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Proper calibration and spruing techniques are just two of the ways to ensure you're getting the most accurate results with Ivoclar Vivadent¹s Programat® Pressing Furnaces.
Use a dedicated circuit for your furnace. The Programat EP 3000 and EP 5000 models are designed to perform optimally with standard voltage input. Draw from other equipment can cause fluctuations in voltage and alter the furnace's performance.
Calibrate your furnace every 50 press cycles. Both pressing furnaces have an automatic double-range calibration system—called ATK 2—that enables precise calibration for both low-fusing and conventional temperature ranges. A new ATK 2 Automatic Temperature Checking Set is required for each calibration in order to verify and adjust the temperature in the furnace chamber.
Always be sure you're using the latest version of the software. Software downloads can be found at the Download Center at www.ivoclarvivadent.com/downloadcenter and transferred to the furnace via USB or PC and download cable. Note: user-created programs will be overwritten in the software update process so a data backup is recommended.
Use the appropriate sprue length. Sprues should be 3mm to 8mm long and attached so the ceramic flows from thicker into thinner areas. The combined length of the waxup and sprue should not exceed 16mm (see Figure 1).
Place wax patterns on the sprue base at a 45-60° angle. This allows restorations to sit in the "hot zone" of the ring. Use the IPS e.max Sprue Guide (Figure 2) to verify proper sprue positioning.
To facilitate investing, sprue the restoration with the margin facing up. This helps the material to flow outward into a more uniform heat zone. For full contour restorations, having the margins face up helps ensure that material doesn't have to flow back to the center of the ring as it fills the occlusal morphology.
Use PressVEST or PressVEST Speed investment for predictability (see Figure 3). The pressing parameters of Programat furnaces were developed for these investments; some investments are higher in density and don't transfer heat in the same manner (the higher the density of investments, the lower the temperature in the center of the ring). Also, be sure to adhere to the proper mixing/setting times and burnout schedule.
Use an Alox plunger treated with plunger separator rather than a disposable plunger. Disposable plungers have a lower density than Alox plungers (see Figure 4) and may alter the temperature profile in the ring. Additionally, dimensions of after-market plungers can vary, leading to a fit that's too loose or tight in the investment mold.
Insert the ring into the press furnace within 30 seconds of removing it from the burnout oven to avoid significant cooling of the investment. If your burnout oven is in a different room than the press furnace, for example, the ring will lose too much heat which could result in a short pressing.
Be sure your burnout furnace is also correctly calibrated. Pressing parameters have been set based upon a known starting temperature from the burnout oven of 1,562°F (850°C). Any deviation in this starting temperature can result in inaccuracies such as an excessive reaction layer, short pressings and optical changes to the shade or translucency.
Ivoclar Vivadent Programat® Pressing Furnaces: EP 3000/G2 and EP 5000/G2 Models
The Programat EP 5000/G2 combination press and ceramic furnace features electronic press drive, Intelligent Press Function and QTK heating muffle technology for homogeneous heat distribution. Its Crack Detection System identifies cracks in the investment ring early enough to abort the press procedure. The EP 5000/G2 also offers a user-friendly menu control and the Optical Status Display allows you to easily see the status of the restoration.
The Programat EP 3000/G2 offers many of the same features as the 5000/G2 in a simpler, more cost-effective version. It's easy to operate and offers both standard press programs and the ability to save individual programs.
Both furnaces also feature Power Saving Technology; in standby mode, the furnaces' power consumption drops by nearly 40% to save electricity and protect the environment. For more information, contact Ivoclar Vivadent at 800-533-6825 or visit www. ivoclarvivadent.us.
© 2015 LMT Communications, Inc. · Articles may not be reprinted without the permission of LMT
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