Bruxism, temporomandibular disorders and consequences in patients with Parkinson*s disease

The results of a recent questionnaire-based study suggest that bruxism and
temporomandibular disorders (TMD) are more prevalent in Parkinson*s disease
(PD) patients than in controls. Bruxism and TMD could be influencing patient
satisfaction and quality of life, which is already negatively influenced by
having PD. This clinical longitudinal study is designed to more objectively
confirm the prevalence of bruxism and TMD in PD patients. Furthermore, factors
will be identified which influence the association between bruxism and TMD on
one hand and for example severity of the disease and medication use on the
other hand. An important consequence of bruxism is tooth wear. Therefore, it is
helpful to know whether increased tooth wear is present in patients with PD.
And also whether the confounder of tooth wear (saliva) deviates from standard
values. But most importantly, we need to know more about this possible relation
between tooth wear and PD, because tooth wear can negatively influence the
quality of life. By increasing awareness of this possible risk, dentists will
be able to prevent extensive restorative work.

Primary objective: To investigate the prevalence of bruxism and TMD in PD
patients through objective measurements and to identify factors associated with
a higher risk of developing these symptoms.

Secondary objectives:
- To investigate the salivary flow in patients with PD.
- To investigate whether the salivary flow, the pH, and the buffer capacity in
patients with PD is related to the severity of tooth wear and if this is
different in patients with(out) bruxism.
- To investigate whether PD patients with bruxism differ in brain
pathophysiology compared to PD patients without bruxism.

Observational study design

study procedures will be combined as much as possible with regular visits to
the outpatient clinic for movement disorders at the VUMC. During an appointment
with the neurologist, patients will be informed about the study. A week later
they will be called by the investigator with the question if they want to
participate. Participants will fill out a research questionnaire (±30 min) and
be examined clinically (±40 min). Subsequently, all patients will be asked to
sleep for 5 nights with a one-channel EMG mobile device (GrindCare® GC3+) at
home and to use the Bruxism app (BruxApp®) during wakefulness, to confirm the
diagnosis of bruxism. Patients who already visit the VUmc, and filled in the
questionnaires >1 year ago are requested to repeat this procedure (60min).
Short-term risks of the clinical examination include possible mild muscle pain
and fatigue in the masticatory muscles. This will be minimalized through short
intermissions when needed. In addition, in some patients, the gel pad of the
GrindCare® GC3+ can cause reversible skin irritation. There are no long-term
risks associated with this study. Patients with a pacemaker cannot use the
GrindCare® GC3+ and are excluded for that part of the study.