title: An investigation of the effect of powder reservoir volume on the consistency of alumina powder flow rates in dental air-abrasion devices.
abstract: OBJECTIVE
  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 alpha-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 60s 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 microm and 50 microm abrasive (70% and 69%, respectively), whereas, smaller differences were seen with the Abradent (59%), Aquacut 29 microm and 53 microm abrasive (62% and 30%) and MicroPrep (35%) machines.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Conservative Dentistry, King's College London Dental Institute at Guy's, King's College & Saint Thomas' Hospitals, Guy's Dental Hospital, London Bridge, London SE1 9RT, UK. avijit.banerjee@kcl.ac.uk <avijit.banerjee@kcl.ac.uk>
authors.forename: Avijit
authors.initials: A
authors.lastname: Banerjee
authors.forename: Mohsin
authors.initials: M
authors.lastname: Uddin
authors.forename: G
authors.initials: G
authors.lastname: Paolinelis
authors.forename: Timothy F
authors.initials: TF
authors.lastname: Watson
mesh_terms: D020906:Air Abrasion, Dental / Q000295:instrumentation*; D000537:Aluminum Oxide / Q000032:analysis*; D000704:Analysis of Variance; D011312:Pressure
chemical_list: D000537:Aluminum Oxide