The overall objective of the current study is to improve upper airway collapsibility and sleep apnea in OSA patients who have a high percentage of mouth breathing during sleep. The investigators' central hypothesis is that preventing the lips from parting with the Varnum device will reduce oral breathing and thereby OSA severity in mouth breathers. The investigators chose this hypothesis because "taping the mouth closed" with a simple device such as the Varnum mouthpiece is the most straightforward approach to dealing with this common problem. With this research, it could become possible to overcome one of the major problems contributing to sleep apnea - mouth breathing.