DESIGN OF A NOVEL THERMO-ELECTRIC COOLING DEVICE CAPABLE OF ACHIEVING CRYOGENIC TEMPERATURES FOR DENTAL PULP TESTING

Abstract

Dental pulp testing is a diagnostic test in endodontics to test whether the dental pulp is dead or alive. Thermal tests (cold and hot) and electrical pulp testing techniques are two of the most common pulp sensibility tests currently being used. Although cold tests have shown more promising results in comparison to other techniques, the current methods used for cold testing have safety concerns as they involve direct application of the cold agent to the tooth. This study proposed a thermoelectric cooling based dental pulp testing device capable of achieving cryogenic temperatures and varying this temperature below 0℃ up to -60℃. This device is safe in operation and provides availability for on-site application due to its portability and stand-alone features. Thermoelectric cooling is based on the Peltier effect, which allows a temperature difference across a thermoelectric module and results in one side of the module becoming cold while the other side becomes hot. The challenge for such devices based on the Peltier effect is that the heat on the hot side of the module needs to be dissipated so that it is not too hot to burn the patient’s skin. This study explored the application of the phase change cooling technique in the form of heat pipes and vapor chambers to address this challenge. Finally, a thermoelectric cooling system capable of achieving -60℃ at the probe for pulp sensibility testing was proposed through modeling and simulation in Comsol Multiphysics software and experimentally validated using off-the-shelf hardware.