TABLE 2.

Characteristics of responders and nonresponders to oral appliance therapy

Characteristics	Responders	Nonresponders
Clinical	Younger individuals [69, 70] Lower BMI [49, 69, 70] Shorter neck circumference [49, 69, 70] Sex – female [69, 70] Lower prevalence of cardiovascular disease [74]	Older individuals [69, 70] Higher BMI [49, 69, 70] Larger neck circumference [49, 69, 70] Sex – male [69, 70] Increased cardiovascular burden [74]
Anatomical	Retracted maxilla or mandible [49, 69, 70] Lower anterior and posterior facial height [69] Shorter distance from the hyoid bone to the third cervical vertebrae [69] Shorter airway length [69] Forward movement of the tongue [72, 73]	Nasal abnormalities [69] Minimal movement of tongue [72, 73]
Polysomnographic parameters	Low loop gain [75] Low AHI [75] Higher arousal threshold [75]	Low oxygen desaturations [75]

AHI: apnoea–hypopnoea index; BMI: body mass index.