Randomization Method 
 
The order in which the motor assessments are given in regards to wearing the mouthpiece or 
not will be randomized for each participant. The motor tasks (disease severity, gait, balance) will 
be randomized within each participant.   
 
Safety and Adverse Events 
 
The research team will do everything possible to ensure safety of all participants over the 
course of this study. The adverse event most likely to occur in this study is risk of falling while 
walking. Participants will be fitted with a gait belt. Members of the research team are trained in 
fall prevention and will closely monitor all participants throughout all aspects of the study in case 
of a need to assist with balance to prevent a fall. In the case of an adverse event, emergency 
medical care will be sought immediately if needed. Any serious adverse events will be reported 
to the local IRB immediately. Occurrence of an adverse event will be noted in a participant’s file.  
 
Potential risks will be addressed in the following ways: 
 
a) Discomfort in answering questionnaires: Participants may refuse to answer any questions 
they prefer not to answer. 
 
b) Loss of confidentiality: Loss of confidentiality is highly unlikely. To safeguard against this, we 
will comply with all HIPAA regulations. Data will not be identified by participant name. All data 
will be coded, and code sheets will be stored in locked files.  
 
c) Stumbling during locomotion: Participants will be closely attended by a trained research staff 
member during walking and fitted with a gait belt. Walking will be performed in a large, open 
space and the staff member will be prepared to assist participants who may stumble.  
 
d) Falling: Participants will be closely attended by a trained assistant who will ensure the safest 
of conditions. It is unlikely that participants will experience falls during testing or will be injured 
as the result of a fall. If a participant appears unsteady, breaks will be encouraged or testing will 
be terminated.  
 
e) Fatigue from walking: Rest breaks will be provided as needed. 
 

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f) Discomfort or irritation while being fitted for the mouthpiece or while wearing the mouthpiece: 
the participants may remove the mouthpiece at any time. 
 
Benefits 
 
We do not yet know the full extent to which the mouthpiece may improve symptoms associated 
with Parkinson disease. This study may help inform future treatment techniques to improve 
motor and non-motor function in people with PD. 
 
Interim Monitoring and Early Stopping 
 
Data will be monitored throughout the study and, should any issues arise, we will adjust our 
protocol and submit any changes to the IRB project for review. We will not conduct interim data 
analyses. 
 
Statistical Analyses Plan 
We will use paired t-tests to determine if there are differences between conditions (with 
mouthpiece vs without mouthpiece). We will also use paired t-tests to compare sleep and quality 
of life questionnaires from baseline (prior to study) to follow up (after one month of mouthpiece 
use). 
R will be used for data analysis across all aims. 
Power 
Because of the exploratory nature of this pilot study and relative lack of information in the 
literature, no formal power analysis was conducted. 
 

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