Effectiveness of two devices designed to prevent fluid retraction in a high-speed handpiece

Abstract

Statement of Problem: Contaminated fluid can be retracted into the turbine air chamber of a high-speed handpiece when it stops rotating. Purpose: This study attempted to evaluate 2 operating systems recently equipped with antiretraction devices installed inside the handpiece (Kavo) or inside the unit (Castellini) and to compare the results with those obtained from an operating system without any antisuction device (Bien Air). Material and Methods: Two test conditions (bur immersed approximately 5 mm into a dye solution or completely immersed in dye solution) were conducted using potassium bichromate dye to simulate a fluid contaminant. Results: During the first procedure dye influx for the Kavo unit was 0.08 ± 0.1 μL, 0.06 ± 0.1 μL for the Castellini unit, and 12.4 ± 5.2 μL for the Bien Air unit (F=28.3; P <.01). During the second procedure, the results of the dye influx were Kavo unit 2.52 ± 1.3 μL, Castellini unit 0.1 ± 0.1 μL, and Bien Air unit 22.22 ± 4.0 μL (F=123; P <.01). Mean values were significantly different between Castellini and Kavo units during the second procedure. Conclusion: Antisuction devices can reduce dye penetration into the air chamber of a high-speed handpiece. Better results may be obtained with devices installed inside the unit and designed to increase the air pressure in the air chamber when the turbine stops running. (J Prosthet Dent 2000;84:225-8.)