Celtra Press is the perfect material for the LABORATORY technician, dentist, and patient
By Edwin Kee, MCDT
CERAMICS such as lithium disilicate and zirconia have become the materials of choice among dentists and their laboratory partners for making single units to veneers to multi-unit bridges, and implant-supported restorations. Dental technicians have relied on these materials not only because of their esthetics and strength but also due in part to the limited choice of reliable materials available for current restorative challenges.
The author believes that we as technicians are all artists at heart, always seeking an ideal material solution that has the ability to harmonize with each individual smile to create the most natural looking results. Dental manufacturers are finally starting to offer alternative materials that have even higher strength and better esthetics than ever before; materials that will not “gray out,” have less reaction layer, and feature an opalescent chameleon effect that mimics natural teeth.
Dentsply Sirona Prosthetics recently launched Celtra® Press, an expansion to the Celtra product offering. Celtra Press is a pressable material composed of zirconia-reinforced lithium silicate (ZLS), made especially with laboratories in mind. This revolutionary new material option blends beautifully with natural dentition, providing the esthetics patients are searching for and the exceptional strength that dentists demand. Consider the following case study on how this material works to achieve superior restorative outcomes.
When this case presented itself, the patient’s main concern was the absence of her canine, which left a space between the premolar and laterals. In addition, her composite was staining and starting to chip (Figure 1). She told the dentist that she would like to have veneers in order to fix the erosion and to have a more natural looking smile.
Step-by-Step Production of Restorations
The referring dentist first removed the composites on the cervical of each tooth, and then prepped teeth Nos. 4 and 7-10 for veneers and teeth Nos. 5 and 12 for crowns due to decay. The model work was created and a wax-up of the full contour teeth Nos. 5 and 13 was made, as well as veneer coping wax-ups for teeth Nos. 4, 7-10, and 12 (Figure 2). We had to covert the premolars on both sides to canines. This was a real challenge since the space is significantly larger, and the premolars are in the incorrect position; we had to really work with the line angles.
The wax-ups were then sprued with a 6-gauge, 2.5-3-mm length sprue (Figure 3) and placed on the ring former. Because of its fine particle size, Celtra Press investment was used to provide the best pressing option available. The author highly recommends following the manufacturer’s pressing parameters for the water-to-powder ratio to ensure the best fit.
The investment was vacuum-mixed for 1 minute, then slowly poured into the ring to prevent any bubbles. The invested ring bench-set for 20 minutes and then placed into a hot oven at 850°C. After the rings were burned out, the full crowns were pressed in medium-translucency (MT) ingots, and the veneers were pressed in high-translucency (HT) ingots.
Once the ring was cool, the author divested it utilizing glass beads. The reaction layer that appears can easily be removed by sandblasting with alumina oxide (no more than 1.5 bars) (Figure 4). There was no need to add any solution to remove the reaction layer since it is extremely thin. The sprues were then removed with a diamond disk and then slightly reshaped with a diamond bur.
The restorations were tried onto the stone dies for comparison, and any adjustments to the occlusion and contacts were carefully examined. The tooth prep shade dies were made to mimic the patient’s natural overall tooth color utilizing Dentsply Sirona’s Die Material System. The composite material was then light-cured. Since Celtra Press is highly translucent, the prep shade dies further helped us to achieve the ideal end shade.
Crowns Nos. 5 and 12 and veneers Nos. 4 and 7-10 were then cut back minimally on the incisal one-third so that the porcelain and stains could be simultaneously placed on the crowns and veneers and could match all restorations perfectly (Figure 5).
The restorations were placed in the ultrasonic cleaner in order to remove any grinding particles and contaminants. After cleaning, the restorations were placed in the porcelain oven set on the Powerfire cycle, which increased the strength of these Celtra Press restorations to >500 MPa.
All the restorations were stained internally with Celtra stains and freeze-fired to the restoration (Figure 6). Celtra Ceram porcelain powders were then used to layer the restorations.
Effects powders and translucent enamels were added to produce more natural-looking restorations (Figure 7). The restorations were then shaped with fine diamond burs to create beautifully detailed, individualized anatomy in order to harmonize with the opposing teeth (Figure 8). The restorations were then glazed using Dentsply Sirona Universal Overglaze (Figures 9 and 10).
Shown here are the final restorations on the day of delivery (Figure 11). The patient was extremely happy with her new smile (Figure 12). Celtra Press is a great material that does not “gray out” even if HT ingots are used. It provides such a natural-looking restoration and has an exquisite chameleon effect that blends perfectly with its surroundings. Its strength, as well as the simple process and the esthetically pleasing results, make Celtra Press the perfect material for the dentist, lab technician, and, most importantly, the patient.
Edwin Kee, MCDT, is an Assistant Professor of Clinical Prosthodontics at Louisiana State University in New Orleans, Louisiana.