Sleep Bruxism: The Missing Link

600x300_bruxism_lucoEvery doc treating sleep apnea with oral appliances has come across more than one patient who could destroy their device in a week or two or develop severe jaw pain after a night of use. We all know that sinking feeling when you show up for work Monday morning to see Mr. Jones, disgruntled, standing in front of your door with retainer case in hand!
Sleep bruxism is the third most common sleep disorder, occurring in 8% of adults. Yet it is the least commonly considered when treating sleep apnea. A clarification is needed here. Sleep bruxism is not the same as awake bruxism. WHO2 and the CDC3 both agree on this point. So does the AASM1. Google ‘sleep bruxism’ and you quickly find that most sites refer to both as one in the same – this is an area of great confusion. Sleep bruxism is a sleep disorder, pure and simple, occurring 80% of the time with sleep apnea, synchronizing with each apnea event. It also synchronizes with snoring events in the absence of sleep apnea. The forces generated during sleep bruxism far exceed those generated while awake and are primarily generated by the masseter and temporalis muscles. Sleep bruxism actually is a cascade of physiologic actions:
 

  • There is an increase in heart rate and blood pressure
  • There is an increase in EEG activity (a sleep arousal), Epworth Scores 4 to 9
  • There is an increase in the suprahyoid musculature muscle tone
  • The masseter and temporalis muscles contract in either phasic or repeated movements, tonic or sustained contractions, or mixed, resembling both types, with considerable force
  • Often, the sleep bruxism event concludes with a swallowing reflex1

These events can and do occur hundreds of times each night and can last in excess of 4 to 5 minutes. Although 80% occur with sleep apnea, we cannot overlook the 20% that occur independently. These sleep events together are responsible for most of the dental problems our patients present with. Awake bruxism is not associated with a similar cascade of events1.
As one would expect, the effects of sleep bruxism are far reaching with chipping, breaking, wearing and cracking of the teeth the most common. Signs and symptoms vary widely between patients; there are none that are found in 100% of sleep bruxism cases. The development of painful muscle spasms and myofascial trigger points is common. Growth of maxillary and mandibular exostoses can occur in longstanding sleep bruxism5; teeth under flexing pressure can exhibit painful abfraction lesions. Coronoid elongation (stretching of the coronoid processes) and antigonial notching (bending of the mandible) are seen in chronic cases6. Compression of the TMJ can cause TMD, disk displacements, tearing of ligaments and flattening of the condylar heads (“beaking”)7. Closed locks of the TMJ on waking are very common with sleep bruxism, often lasting for hours1. Posterior capsulitis and lateral TMJ pain are common findings with sleep bruxism. There are no forces generated while awake during normal function that can produce this type of damage to the masticatory system. Single arch bruxism appliances, while protecting the teeth from damage, do nothing to reduce the sleep bruxism events. Or the sleep disruption. Or the increase in heart rate seen with each event.
A typical tracing of sleep bruxism is seen in Figure 1, showing forces so great that the tops of the peaks are clipped or flattened. The lower red box details a heart rate increase from 55 bpm to 97 bpm (tachycardia). When the heart rate exceeds 90, the left ventricle may not fill completely, lowering pumping efficiency.
This increase in heart rate can go as high as 135 bpm in some individuals and can last minutes. The tracing in Figure 1 was on a 19-year-old male referred for severe TMJ pain.
bruxism_luco_fig1aUntil recently there was no treatment available for sleep bruxism. Pharmaceuticals have been studied and, while some showed promise, the side effects were often significant, rendering the treatment unsafe. As sleep bruxism is not psychological in nature, hypnotherapy, psychotherapy, acupuncture and other physical and psychological treatments have all been shown to be ineffective therapy strategies. Botox can reduce the bite force but the clinical benefit wears off; sleep bruxism is a life long illness. There are case studies showing patients who have developed sensitivity to Botox and even some with allergic reactions. The more it is used the higher the risk. Besides, reducing the bite force does not treat the underlying sleep bruxism and its effect on sleep.
In July 2016, the FDA cleared the Luco Hybrid OSA Appliance (Figure 2) for the treatment of sleep bruxism and associated tension/migraine headaches in adults, making it the first FDA cleared treatment for sleep bruxism. A pilot study requested by the FDA demonstrated that this device not only reduced the number and duration of bruxism events, but also reduced the increase in heart rate associated with the events.
bruxism_loco_fig1There were three areas of study: clinical examination, sleep study with EMG recording and visual analog scales confidentially completed by the subjects. 51 subjects were assessed this way, 26 male and 25 female. The results demonstrated clearly that this device not only treated the sleep bruxism, but reduced TMJ, jaw, neck and shoulder pain more than 90%. It also reduced tension/migraine headaches by over 90%. Tooth thermal sensitivity was eliminated. 19 of the subjects had been in treatment for a mean of 4.1 years. The first home study was without the device and the 2nd with. Although they had been in treatment for years, they completely relapsed with only one night of not using the device. The second study demonstrated a complete recovery.
The Luco Hybrid OSA Appliance (Figure 2) has a unique forward bite (US patent D759,824), distributing the bite force evenly through the skull (Figure 3)7. This results in considerable reduction of the damaging effects of sleep bruxism. The only region showing high force is the tip of the cuspid.
When the bite is allowed to contact in the molar regions, there is a very different force distribution (Figure 4)8. In this 3D analysis, high stress regions are seen in the molar, ramus, condyle, TMJ and infra-orbital regions (red areas). This is the cause of TMJ pain associated with many OSA appliances. In fact, the FDA9 list as a risk with the use of mandibular advancement appliances the development of TMJ Dysfunction Syndrome! With the forward bite of the Luco Hybrid OSA Appliance, the risk of TMJ/muscle problems is eliminated.
Of note, these new indications for this device now allow it to be prescribed by a dentist without medical oversight for the treatment of sleep bruxism and associated tension/migraine headaches. The Luco Hybrid OSA Appliance now has the following indications for use (cleared by the FDA) in adults:

