An investigation of the effect of powder reservoir volume on the consistency of alumina powder flow rates in dental air-abrasion devices

Abstract

Objectives To investigate the effect of powder reservoir fill volume on the emitted alumina powder flow rate of four dental air-abrasion units. The null hypothesis examined was that powder reservoir fill volume has no effect on α-alumina powder flow rate. Methods The spent alumina powder from the four air-abrasion units tested (Abradent, Crystalmark, Clendale, CA, USA; Aquacut, Velopex, Horesham, UK; MicroPrep Associate Lares, Chico, CA, USA; Rondoflex 360, KaVo, Lake Zurich, IL, USA) was gathered in a collecting chamber over a 60 s running period. The difference in the weight pre- and post-collection was noted and flow rate calculated for different reservoir fill volumes (100%, 75%, 50% and 25%). Results The powder flow rate of each machine was significantly affected by a change in powder reservoir volume ( p < 0.05). In all devices a partially empty reservoir caused a significant decrease in powder flow rate, compared to that at maximum fill volume. The maximum percentage difference seen using the Rondoflex was similar for 27 μm and 50 μm abrasive (70% and 69%, respectively), whereas, smaller differences were seen with the Abradent (59%), Aquacut 29 μm and 53 μm abrasive (62% and 30%) and MicroPrep (35%) machines. Conclusion It was shown that the fill of the reservoir affects the powder flow rate of air-abrasion units, thus disproving the null hypothesis. In a clinical setting and in future research studies, the powder reservoir should be filled to a set level to achieve a constant and reproducible cutting performance of the tested units.