In-vitro assessment of oral fluid aspiration by various high-speed air-turbine dental handpieces

Background: The control of aspiration contamination of dental handpiece (DHP) is crucial for mitigating cross-infection risks associated with dental chair units (DCUs) and DHP. However, the anti-aspiration capabilities of DHPs are predominantly asserted by manufacturers, with an absence of standardized methodologies to assess these claims. Aim: To evaluate the anti-aspiration performance and the mechanism of DHPs to improve cross-infection prevention strategies. Methods: Five different manufacturers of DHPs included SMART torque S609C (Group SMART), TWINPOWER TURBINE 4H PAR-4HUEX (Group TWIN), T3 mini-Midwest (Group T3), TU (Group TU) and disposable DHP (Group Hpdove) were selected. The aspiration pressure index was compared by the changes in liquid levels. The colony counts of Streptococcus mutans in connecting tubes of the DCU were compared under model F (full DHP head immersion) and model H (half dental bur immersion). Findings: Group TWIN exhibited zero aspiration pressure index, indicating zero aspiration pressure. Under model H, the bacterial counts were observed in the exhaust tubes of four groups (P < 0.001), excluding group TWIN. The bacterial counts in exhaust tubes under model H were significantly lower than those under model F (P < 0.003). Conclusion: The TWIN DHP demonstrating the best anti-aspiration capability with lowest aspiration pressure index and the least bacterial counts in the exhaust tubes was under model H. Half dental bur immersion reduces the risk of cross-infection compared with full DHP head immersion. The anti-aspiration analysis model developed in this study could serve as the basis for an ISO to benchmark DHP manufacturer claims and help control the cross-infection risks associated with DCU. (c) 2025 The Healthcare Infection Society. Published by Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.