The modified trephine/osteotome sinus augmentation technique: technical considerations and discussion of indications.

A technique is presented, which uses trephines of various external diameters followed by an osteotome to implode a core of maxillary posterior alveolar bone before placement of regenerative materials, in anticipation of subsequent implant placement. A mathematical formula is presented, which relates the depth of core displacement to the apico-occlusal dimension of alveolar bone coronal to the floor of the sinus presurgically. Seventy-one sites have been treated. All sites exhibited sufficient regeneration for implant placement. Two of the sites required additional augmentation at the time of implant placement. Fifty-one of the implants have been restored and are in function for up to 3 years. All are functioning successfully, as defined by the Albrektsson criteria. The technique and its indications and contraindications are described in detail.