We generally associate the term ‘sinus’ with the air-filled cavities behind and on each side of the nose. These are called ‘paranasal sinuses’ of which the maxillary sinuses are the largest. The maxillary sinuses are in close proximity to the upper back teeth. When a sinus becomes inflamed, it is known as ‘sinusitis’. Sinusitis may be perceived as headache and pain in the face, known as sinus pain. Importantly, sinus pain may also be perceived as toothache, even when no dental disease is present. Sinus pain that is unrelated to a tooth usually resolves without intervention or with management of symptoms alone. Sinusitis can be related to a tooth infection, in which case your dentist may consider referral to a dental specialist for assessment and treatment.