Information presented here is to help physicians be able to look at patients “through the eyes of a dentist” to help them more easily suspect the presence of sleep-related breathing disorders in the patients they are examining.

 

RETROGNATHIC MANDIBLE

 

On of the most common predisposing factors contributing to sleep-related breathing disorders is a retrognathic mandible as shown in the photos of the three patients shown below.

 

 

It is obvious that the obese patient on the left with the large neck (any male with a 17″ neck is at risk for obstructive sleep apnea) would be at risk for OSA.  However, the other two patients shown above also have significant sleep apnea.  It is interesting to note that both of their physicians at first refused to send them for a sleep study because “they didn’t fit the mould”.  In other words, they were not overweight. However, looking at the facial profile should have given a significant clue.

 

When in doubt about whether a mandible is retrognathic or not, look at the teeth in full occlusion as in the following photos.

 

 

The above photo shows considerable space between the upper and lower incisors creating a “buck toothed” appearance.  When this occurs, the mandible is always underdeveloped.  This lack of complete skeletal development decreases room for the fully developed tongue.  

 

 

Notice in the above photo with this patient’s teeth closed together how the bottom incisors are not visible.  Again, this is a result of an underdeveloped mandible.  This results in diminished tongue space.

 

 

The above photo shows flared lateral incisors, again, characteristic of an undeveloped mandible.  Patients with retrognathic mandibles (like Featured Patient #103 and Featured Patient #107) tend to do extremely well with oral appliance therapy since moving the mandible forward puts it in a position where it would normally be if it had developed properly during early growth and development.

 

TONGUE SIZE AND POSITION

 

After evaluation of the mandibular position, check the tongue position and overall size.  A tongue that is positioned above the plane of the mandibular teeth as shown in the photo below is more likely to cause an upper airway obstruction than one that is below the plane.

 

 

 

A very large tongue adds to the risk of airway obstruction and will usually have indentations in the edge as shown below.  These indentations result from the large tongue mass pressing against the lower teeth.

 

 

OROPHARYNX AIRWAY SPACE AND SURROUNDING TISSUE

 

Look for a restricted airway space at the level of the oropharynx.  The photo below shows a very crowded airway space.  It takes very little relaxation of the tongue during sleep in a patient like this to cause severe airway obstruction.

 

 

 

Also pay attention to the presence or absence of inflammation in the tissue of the soft palate as shown below.  Tissue does not like to be vibrated.  Tissue vibration from snoring causes inflammation and swelling.  

 

 

Interestingly, this tissue vibration and resulting trauma to the palatal tissues has been shown to result in neurogenic lesions in the palatopharyngeal muscle, one of the dilator muscles that opens the airway.  Over time, this trauma lessens the ability of this muscle to function.