DIN Standards Committee Dentistry
DIN 19405
Dentistry - High temperature sintering furnace - Test method for temperature measurement with separate thermocouple
Zahnheilkunde - Hochtemperatur-Sinterofen - Prüfverfahren für die Temperaturmessung mit separatem Thermoelement
Overview
In dentistry, sintering furnaces are used for sintering restorations made from oxide ceramics and from sintered metal. Significantly higher temperatures than those for firing dental ceramic masses containing silicates are necessary, for example, zirconium oxide (ZrO2) is typically sintered at a temperature of up to 1 700 °C. The sintering temperature is of vital importance for the properties of the sintered material. Too high a sintering temperature generally results in a larger grain size and can lead to a softening and consequently a deformation of the restoration. Too low a sintering temperature results in an inadequate sintering quality and possibly residual porosity. Incorrect sintering temperatures can result in low strength, discrepant colouration or low ageing resistance. Furthermore, a poor accuracy of fit owing to excessively low or uneven shrinkage can occur. This document describes the calibration of resistance-heated high temperature sintering furnaces by means of a separate thermocouple. The furnaces shall be calibrated ex works in the same way for all manufacturers at a temperature of 1 500 °C. In addition, the deviation in the actual temperature at 1 000 °C shall be determined and a maximum permissible deviation specified.
