Discuss in brief about maxillary sinus
In normal conditions, the maxillary sinus maintains a close relationship with the alveolar ridge associated with second premolar and first molar teeth.
With age the sinus floor expands and is often in close relationship with the apices of the posterior teeth separated from the sinus mucosa by a thin layer of bone but occasionally may be in direct contact with mucosa. Loss of teeth causes the antrum to further expand, so that the sinus floor ultimately joins the crest of the ridge. This position of the sinus floor affects the implant placement, in that sinus lift procedure is necessary so that the implants can be placed without perforating the sinus floor.