Everyone has a sinus on each side of their nose called the maxillary sinus. Wherein, the roots of the upper back teeth go into the right and left maxillary sinuses. This can cause a problem during sinus season. If a sinus has an infection, it can fill up with fluid and cause the entire sinus lining to become inflamed. If encountered by patients they will feel pain in their upper back teeth along with a metallic taste in the mouth. Threatening a major dental problem if continuously endure.