Devices are known for performing microwave-sterilization of medical and dental instruments. A microwave-sterilization device for dental instruments, for example, is discussed in PCT WO 93/18798 in which a sealed pouch--with instruments located inside--is positioned with at least an instrument retaining portion of the pouch between two microwave shields. The shields form a microwave shield chamber that is disposed around the metal instruments. As is well-known, the shield chamber prevents the transmission of microwave radiation to the metal instruments, as the unrestricted transmission of the microwave radiation would cause unwanted heating or arcing of the instruments and result in damage.
During the sterilization process, the microwave-sterilization device is placed in a common residential or commercial microwave oven and the microwave energy generated by the oven is used to vaporize a sterilization fluid such as water. The steam produced from the sterilization fluid is introduced into the instrument portion of the pouch to sterilize the instruments contained therein. The temperature of the pouch reaches a temperature of over 133 degrees centigrade during the sterilization process and must be maintained over a predetermined period of time to guarantee the instruments contained therein are properly sterilized.
In order to guarantee that the sterilization process is successful, it is important to monitor the temperature of the pouch to make certain that the proper sterilization temperature has been reached during the sterilization process. Conventional temperature sensors developed for microwave ovens, however, have been found to degrade over time at the temperatures associated with the sterilization process. In addition, the conventional sensors have an insufficient degree of accuracy, a low response time, to much signal noise, and do not interface well with the pouches utilized in the type of microwave-sterilization device discussed above.