http://virginiasurgicalarts.com/services/oral-surgical-procedures/bone-grafting/ Sinuses are air-filled spaces or cavities behind our cheekbones. The maxillary sinuses are behind your cheeks and on top of the upper teeth. The roots of the upper molars extend up into the maxillary sinuses. When these upper teeth are removed, there is often just a thin wall of bone separating the maxillary sinus and the mouth. Dental implants need bone to hold them in place. When the sinus wall is very thin, it is impossible to place dental implants in this bone.
