Can maxiliary sinusitis lead to tooth infection?

Rarely: Usually it is the other way around. The dental abscess erodes into the sinus. Sinusitis can definitely cause tooth pain As the nerves for your upper teeth run along the floor of the sinus and the pressure and inflammation from the sinus irritate the nerves. If your are having severe tooth pain have your dentist check to make sure there is not a dental problem contributing to your sinus problem.

Highly unlikely: A tooth infection is caused by a nerve in the tooth that has become non-vital, and/or a very large cavity that has extended into the pulp chamber that is allowing bacteria to enter the bone through the tooth. Sinusitis (inflammation of the sinus) would not do that.

The opposite is true: It is certainly possible that an infected tooth, usually the first maxillary molar, can cause a sinusitis. The sinusitis, is an inflammation of the sinuses and nasal passages. It does not lead to tooth infection. Both infections are treatable with a predictable positive outcome. Hope it helps.