The maxillary sinus continues to grow until eruption of the permanent teeth (4). The adult sinus is variable in its extension, in one-half of cases extending into the alveolar process forming an alveolar recess. In these instances the sinus comes in close proximity to the roots of the maxillary posterior teeth. With the loss of posterior teeth, the sinus can extend further into the alveolar bone, even reaching the alveolar ridge occasionally (4). The roof of the maxillary sinus forms the floor of the orbit and is a thin bone wall with the infra- orbital neurovascular bundle in its centre. The.
