Describe the features and functions of a dental furnace that enable firing of modern dental porcelains.

Describe the features and functions of a dental furnace that enable firing of modern dental porcelains.

1. Dental porcelain furnace technology has advanced over many years. The 2100°F air-fired porcelain gave way to 1800°F vacuum-fired porcelain. In the mid to late 60’s vertical muffles were introduced, along with programmable furnaces that did not require the technicians attendance constantly. Soon after, the clamshell furnace was introduced. Instead of the work rising up into the muffle chamber, the muffle chamber lowered itself down onto the platform. The big advantage here was that the work didn't vibrate off the platform.

2. Most dental furnaces have the following features:

3. • Furnace head – This provides insulation to contain the temperatures within the firing chamber.

4. • Firing chamber – This contains the QTK heating element, and thermocouple.

5. • Firing plate – This enables positioning of the saggar within the firing chamber

6. • Display screen – Enables control of the programmes and visualisation of the current status of the furnace.

7. • Keypad – Enables control of the programme.

8. • Cooling tray – Where hot and cold saggars can rest prior to placement in or after removal from the firing chamber.

9. • Vaccum pump – Enables a partial vacuum within the firing chamber.

10. • The muffle speed is controlled to provide a slow heating to prevent thermal shock.

11. • Muffle is also opened gradually to provide a slow cool also preventing thermal shock.

12. Now, there are extra benefits added to some dental furnaces, such as:

    • • Infrared technology that heightens the process reliability and allows for faster firing with high-quality results.
    • • An infrared thermal camera that automatically controls the pre-drying and closing processes.