What is Thermal Shock?

Thermal shock is a common cause of handpiece failure. As the name suggests thermal shock is a forced or sudden change of temperature from hot to cold.

Thermal shock in dental handpieces occurs when the sterilising cycle has just completed, and the team is under pressure to get the handpiece back to the dentist for the next patient. The handpiece is too hot to handle and the quickest way of cooling it is to dunk it under cold running water from the tap.

The Science Bit:

All material expands when heated and contracts when cooled. The components inside the handpiece are very finely engineered and compromise of different materials which expands and contracts at different rates. They have expanded in the steriliser and need to cool down naturally in room temperature.

If the handpiece is plunged under a cold running tap after sterilising the components are forced to cool rapidly. This usually results in the turbine splitting, the bearing housing shattering or the burr retaining mechanism jamming.

Thermal shock is recognised by a split on the turbine part of the cartridge as can be seen above. Note how the edges was damaged in the middle image when trying to remove it from the handpiece. It had split so much it was jammed in the head.

This type of damage would not be covered under warranty by any manufacturer.

Always allow handpiece to cool down naturally at room temperature after sterilising.