Cover an Implant with Vital Bone using Trephine Bur
Fig.1 shows the sagittal section of the upper right posterior quadrant (3: #3 palatal root, 2: edentulous area to receive implant; S: sinus). The bone height is 5.8 mm. If the trephine bur with 4 mm outer diameter) does not engage into the bone easily, a 2.0 mm pilot drill is used to create initial osteotomy short of sinus floor (~4 mm deep). Osteotomy is increased by sequentially using 2.5, 3.0, 3.5 and 4.0 mm reamers (Fig.3). Bone shaving is saved. The last 1-2 mm of osteotomy (i.e., sinus floor) is prepared using 4 mm trephine bur (Fig.4 red lines). A flat end osteotome (4 mm in diameter, Bicon comprehensive kit) or tap is used to push the sinus floor upward gently and slowly (Fig.5 arrow). Use a small curet to separate the sinus membrane off the sinus floor lateral to the osteotomy. Put the saved autogenous bone graft back to the osteotomy. Push it upward with Bicon bone condenser. When an implant is placed (Fig.6 pink outline, e.g., 6x11 mm), the top is covered by the vital bone, whereas the side by the harvested bone (*, although the latter loses direct blood supply).
Assistants Sinus Lift
Xin Wei, DDS, PhD, MS 1st edition 09/29/2013, last revision 01/08/2014