Does maxillary sinusitis mean there is a tooth infection?

Maxillary infection: No, not necessarily. Deep root infections of the upper teeth can lead to maxillary sinus infection, but not always. More likely your maxillary sinusitis evolved from inadequate sinus clearance of mucus and associated bacteria.

No: An infected tooth is a whole different kettle of fish. The maxillary sinuses are in your cheek areas, above /behind the teeth. That's not to say a severe dental infection couldn't get up into the maxillary sinuses - it can. But you can have perfectly healthy teeth and develop a maxillary sinus infection. This is particularly true for those of us who have seasonal allergies and it's ragweed season!

No: Sinusitis is inflammation of the sinus, and is not necessarily caused by a tooth infection.

No, sinus infection: also called sinusitis, is an inflammation of the sinuses and nasal passages. It is certainly possible that an infected tooth, usually the first maxillary molar, can cause a sinusitis. Both infections are treatable with a predictable positive outcome. Hope it helps.