MEDICAL (K130797)

  • The treatment of mild to moderate obstructive sleep apnea
  • The treatment of primary snoring

DENTAL (160477)

  • The treatment of sleep bruxism
  • To aid in the treatment of associated tension/migraine type headaches

The Luco Hybrid OSA Appliance is cleared for use in any of these conditions individually or even when they all occur simultaneously. The device requires no modification to existing techniques for the dentist and, with only two points of contact on the forward bite and no acrylic on the lingual, considerably simplifies the insertion process. The Vitallium 2000 framework does not break, reducing costly repairs. With the added benefits of reduced tooth pain, TMJ pain, headache and muscle pain, patients can begin Sleeping in Complete Comfort.
bruxism_luco_fig3-4When treating OSA patients, one cannot underestimate the effects of untreated sleep bruxism. It is present in more than one third of OSA patients and failure to recognize it can lead to disaster. Sleep bruxism is truly the missing link in OSA therapy, and possibly the most significant factor in whether or not the patient will be comfortable (and ultimately compliant) in treatment. And now there is an FDA cleared treatment for OSA patients also suffering from sleep bruxism. It is a long term treatment for TMD/OSA patients that is clinically verified and FDA cleared.
 

luco_headshotDr. Ken Luco graduated in 1986 from the University of Alberta Faculty of Dentistry. He practiced in Cold Lake, Alberta for 2 years before settling in Kingston, Ontario. He has been involved with the treatment of TMD for more than 30 years. He developed the Luco Splint (lower TMD splint). He has been involved in the treatment of OSA for more than 25 years. He developed the Luco Hybrid OSA Appliance over a 14 year period. In 2013, Dr. Luco obtained the first 510K clearance for sleep apnea and snoring. In 2016, he obtained the second 510K clearance for sleep bruxism/associated tension/migraine headaches.

  1. American Academy of Sleep Medicine. International classification of sleep disorders, 3rd ed. Darien, IL: American Academy of Sleep Medicine, 2014.
  2. World Health Organization. (1992). The ICD-10 classification of mental and behavioural disorders: Clinical descriptions and diagnostic guidelines. Geneva: World Health Organization.
  3. “Website Article.” “International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM), Tenth Revision, Clinical Modification, (ICD-10-CM)”, CDC/National Center for Health Statistics, Aug 22, 2016
  4. Serdar Uysal,1 Berna L Çağırankaya,2 and Müjgan Güngör Hatipoğlu3 Do gender and torus mandibularis affect mandibular cortical index? A cross-sectional study, Published online 2007 Oct 30. doi:  10.1186/1746-160X-3-37, Head Face Med. 2007; 3: 37. PMCID: PMC2174449
  5. O C Almăşan,1 M Băciuţ,*,2 M Hedeşiu,3 S Bran,2 H Almăşan,4 and G Băciuţ4 Posteroanterior cephalometric changes in subjects with temporomandibular joint disorders. Dentomaxillofac Radiol. 2013; 42(1): 20120039. doi:  10.1259/dmfr.20120039
  6. ML dos Anjos Pontual1, JSL Freire1, JMN Barbosa2, MAG Frazão2, A dos Anjos Pontual*3, and MM Fonseca da Silveira3 Evaluation of bone changes in the temporomandibular joint using cone beam CT, 2012 The British Institute of Radiology, DOI: http://dx.doi.org/10.1259/dmfr/17815139
  7. Alexandre Rodrigues Freire; Felippe Bevilacqua Prado et al, Biomechanics of the Human Canine Pillar Based on its Geometry Using Finite Element Analysis, Int J Morphol; 21(1):214-220, 2014
  8. Website Article, CV Wroe, Finite Element Model of Human Skull showing stress distribution at 2nd molar, http://compbiomechblog.blogspot.ca/2010/06/blog-post_20.html, June 20, 2010
  9. FDA Document # 1378, Class II Special Controls Guidance Document: Intraoral Devices for Snoring and/or Obstructive Sleep Apnea; Guidance for Industry and FDA

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