Esthetic Rehabilitation of the Patient with Attrition
Utilizing KATANA UTML zirconia and a CAD/CAM process for a strong, natural-looking result
By Sean Han, CDT
Advancements in materials and CAD/CAM technology have provided new treatment options for the dental team when handling unusual cases. When the dentist and the laboratory communicate effectively, they can optimize their use of these new options. The following case presents one such situation.
A female patient expressed esthetic concerns and presented with teeth that had attrition. Her smile esthetic plane was canted due to the gingival plane, which was not level with her interpupillary line (Figure 1). The treatment plan was to provide the patient with esthetic gingival crown lengthening and crowns on teeth Nos. 6-11, and the dentist, Steve Lim, DMD, of the Center for Advanced Dentistry in San Jose, California, wanted all-ceramic crowns. However, because of the planned esthetic crown-lengthening procedure, the ideal shoulder margin preparation for all-ceramic restorations was not possible. The patient also had severe bruxism, which called for a strong material, and she had multiple stump shades, so zirconia was an ideal choice. The author chose Kuraray Noritake’s KATANA UTML in the shade B1, because it is multi-layered and highly predictable.
Using Dentsply Sirona’s inLab SW15, the author designed the 6-unit restoration with an emphasis on proper arch line and midline (Figure 2). In the model phase, the correct axis was set (Figure 3). The thickness of each restoration was between 0.8 mm and 1.2 mm, and each was checked and planned in the software (Figure 4). Dentsply Sirona’s MC X5 was used to mill the Katana UTML Shade B1.
Next, the author removed the sprues (Figure 5) using a fine carbide 702 bur, and then used a fine diamond point to detail the buccal anatomy. A silicone rubber point was used to smooth the surface all around. The restorations then went in for sintering using Dentsply Sirona’s inFire on an 8-hour cycle; they were held for 2 hours at 1550°C and cooled at 10°C/minute until they reached room temperature, as instructed by Kuraray Noritake.
Figure 6 shows the result after sintering. A fine diamond was then used to create natural anatomy and line angles on the facial, and the restorations were fine polished on the lingual using Kuraray Noritake’s Pearl Surface paste and diamond polish. The author sandblasted using aluminum oxide at 3 bar, steam cleaned, and let the restorations sit in room-temperature distilled water to eliminate any contamination while carefully air drying and glazing each restoration (Figure 7).
The author applied liquid glaze on the restoration. Blue/gray stains were applied on the facial incisal edge, vanilla stain at the height of the contour, and chromatic stain—one-third on the lateral, one-half on the canine, and none on the centrals (Figure 8 and Figure 9).
On the lingual, the author applied vanilla stain on the incisal edge, followed by blue stain. On the lingual fossa, light orange was applied, followed by mahogany on the pits and fissures (Figure 10). The same light orange was applied on the mesial and distal of each restoration.
The crowns were left to dry for 5 minutes in the furnace and heated at a rate of 55°C per minute up to 850°C with a vacuum, staying for 1 minute at the high temperature. On the second bake, fluorescent glaze was applied all around and anywhere on the restorations lacking natural color. The author reapplied the same stains from the first bake, and the lingual was carefully polished to prevent opposing wear and longevity (Figure 11). Cementation was accomplished using PANAVIA™ V5 in shade A2 Universal to add warmth and exceptional zirconia bond strength.
The patient was extremely happy with the final results (Figure 12 through Figure 14), as her expectations were met and exceeded in terms of smile esthetics and attrition treatment, strength, esthetics, and a precise fit. The author also desired predictable results with the restorations. Communication between the dentist and the laboratory allowed them to choose the ideal material given the limitations of the case, including the patient’s bruxism and her request for esthetic all-ceramic material and a crown-lengthening procedure. The dentist’s delivery chair time was also quick and smooth with the PANAVIA™ V5 cement system, allowing more time with the patient to explain post-operatory instructions. Utilizing the combination of CAD/CAM technology and ideal zirconia material, the technician, the dentist, and most importantly the patient were pleased with the results.
Sean Han, CDT, is the Chief Technology Officer and President of Image Dental Group in Santa Clara, CA.
Watch a video demonstrating the benefits of Kuraray Noritake’s KATANA ML zirconia at insidedentaltech.com/idt899.
Kuraray America, Inc.
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