Two-stage crestal sinus elevation by sequential drills in less than 4mm of residual ridge height: a clinical and histologic case report

Resorption and pneumatization of alveolar ridges are common oc- currences in the posterior max- illa after tooth extraction. These may cause not only a quantitative reduction but also a qualitative deterioration of bone leading to a skeletal segment inadequate for implant placement. In these situations, the residual vertical bone height…