title: Water flow in high-speed handpieces.
abstract: OBJECTIVE
  This study measured the water flow commonly used in high-speed handpieces to evaluate the water flow's influence on temperature generation. Different flow speeds were evaluated between turbines that had different numbers of cooling apertures.
  
  
  METHODS
  Two water samples were collected from each high-speed handpiece at private practices and at the School of Dentistry at São José dos Campos. The first sample was collected at the customary flow and the second was collected with the terminal opened for maximum flow. The two samples were collected into weighed glass receptacles after 15 seconds of turbine operation. The glass receptacles were reweighed and the difference between weights was recorded to calculate the water flow in mL/min and for further statistical analysis.
  
  
  RESULTS
  The average water flow for 137 samples was 29.48 mL/min. The flow speeds obtained were 42.38 mL/min for turbines with one coolant aperture; 34.31 mL/min for turbines with two coolant apertures; and 30.44 mL/min for turbines with three coolant apertures. There were statistical differences between turbines with one and three coolant apertures (Tukey-Kramer multiple comparisons test with P < .05).
  
  
  CONCLUSIONS
  Turbine handpieces with one cooling aperture distributed more water for the burs than high-speed handpieces with more than one aperture.
authors.affiliation: School of Dentistry, Ibirapuera University São Paulo, São Paulo, Brazil. bncavalcanti@uol.com.br
authors.forename: Bruno Neves
authors.initials: BN
authors.lastname: Cavalcanti
authors.forename: Paulo Isaías
authors.initials: PI
authors.lastname: Serairdarian
authors.forename: Sigmar Mello
authors.initials: SM
authors.lastname: Rode
mesh_terms: D001831:Body Temperature; D002056:Burns / Q000209:etiology / Q000517:prevention & control*; D003737:Dental Cavity Preparation / Q000295:instrumentation*; D003754:Dental High-Speed Equipment / Q000009:adverse effects; D003782:Dental Pulp / Q000293:injuries; D004867:Equipment Design; D017276:Friction; D006358:Hot Temperature / Q000009:adverse effects; D006801:Humans; D012212:Rheology; D018709:Statistics, Nonparametric; D018677:Tooth Injuries / Q000517:prevention & control*; D014867:Water
chemical_list: D014867:Water