There are three main types of CPAP masks: Full face masks, which cover the nose and mouth. Nose masks, which cover the nose only and nasal pillow masks, which insert in to the nose.
All the masks need to provide a firm seal in order to deliver the air pressure through the mask to the back of the throat to keep your airway open in sleep. There any many nuances to mask fitting. It is important to have an experienced CPAP Therapist guide you with mask choice and to have a broad range of masks and brands to choose from.
Nasal pillows are the smallest of all the masks. They have the lowest facial profile and the least facial contact. The prongs insert in to your nose to provide a firm seal with the inside rim of your nose. At times this can cause some nasal irritation. As the mask only seals the nose, mouth leak can occur, which can create airway dryness and nasal congestion. Chin straps may be used to manage mouth leak. Nasal pillow masks may be hard to use if you have nasal obstruction which your doctor can advise you on.