[The influence of the relationship between the root apex of the posterior teeth and the maxillary sinus floor on the thickness of the maxillary sinus mucosa].

The most common relationship between the posterior maxillary tooth apex and the maxillary sinus floor is Class Ⅱ. The palatal root of the first molar is most closely related to the maxillary sinus floor, the mesiobuccal root of the second molar ranks second. The thickness of the maxillary sinus mucosa varies on the relationship between the different maxillary posterior teeth apex and the maxillary sinus floor. The average thickness of the maxillary sinus mucosa in Class Ⅲ is thicker than Class Ⅱ and Class I. In Class Ⅲ, as the distance from the apices to the maxillary sinus floor increases, the thickness of maxillary sinus mucosa increases.