Early on we discussed tooth grinding at night and looked at the repercussions: These ranged from tooth wear, muscle fatigue, pain in the temporomandibular joints (TMJ) to headaches and neck pain.
Grinding your teeth is when you apply forces to them which cause them to gnaw and gnash against one another. It is now believed that the action of clamping your teeth together and grinding back and forth may be a physiologic response to counteracting the effects that occur when our airways are obstructed: Obstructive Sleep Apnea (OSA)…….Let’s go back.
The Tongue and Associated Structures Fall Back:
In the blog “Sleep Apnea…What is it and how does it relate to dentistry?” posted on July 22nd 2013, we found that during sleep (especially on our backs), the tongue and related soft tissue fall to the back of our throats
1. While asleep, muscle tone changes and the muscles in our throats relax…this and gravity too, is why they fall back. The mandible (jaw bone which houses the lower teeth) also tends to fall back. This is because the jaw has many muscles attached to it (the tongue being quite large and significant). So if the muscles relax and fall back, then the jaw will follow it.
2. The problem is further compounded: To deal with the lack of air due to the obstruction, the chest expands and this creates an even greater intra thoracic pressure. This negative pressure tends to increase the ‘pull’ on the upper airway soft tissues even more.
Note: If an individual has a small jaw, then this adds to the obstruction as the tongue is now more crowded out (there is less room to ‘house’ it).
The Reason for the Clenching and Grinding
To counteract the effect of the tongue and associated soft tissues falling to the back of the throat, the individual will naturally compensate for this by clenching and grinding their teeth together: this tends to bring the lower jaw forward…you can look at it this as a compensatory action to deal with the soft tissue obstruction.
The Role of Continuous Positive Airway Pressure (CPAP)
Forced air (air under pressure) will open up the airway and override the obstruction.
It has been shown that treatment with CPAP has led to the cessation of nocturnal bruxism in many of the affected individuals.
The Role of Mandibular Advancing Devices (MAD’S)
It may be best to refresh your knowledge of MAD’s by reading the blog “Let’s look at the different ways to open up the airway and prevent snoring” posted on July 29th, 2013. The concept is quite simple: The appliance advances the lower jaw (mandible) forwards which brings with it the tongue and associated soft tissues. This reduces the obstruction at the back of the throat by opening up the airway. This in turn helps to relieve the nocturnal bruxism.
Mad’s are indicated for the treatment of snoring and mild to moderate sleep apnea…have a nice week everyone!
Dr. F. Keshavarz Dentistry