The purpose of this study is to test whether severe masticatory muscle spasms during sleep (e.g. teeth clenching and grinding, known as "bruxism" in technical jargon) demonstrably decrease after application of botulinum toxin type A (Xeomin®). Xeomin® has so far been used to relieve spasms of other muscles and is an approved drug in Switzerland. This study is now intended to test the suitability of this drug for relaxation of the masseter muscle.
Bruxism is a prevalent condition that differentially burdens individuals. The overall objective of this pilot study is to measure the effects of BTX-A (Xeomin®) injections into bilateral masseter muscles for the management of sleep bruxism and associated symptoms. The hypothesis is that BTX-A reduces masticatory muscle activity. The aim of this study is to instrumentally monitor subjects closely over an extended time period of three months before and after application of BTX-A. Botulinum toxin type A ( BTX A; Xeomin ® ) temporarily blocks neuromuscular synapses. It is successfully and safely used therapeutically in various types of movement disorders and in chronic migraineurs. The mechanism of action of this treatment is related to a reduction of neurotransmitter release leading to reduced muscle activity. The following Null hypothesis will be tested: Injections of Xeomin® into the masseter muscles bilaterally (25 Units per muscle applied with 2 injections in each muscle) have no effect on bruxism measured by A) Masticatory muscle activity (1° objective) B) Subjects' well-being (2° objective) C) Sensitivity of masticatory muscles and jaw joints (2° objective) D) Anxiety over tooth wear (2° objective) E) Disturbed sleep by bed partner (2° objective) Following instruments will be used: 1. WISE questionnaires. A comprehensive web-based interdisciplinary symptom evaluation tool. 2. Algometer for sensitivity measure of masticatory muscles and jaw joints. 3. Bio-signal recorder. Parallel to the Electromyography (EMG) of the masseter muscles, other bio-signals such as a number of electroencephalographic (EEG) derivations, electrooculogram (EOG ) as well as an electrocardiogram (ECG) will be recorded, in order to detect sleep stages and better identify bruxism episodes. The device used in this study has been approved for projects NIH #2R01DE016417-05A1 and #1 R01DE028548-01. 4. Ultrasound for masseter muscle thickness measure 5. Dual-color chewing gum for chewing efficiency measure.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
6
Injections into the masseter muscles bilaterally (25 Units per muscle applied with 2 injections in each muscle)
University of Zurich, Center of Dental Medicine
Zurich, Switzerland
Change of maximum EMG amplitudes
Change of average of maximum EMG amplitudes of all bruxism events per night between days 1-14 (baseline) and days 29-42.
Time frame: days 1-14, days 29-42
Verbal Rating Scale of Global impression of change
Verbal Rating Scale (VRS) containing the following levels "much worse", "slightly worse", "no change", "slightly improved", "much improved" of "global impression of change" at the end of the study (day 154)
Time frame: day 154
Change of maximum EMG amplitude
Change of average of maximum EMG amplitudes of all bruxism events per night between days 1-14 (baseline) and days 15-28, 85-98, and 141-154.
Time frame: days 1-14, days 15-28, days 85-98, days 141-154
EMG amplitude at maximum voluntary contraction
EMG signal amplitude (RMS) at maximum voluntary contraction (MVC) in \[V\]
Time frame: days 1-14, days 15-28, days 85-98, days 141-154
number of masseter contraction episodes per hour (N/h)
number of masseter contraction episodes per hour calculated from EMG signal amplitude normalized on MVC \[N/h\]
Time frame: days 1-14, days 15-28, days 85-98, days 141-154
duration of masseter contraction episodes (Dur)
duration of masseter contraction episodes in \[sec\] calculated from EMG signal amplitude normalized on MVC
Time frame: days 1-14, days 15-28, days 85-98, days 141-154
EMG-Index
EMG-Index = 0.5 x N/h + Dur
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Time frame: days 1-14, days 15-28, days 85-98, days 141-154
EMG Duty Factor
EMG duty factor = % duration of muscle activity/total recording time
Time frame: days 1-14, days 15-28, days 85-98, days 141-154
Sensitivity of masticatory muscles and jaw joints
Sensitivity of masticatory muscles and jaw joints in \[N\]
Time frame: day 1, 14, 28, 42, 98, 154
Self-report of bruxism
Yes/No answer to direct question
Time frame: day 1, 14, 28, 42, 98, 154
Numerical Rating Scale masseter muscle pain
Numerical Rating Scale (NRS) (0-10) with 0 = no pain and 10 = worst imaginable pain
Time frame: day 1, 14, 28, 42, 98, 154
Numerical Rating Scale report of spontaneous facial pain
Numerical Rating Scale (NRS) (0-10) with 0 = no pain and 10 = worst imaginable pain
Time frame: day 1, 14, 28, 42, 98, 154
Numerical Rating Scale report of jaw movement related facial pain
Numerical Rating Scale (NRS) (0- 10) with 0 = no pain and 10 = worst imaginable pain
Time frame: day 1, 14, 28, 42, 98, 154
Numerical Rating Scale report of anxiety over tooth wear
Numerical Rating Scale (NRS) (0-10) with 0 = no anxiety and 10 = worst imaginable anxiety
Time frame: day 1, 14, 28, 42, 98, 154
Numerical Rating Scale disturbed sleep of bed partner
Numerical Rating Scale (NRS) (0-10) with 0 = no disturbed sleep and 10 = worst imaginable sleep
Time frame: day 1, 14, 28, 42, 98, 154