Compliance of the Dryness of Dental Handpieces for Their Sterilization under Various Treatment Conditions

Objectives: In the protocol for cleaning and sterilizing dental handpieces (DHs), water retention within the instrument poses a challenge and may compromise the sterilization process. This study aimed to assess the reliability and reproducibility of the sterilization protocol regarding the dryness of DHs. It evaluated the presence of residual water in these instruments after various conditions of treatment through multiple dryness tests. Methods: This comparative study examined the dryness of seven different DHs following five washing–disinfection and/or sterilization protocols. Dabbing tests, shaking by hand, or compressed air tests through DHs and over absorbent paper were employed to ascertain the thorough dryness of DHs after treatment. As soon as the first sign of water appeared on the absorbent paper, the DH was deemed to be not dry. Results: Upon completion of the washing–disinfection protocol without sterilization, five out of seven DHs were deemed dry using the dabbing test, yet none were fully dry when subjected to shaking or compressed air. However, in the four protocols incorporating final sterilization, all DHs were dry according to the three drying tests. Conclusion: This study underscores the essential role of the sterilization step in eliminating residual water from DHs, thereby ensuring optimal conditions for effective sterilization in terms of dryness. Furthermore, the study recommends against relying solely on the dabbing drying test, emphasizing the importance of shaking or using compressed air to confirm instrument dryness.