The debate about centric relation

In the previous article, I shared my observation of several patients wearing deep notches or grooves into well-adjusted occlusal appliances. The appliances were fabricated in the most fully-seated-condylar-position achievable on the day of records. All of the appliances were subsequently adjusted throughout several appointments to confirm the primary guidelines for "successful occlusal therapy," as suggested and widely-accepted by Dr. Pete Dawson1 and Dr. Frank Spear for decades. Although centric relation position was ideal for these appliances, it seemed that there was a distinct possibility that they might be aggravating an underlying condition of sleep apnea – that I was suffocating my patients! In this article, I want to address the ambiguity surrounding this dilemma and discuss some steps that we can all take to see through some of it and help our patients make healthy choices.

We fabricate, insert and adjust occlusal orthotic appliances every day for people that experience nighttime bruxism – mostly to protect their teeth. There doesn’t seem to be any ambiguity or fault in that, right? 

Well, in one pilot study by Mayer, Rompre, and Lavigne, the Apnea Hypopnea Index (AHI), which is the average number of apneas plus hypopneas per hour of sleep, was increased by more than 50 percent in five of the 10 patients. This was from baseline (no splint) to splint nights, and the percentage of sleeping time with snoring also increased by 40 percent with the splint.2 The study concluded that the use of an occlusal splint “is associated with the risk of aggravation of respiratory disturbances” and that it may be relevant for clinicians to question patients about snoring and sleep apnea when recommending an occlusal splint.  Does this mean that every single time that we think about putting a piece of protective, pain-reducing, or diagnostic plastic in our patient’s mouths that we need to ask them about sleep? What do we ask? What do we do with the answers? What if they don’t fit the profile?

What Are the Options?

There are several avenues to question our patients about sleep.

  1. Add a few intentional questions into your medical/dental history.  A small section titled “TMJ and Sleep” will not only stimulate some curiosity for all of your patients before a formal conversation about it, but it will also immediately demonstrate that your practice is different from most. A sample is attached here.

  2. Ask all new patients and/or all patients for whom you are considering appliance therapy to complete an Epworth Sleepiness Scale, attached here.

  3. If appropriate, is to have your patient’s bed partner complete the Bed Partner Survey, attached here. This can be one of the most beneficial and impactful ways for you and the patient to evaluate current concerns and experiences. Most bed partners that hear breathing issues, snoring, or witness daytime sleepiness are relieved that someone else is on their side.

  4. Finally, a short assessment routinely used is the STOP-BANG Assessment, attached here, which incorporates some of the stereotypical risk factors. Implementing any or all of these simple changes in your new patient experience will help alleviate the need to backtrack when you are recommending an appliance and help you identify whether sleep is a contributing factor. Moreover, it is another tool in your practice to help your patients make health decisions. 

You can also see this article for more about speaking to your patients about sleep disorders.

What If the Patient Doesn't Seem to Fit the Profile for Sleep Apnea?

Why should you even ask about this if the patient doesn't seem to exhibit the warning signs of sleep apnea? A 2008 study at Stanford noted that several subjects “did not fit the typical profile for patients with sleep disorder breathing, in that they were not obese, they did not experience significant snoring,” and “complaints of fatigue and difficulty falling asleep were not those of the ‘prototypical’ sleep apnea patient with excessive daytime sleepiness.”3 It would have been so simple to rule out anyone who does not have a BMI of more than 35 kg/m2, or does not have a neck circumference larger than 40 cm or who is not aware of snoring, right? 

As with almost everything else in dentistry, and healthcare as a whole, making assumptions based on generalizations can result in missed diagnoses and progression of disease. We use our dental specialists with great predictability and incorporate them into the systems within out practice. We refer out and manage the overall treatment. Sleep and the effects it has on our teeth are no different.

In the next article, I will demonstrate a predicable flow for all patients for whom you are considering splint therapy with questionable sleep history and describe how we can still protect their teeth while guiding them to health. In the meantime, I hope you will consider the evolution to routinely questioning patients about sleep, making it part of the foundation for your comprehensive, health-centered practice.

(Click the link for more articles by Dr. Kevin Kwiecien. You can also check out this SpearTALK thread to see more finding centric.)


  1. Dawson, P., Functional Occlusion:  From TMJ to Smile Design, p. 31, Mosby Inc., 2007
  2. Int J Prosthodont. 2004 Jul-Aug;17(4):447-53. Aggravation of respiratory disturbances by the use of an occlusal splint in apneic patients: a pilot study. Gagnon Y, Mayer P, Morisson F, Rompré PH, Lavigne GJ.
  3. Prospective Randomized Study of Patients with Insomnia and Mild Sleep Disordered Breathing, Guilleminault C; Davis K; Huynh N, Stanford University Sleep Medicine Program, Stanford, CA, SLEEP, Vol.31, No. 11, 2008, 1527-33