Using a washer, disinfector, lubricator, and dryer to test the effectiveness of cleaning dental handpieces

Abstract

Objectives: When using dental handpieces (HP), a phenomenon of backflow leads to an external and internal soiling and contamination of HP, especially in their narrow air/water pipes. To prevent any cross-infection, HP need to be sterilized after a thorough cleaning. This work aims to establish and assess a method for testing their cleaning. Indeed, there is a methodological gap concerning its validation because of their complex architecture.
Materials and Methods: This method is declined into a protocol using artificial soilings and ninhydrin tests. Its evaluation with a washer-disinfector-lubricator-dryer (WDLD) within 2 cleaning cycles with each 6 HP and after control tests, heads to validate its relevance and to demonstrate the effectiveness of the cleaning provided.
Results: After each cycle, all HP were externally clean. Our method also showed an internal cleanliness except for 2 HP whose engines in the automaton were defective.
Conclusion: This work fits with the improvement of infection control in dental practices. It is the first method developed to control the internal cleaning of HP without having to break them, and it demonstrates the need for HP to be put into an internal rotation during their cleaning. It fills the methodological gaps concerning their cleaning and allows assessing HP cleaning from dedicated WDLD. According to standard NF EN ISO15883, the method could be used for initial steps of operational or performances qualifications concerning HP cleaning.