Don't know... The mandible is the jaw, and there is no sinus in the jaw. Are you sure you don't mean right maxillary sinus disease? If so, that means the sinus (air-filled space) beneath your cheek bone above your upper teeth. As far as the 'disease' part, the most common thing is inflammation, or sinusitis, which can cause stuffy nose, pain/pressure feeling, +/- infection. Ask your md for clarification.