Upper right premolars #14 & #15 with the Crown Down 2-drill protocol

Photo essay

The surgical sequence, step by step

Every step below shows Dr. Miselli's original clinical imagery paired with a short technical note on what the Crown Down protocol is doing at that moment.

1. STEP 01

   Planning from CBCT

   Two adjacent maxillary premolar sites were planned from CBCT with two implants: 3.75 x 11.5 mm at #14 and 3.75 x 10.0 mm at #15. The panoramic reconstruction and 3D model at the left confirm axial angulation and inter-implant spacing; the two right-hand sagittal slices show adequate bone volume at both sites with respect for the buccal plate.

   

2. STEP 02

   First drill - cortical only

   The Crown Down first drill is a solid tungsten carbide cortical drill matched to the target implant diameter. In this case it engages only the cortical plate, breaching the crest to the depth of the cortical layer and no further. Selectively reducing cortical interference first is the mechanical premise of the protocol: it prevents the crestal ring from dominating the eventual torque signature.

   

   

   

3. STEP 03

   Second drill - trabecular Ø 4 mm

   The second drill in the sequence extends the osteotomy through the medullary compartment at approximately 8 mm of depth. Because the cortical layer has already been dedicated its own pass, the second drill only engages trabecular bone - which behaves differently mechanically and preserves a wider tactile window on the handpiece.

   

   

4. STEP 04

   Third drill - Ø 3 mm bone collection at 50-80 rpm

   A dedicated 3 mm drill is run slowly, at biologic speed (50-80 rpm), through the prepared site. Because Crown Down drills at low speed without continuous external irrigation, the bone particles produced during this pass stay in the site and on the flutes rather than being washed into the suction line. Those chips can be collected chairside and used as an autogenous graft in the same appointment.

   

   

5. STEP 05

   Osteotomy check and depth confirmation

   Before switching from drilling to implant placement, the site is inspected and the depth is confirmed with a graduated probe. The reference shown here is 11.5 mm + 2 mm, which corresponds to the planned depth for the #14 implant plus a small safety margin.

   

   

6. STEP 06

   Implant #14 - 3.75 x 11.5 mm

   The first implant is seated at the mesial site. Because the cortical ring has been decompressed by the initial cortical drill, the torque wrench reading during placement reflects primarily the medullary bone's contribution rather than crestal compression against a bone-tap-like preparation.

   

   

7. STEP 07

   Implant #15 - 3.75 x 10.0 mm

   The distal site receives a slightly shorter implant of the same diameter. Both implants are placed in the same visit and prepared with the identical 3-drill sequence, so the surgical rhythm and tactile feedback remain consistent between adjacent sites.

   

   

8. STEP 08

   Both implants seated, cover screws in place

   Occlusal view of the completed placement: two adjacent implants at #14 and #15 with cover screws, ready for closure. From here the case is followed with a post-operative periapical radiograph before releasing the tissue.

   

9. STEP 09

   Post-operative periapical radiograph

   Post-op periapical radiograph confirming both implants at planned depth and axial angulation, respecting the adjacent tooth roots and the sinus floor.

   

Case questions and technique reference

Quick clinical answers dentists ask about this case and about the Crown Down 2-drill protocol it demonstrates.