title: Coolant effectiveness in dental cutting with air-turbine handpieces.
abstract: OBJECTIVE
  To establish a strategy for evaluating coolant effectiveness and to compare typical cooling conditions used in dental cutting.
  
  
  METHODS
  A test system comprising a resistive heat source and an array of four type K thermocouples was used to compare the cooling effectiveness of air alone, water stream alone, and an air-water spray, as delivered by representative air-turbine handpieces. Mean temperature change at the four sites was recorded for a range of water flow rates in the range 10 to 90 mL min(-1), with and without air, and with and without the turbine running. The thermal resistance of the system, R, was calculated as the temperature change per watt (KW(-1)).
  
  
  RESULTS
  For wet cooling (water stream and air-water spray), R was 5.1 to 11.5 KW(-1), whereas for air coolant alone the range was 18.5 to 30.7 KW(-1). R for air-water spray was lower than for water stream cooling at the same flow rate.
  
  
  CONCLUSIONS
  The thermal resistivity approach is a viable means of comparative testing of cooling efficacy in simulated dental cutting. It may provide a reliable means of testing handpiece nozzle design, thus enabling the development of more efficient cooling.
authors.affiliation: Faculty of Dentistry, The University of Hong Kong, Hong Kong.
authors.forename: Brian T W
authors.initials: BT
authors.lastname: Leung
authors.forename: John E
authors.initials: JE
authors.lastname: Dyson
authors.forename: Brian W
authors.initials: BW
authors.lastname: Darvell
mesh_terms: D000388:Air; D003080:Cold Temperature; D003754:Dental High-Speed Equipment / Q000592:standards*; D018130:Diamond / Q000737:chemistry; D004867:Equipment Design; D045268:Flowmeters; D006801:Humans; D057446:Hydrodynamics; D012212:Rheology / Q000295:instrumentation; D013696:Temperature; D013814:Thermal Conductivity; D014867:Water / Q000737:chemistry
chemical_list: D014867:Water; D018130:Diamond