Replacing a Single Posterior Crown in One Appointment

Figure 1: The patient’s chief concern was an open mesial margin of the crown on tooth #15, which was causing gingival inflammation and shredding her dental floss.

Figure 2: The crown was a 20-year-old Captek^™ PFG high-noble bilayered restoration.

Figure 5: There were some recurrent caries on the mesial of #15 where the margin was open.

Figure 6: After refinement of the tooth preparation, the margin was ex­posed using the two-cord technique. For apical compression, I used Premier’s Knit-Pak^™ #00 as the first cord. For lateral deflection of the tissue, I placed a #2 cord presoaked in Hemodent^® hemostatic liquid over the first cord. The patient bit down on Roeko Comprecap compres­sion caps (Coltène/Whaledent GmbH + Co KG; Langenau, Germany) for five minutes for continued compression. The second cord was gently removed to expose the margin, allowing for a high-quality digital scan.

Figure 7: Clinical evaluation of the occlusal reduction ensured there was adequate space for the restorative material. For BruxZir Esthetic NOW Posterior, the minimum required thickness is 0.7 mm. I typical­ly remove around 2 mm for the occlusal and 1 mm for axial reduction. I also made sure that there were at least two or three plane reductions and all transitions were smooth and rounded for ideal milling of the chair­side CAD/CAM crown.

Figure 8: The final scan shows well-exposed margins. I used the Medit^® i900^® scanner, which pairs seamlessly with the fastdesign.io^™ system. With just a click, the scan was sent to the fastdesign.io software.

Figure 9: The MarginAI^™ software, which is part of the fastdesign.io software suite, detected most of the margin, which I rechecked and confirmed.

Figure 10: With a click of the mouse, CrownAI^™ generated a design to fit the space. I rechecked my preferred contact parameters.

Figure 11: Before sending the design to the mill, it’s important to use the milling and insertion tool to verify that the restoration has an ade­quate path of insertion. A green line indicates it is okay to proceed, while a red line signals an issue. I completed the design in under five minutes and sent it to the fastmill.io^™ In-Office Mill for fabrication.

Figure 13: Before final seating, I like to use try-in paste and take a bite­wing radiograph to verify the fit.

Figure 14: This image shows the final delivery of the BruxZir Esthetic NOW Posterior crown #15. I used BruxZir^™ Dual Cure Resin Cement (Glidewell Direct; Irvine, Calif.), which is a self-adhesive translucent white shade, ideal for zirconia crowns.