Versatile CAD/CAM Digital Impression Technology

CASE REPORT 1
Diagnosis and Treatment Plan
David, a mid-30s male, presented to our office as an emergency patient for a limited exam. His chief complaint was cold sensitivity with lingering throbbing, and a “broken piece of tooth” in the upper right area. He was interested in saving the teeth and wanted to get back on a regular dental schedule. However, due to his hectic work schedule, time was a major consideration.

Limited radiographic (Figure 1) and clinical examination revealed decay into/near the pulp on tooth No. 3 extending subgingivally, and failing amalgam restorations in teeth Nos. 2 and 4 with poor broken down margins (Figure 2).

The limited treatment plan focused on addressing the chief complaint: pain in the upper right area. The patient opted for complete endodontic therapy, a full-coverage restoration on tooth No. 3, and direct composite resin restorations for teeth Nos. 2 and 4. This would be accomplished in a single visit due to his hectic work schedule. The patient was given a prescription for PenVK antibiotic and provided a small deposit to reserve his 2.5-hour appointment a few days later.

When completing multiple teeth in a single visit, whether direct or indirect, it is important to create a “plan of attack” to maximize efficiency. In order to give complete access to finish and polish the interproximal contacts, it was determined to complete the direct restorations first. The crown would then be prepared and fabricated chairside utilizing the CEREC Bluecam, and during the milling process, endodontic treatment would be completed. The final glazed (in-office) restoration would then be delivered.

CLINICAL TREATMENT PROCEDURES
The patient was given anesthetic infiltration (Septocaine [Septodont]) to achieve profound anesthesia, and the upper right quadrant was isolated using the Isolite system (Isolite Systems) (Figure 3). The failing amalgam restorations and recurrent caries were removed and the preparations were finalized for Class II direct composite resin restorations. To assist in forming interproximal contacts and proper contours, V-Rings (Triodent) and wedges were placed on both teeth simultaneously (Figure 4). The direct composite resin restorations (Gradia Direct [GC America]) were finalized using an incremental placement technique (Figure 5). Full attention could now be given to tooth No. 3.

To ensure a uniform and proper occlusal reduction, a 2.0 mm depth reduction bur (Occlusal Router [Meisenger]) was utilized for all-ceramic crown preps (Figure 6). After interproximal reduction was completed (856-016 Coarse [Microcopy Disposable]), a diamond-polishing disc (Super-Snap Disc [Shofu]) was used to smooth any imperfections in the adjacent restorations (Figure 7). At this point, the rough crown preparation was completed with a 856-016 Coarse, and the tooth was inspected for residual decay with caries detecting dye (Seek [Ultradent Products]) (Figure 8). Removal of dye-stained dentin led to pulpal exposure as was predicted based upon evidence found in the radiographic examination. The preparation was finalized with a fine grit diamond bur (856-021 Fine [Microcopy Disposable]) and tissue retraction was accomplished using dental cord (Ultrapak [Ultradent Products]) to allow full visualization of margins.

Once the preparation was completed (Figure 9), the digital impression images were captured quickly and efficiently intraorally with CEREC Bluecam. The restoration was designed chairside and the IPS Empress CAD block (Ivoclar Vivadent) was sent to the in-office CEREC MCXL milling unit for fabrication.

During the milling process, the upper right was isolated with a rubber dam and straight line access was created. Using magnification provided by a dental microscope (Global G6 [Global Surgical]), 4 canals were located and shaped with rotary nickel titanium instrumentation (GT Series X [DENTSPLY Tulsa Dental]) (Figure 10). At this time the milled restoration was retrieved and tried in the mouth to verify marginal integrity. To maximize efficiency, the milled restoration (Empress) was stained and glazed; while all 4 canals were soaked, cleansed, and obturation completed (Figure 11). The buildup and final restoration delivery were completed in a single step utilizing resin buildup/cement (Anchor [Apex Dental]) (Figures 12 and 13).

The technique, as described above, resulted in a single, efficient appointment that provided the patient with an excellent and highly aesthetic outcome (Figure 14). This addressed his chief complaint and built confidence in our practice.

CASE REPORT No. 2
Diagnosis and Treatment Plan
Gerald, a mid-40s male, came into our office for his hygiene recare appointment. This occurred about 12 months after completing endodontic treatment on his mandibular right first molar (tooth No. 30) at the specialist’s office. Typical of this scenario, the temporary restoration was now well beyond the intended lifespan and the tooth had recurrent caries (Figure 15). Luckily, the tooth was asymptomatic. Having recently accepted a new job with dental benefits, he was now ready to proceed with the final full-coverage restoration that was recommended to be done immediately after finishing the endodontic treatment.

The treatment plan was straightforward in this situation. We decided to place a lithium disilicate (all-ceramic) crown (e.max [Ivoclar Vivadent]). For those not familiar, lithium disilicate is an extremely strong and durable full-contour monolithic ceramic restoration. For comparison purposes, traditional ceramics have a strength around 100 to 120 mPA, compared to 360 to 400 mPA for e.max. This strength allows lithium disilicate restorations to be either resin bonded or traditionally cemented. It also has the aesthetics and vitality you would expect from an all-ceramic. In my hands, e.max has been shown to be a successful posterior alternative to traditional PFM or zirconia-based all-ceramic restorations when indicated.

This case also provided a great opportunity to utilize a newly available and completely digital workflow system called CEREC Connect (Sirona Dental) for fabrication of the restoration via collaboration between the dental office and dental laboratory.

Clinical and Laboratory Procedures
Treatment began with the removal of the remaining temporary restoration and any recurrent caries (Figure 16), and confirming long-term restorability. Once I was confident that the tooth could be restored, I placed a bonded buildup, finalized the preparation according to material requirements, and completed the tissue retraction with a combination of diode laser (Picasso [AMD Lasers]) and cord (Figure 17) to allow complete visualization of the margin.

Where things change from traditional techniques is with the integration of CEREC digital impressions. Instead of taking a vinyl polysiloxane impression and mailing it to the dental laboratory, a few quick digital images are acquired with the CEREC Bluecam. Then, the data, along with a digital prescription, is immediately sent digitally to the laboratory through the secure CONNECT portal.

From a dental practice perspective, this digital workflow allows several advantages over traditional restoration fabrication techniques. The dental laboratory technicians receive the case within minutes and begin making the restoration. In fact, there have been times where I have received a restoration back from our dental technicians on the same day. All photographs are integrated into the laboratory prescription and sent with the digital impressions to aid the dental ceramist in matching the restorations. Optionally, the dentist has the ability to mark the margins prior to sending the case for situations where the margin may be unclear.

Once the dental technicians receive the digital impressions, they can decide to order digitally-printed models or to make the restoration directly without models. In this case, we jointly decided to opt for the use of a digitally-printed model. The laboratory receives the models ready for fabrication—pinned, sectioned, margins ditched, and articulated (Figure 18). Having a digital model allows the laboratory complete freedom in technique of making the restoration. In this case, the e.max restoration was created using the CEREC inLab milling unit. The margins and contacts were subsequently refined by the dental technician on the printed model (Figure 19).

The final restoration was returned to our office about 5 days after sending it to the laboratory. The patient returned to the office and the restoration was bonded using a self-etching dual cure resin cement (Multilink [Ivoclar Vivadent]). The final result is a strong and aesthetic digitally-fabricated restoration (Figure 20).