Applying Digital Dentistry to an Esthetic Restorative Case

As today's patients become more informed, discerning, and demanding, ever greater pressure is being placed on the dental team to meet their restorative objectives. Fortunately, digital dentistry has emerged to provide tools that not only reduce the subjective human element in the communication process and people-driven workflows, but that also empower the patient in the critical esthetic decision-making process. From intraoral scanners and CAD/CAM production to powerful software that allows the patient to preview and approve the proposed final case outcome, the digital approach to the information exchange, workflow, and final outcome offers the patient, dentist, and laboratory a more predictable, accurate, and efficient pathway to meet their envisioned expectations.

A healthy female in her mid-20s presented to the practice concerned about the shade and shape of a crown that had been placed 10 years earlier on tooth No. 8, the cervical contours of tooth No. 9, and white discolorations on teeth Nos. 6, 7, 10, and 11, which made her self-conscious about her smile (Figure 1 and Figure 2). She was studying for her law bar exam, and before venturing into the workplace, she wanted to improve the esthetics of her smile. At the consultation appointment, the clinician also noted the cervical concavities causing a black triangle between teeth Nos. 8 and 9, as well as the gingival height discrepancy between the teeth. Tooth No. 9 also exhibited a chip on the incisal edge. Although the patient wanted to restore all six teeth, the clinician advised that the white spots noted on the four teeth could be treated without destroying any tooth structure and recommended restorations for teeth Nos. 8 and 9, along with crown lengthening for tooth No. 8. The patient agreed and was scheduled for a records-taking appointment.

Restoring single centrals that blend seamlessly with adjacent teeth while taking into consideration lip dynamics is one of the most difficult challenges in dentistry and requires the dentist and laboratory to have a shared vision for the final case outcome. At the next appointment, x-rays were taken, along with a series of photographs, following the protocol set by the laboratory for highly esthetic cases. The upper arch was scanned using an intraoral scanner (iTero, Align Technologies), capturing the length and width of the natural teeth and the occlusal surfaces of both arches for communication with the laboratory. The intraoral scans and the series of photographs were uploaded to the laboratory for a case design proposal. An online TeamViewer meeting was scheduled for the dentist and technician to discuss the case and view the proposed shared vision of the case design.

Virtual Case Design Communication Protocol

Prior to the TeamViewer meeting, the laboratory technician imported the straight-on 2D full-face digital photograph of the patient and the 3D intraoral scan into CAD software (3Shape Dental System, 3Shape), aligning them to create the perfect midline and incisal edge position for generating a design of the case (Figure 3).

The virtual case design was shared with the dentist for 3D analysis (Figure 4), including virtual simulation of chewing motions, a cross-sectional analysis of the proposed design for determination of final material thickness and preparation design, and the inclusion of a wing-tipped pontic at the gingival interface to close the black triangle between teeth Nos. 8 and 9. Once the design had been approved by the dentist, the digital case design file was shared via video conference with the patient for her input and approval.

With approval from the patient, the laboratory 3D printed a model with tooth surface texture of the designed teeth Nos. 8 and 9 and created a silicone putty matrix to send to the dentist for preparing the teeth and fabricating temporary restorations to precisely replicate the approved design of the crowns for teeth Nos. 8 and 9.

Preparation, Temporization and Final Delivery

At the preparation appointment, teeth Nos. 8 and 9 were prepared for crowns, an infiltration agent (Icon Resin Infiltration, DMG America) was applied and light cured to remove the white spots on teeth Nos. 6, 7, 10, and 11, and crown lengthening of tooth No. 8 completed. A photo was taken with shade tabs next to the natural teeth to ensure the final restorations would blend seamlessly with adjacent dentition, as well as to communicate the darker preparation shade of tooth No. 8, which would impact restorative material selection for the case (Figure 5). The photo of the preparations with shade tabs was uploaded to the laboratory for restorative material consideration and fabrication. The dentist used the laboratory-fabricated silicone putty matrix to create provisional restorations (Luxatemp, DMG America). Multiple photos and an intraoral scan of the patient with seated temporaries were uploaded to the laboratory for finalizing the design and fabricating the final restorations.

Because of the darker preparation shade of tooth No. 8 and the high translucency on the incisal edge of the patient's natural teeth, it was important that the final crowns were fabricated with a zirconia material that was highly esthetic yet would mimic translucency on the incisal edges and blend seamlessly with the natural teeth once seated (IPS e.max ZirCAD Prime Esthetic, Ivoclar Group).

The final full-contour restorations were milled (ProgaMill PM7, Ivoclar Group) (Figure 6 and Figure 7). Prior to sintering, the surface anatomy of the restorations was finalized and internal stains (IPS e.max ZirCAD Coloring Liquid, Ivoclar Group) added to further mimic incisal translucency (Figure 8). Once sintered, the final crowns were stain and glazed (IPS Ivocolor, Ivoclar Group), final fired, and delivered to the practice (Figure 9 and Figure 10).

Final Restorations and Seating

The patient returned to the practice for the seating appointment. The clinician removed the temporaries and air abraded the preparations (PrepStart, Danville Materials) to remove any remaining particles of cement or debris prior to try-in of the final restorations. The preparations were rinsed and dried, and the crowns tried in using a water-soluble try-in paste (Variolink Esthetic Neutral, Ivoclar Group) for patient approval of the final restorations. The esthetics of the restorations were analyzed by the patient and dentist in natural light for final approval. For final cementation, a rubber dam was clamped in place (Nic Tone, MDC Dental) for moisture control and to ensure complete isolation (Figure 11). Each crown was rinsed, and a cleaning agent (Ivoclean, Ivoclar Group) applied into each restoration for 20 seconds, rinsed, and dried. A primer was applied to each preparation (Monobond Plus, Ivoclar Group), and a cement applied to each crown (IPS e.max ZirCAD, Ivoclar Group), the crowns seated and light cured. The patient was thrilled with her new smile (Figures 12 through 15) and returned 2 weeks later for a follow-up appointment to check the bite, assess healing of the gingival architecture, and confirm appropriate occlusal function.

Digital workflow in dentistry enhances the communication pathway for the patient, dentist, and laboratory to deliver prosthetic solutions that are highly esthetic and more accurate and predictable in order to meet increasing patient demands and expectations.

Julie Driscoll, DMD
Private Practice
Charleston, South Carolina

Mike Roberts
CMR Ceramist
CMR Dental Laboratory
Idaho Falls, Idaho