Plain English Summary
Background and study aims
Sleep bruxism is the medical term for grinding the teeth and clenching the jaw during sleep. It is associated with a number of clinical problems, including pain, tooth wear and failure of dental restorations. Some of these patients require orthodontic treatment. The use of clear aligners ("invisible braces") has increased in orthodontic practice. They are comparable to occlusal splints, plastic appliances that fit onto the teeth which are routinely used in patients suffering from sleep bruxism to prevent tooth wear. The aim of this study is to find out whether clear aligners can be used to treat sleep bruxism.
Who can partecipate?
Adolescents (aged from 16 years) and adults (>18 years) requiring orthodontic treatment and suffering from sleep bruxism
What does the study involve?
Participants are randomly allocated to one of two groups. Participants in the first group are treated using orthodontic clear aligners. Participants in the second group are treated using a palatal splint with no tooth coverage. For participants in both groups,, sleep bruxism activity is recorded at home in the night at the start of the study and then after 1, 3, 6 and 12 months.
What are the possible benefits and risks of participating?
Participants may be protected against the effects of sleep bruxism (i.e. toothwear, dental fractures, dental sensitivity). There are no risks expected for those taking part in the study.
Where is the study run from?
University of Torino (Italy)
When is the study starting and how long is espected to run for?
May 2014 to February 2017
Who is funding the study?
University of Torino (Italy)
Who is the main contact?
Dr Andrea Deregibus
Effects on sleep bruxism activity of orthodontic clear aligners detected with nocturnal instrumental ECG/EMG recording: a randomized clinical trial
The aim of this study is to find out if sleep bruxism activity is influenced by the use of clear aligners.
Ethical Committee A.O.U Città della Salute e Della Scienza di Torino, 15/09/2016, ref: 0089211
Single-centre randomized interventional trial
Primary study design
Secondary study design
Randomised controlled trial
Patient information sheet
No participant information sheet available
A group of 40 patients will be screened for sleep bruxism with a validated portable device (Bruxoff®, OT Bioelettronica, Torino, Italia) before being randomly allocated (random number list software generated) into two different treatment groups.
Group 1: aligner group (AG) with 20 subjects who will be treated with orthodontic clear aligners (Invisalign®, Santa Clara, CA)
Group 2: placebo group (PG) with 20 subjects who will be treated with palatal splint with no tooth coverage
Both groups will be treated at the Department of Orthodontics of the Dental School of the University of Torino.
Both groups will be recorded with multiple nocturnal instrumental ECG/EMG recordings in order to screen and control possible variation in sleep bruxism activity. The ECG/EMG recording will be conducted with a three channels validate portable device for sleep bruxism diagnosis (Bruxoff ®, OT Bioelettronica, Torino, Italy). Two channels will be used to acquire surface electromyography (sEMG) bilaterally from the masseter, and the third channel will be used to acquire the electrocardiographic activity (ECG). The three signals will be sampled at 800 Hz, with 8 bit resolution. The data will be stored on a MicroSD card as a binary file. The sEMG channels will be filtered between 10 and 400 Hz with gain 4300. The electrocardiographic (ECG) channel will be filtered between 15 and 160 Hz with gain 700. Surface EMGs from the masseter muscle of both sides will be detected with disposable bipolar concentric electrodes (Code®, Spes Medica, Battipaglia, Italy), with a radius of 16 mm and with detection site made of AgCl. The heart frequency will be detected with a disposable bipolar electrode located on the left side of the thorax just below the pectoral muscles. At the beginning of the recording, the subjects will be asked to perform three maximum voluntary clenching (MVC) lasting 3 s each and separated by 10 s of rest. The greatest of the MVC measures will be used for normalizing the EMG values as a percent of MVC. Scoring on the Bruxoff recordings will be automatically performed by dedicated software (Bruxmeter ®, OT Biolettonica, Torino, Italy). The software is able to classify a SB episode if the sEMG burst is greater than 10% MVC and if it immediately follows (1-5 seconds interval) a heart rate increase of 20% with respect to the baseline. Moreover, instrumental evaluation allows to identify specific sEMG signals: tonic, phasic and mixed. The subjects will use the device and mount the electrodes at their homes without technical assistance, after prior training. They will be provided with written instructions and a night-time telephone number to call in the event of difficulties.
For participants in both groups, at baseline and then after 1, 3, 6 and 12 months, nocturnal instrumental recordings of ECG/EMG activity will be recorded in home setting to detect variations in sleep bruxism activity.
Primary outcome measure
Sleep bruxism index, determined from Bruxmeter software at baseline, 1 month, 3 months, 6 months, and 1 year
Secondary outcome measures
EMG signals (tonic, phasic or mixed), measured with dedicated software at screening, 1, 3 and 6 months, and 1 year
Overall trial start date
Overall trial end date
Reason abandoned (if study stopped)
Participant inclusion criteria
1. Patients able to give their informed consent
2. Patients suffering from sleep bruxism
3. Good oral hygiene and periodontal status
4. Patients requiring orthodontic treatment
5. Adolescents (aged from 16 years) and adults (>18 years)
Target number of participants
Participant exclusion criteria
1. Patients suffering from neurological diseases
2. Patients suffering from signs/symptoms of tempormandibular disorders
3. Patients already wearing occlusal splints
4. Patients with orthodontic treatment in progress
5. Post traumatic patients
6. Patients suffering from other sleep disorders (i.e., sleep apnea, restless leg syndrome)
Recruitment start date
Recruitment end date
Countries of recruitment
Trial participating centre
Dental School, Department of Orthodontics
University of Torino Via Nizza 230
Università degli Studi di Torino
University of Turin, UNITO
Funding Body Type
Funding Body Subtype
Results and Publications
Publication and dissemination plan
Planned publication in a high-impact peer reviewed journal in 2018
IPD sharing plan
The datasets generated during and/or analysed during the current study are/will be available upon request from Prof. Andrea Deregibus
Intention to publish date
Participant level data
Available on request
Basic results (scientific)