Sinus refers to the cavity in the bone. The sinus you are talking about should be the maxillary sinus, which is one of the four pairs of paranasal sinuses. It is closely related to maxillary posterior teeth. Part of the root of the maxillary posterior teeth is connected with the maxillary sinus, so when dealing with these dental diseases, especially when pulling out the root of these teeth, we must be careful to prevent the root from falling into the maxillary sinus. When the maxillary sinus is inflamed, the corresponding teeth may also have occlusal pain, which should be identified.

Also, there is no mandibular sinus, only maxillary sinus,