title: Influence of temperature on the spreading velocity of simplified-step adhesive systems.
abstract: BACKGROUND
  Flowability and viscosity vary for different adhesive systems owing to differences in their composition. These characteristics can be modified by environmental temperature.
  
  
  OBJECTIVE
  The purpose of this study was to determine the influence of temperature on the spreading (flow capacity) of simplified-step adhesive systems.
  
  
  METHODS
  Spreading velocities of adhesive systems (Adper Single Bond and Single Bond Plus [3M ESPE, St. Paul, MN, USA]; Prime & Bond 2.1 and Prime & Bond NT [Dentsply Indústria e Comércio Ltda, Petrópolis, RJ, Brazil]; Adper Prompt [3M ESPE]; and One Up Bond F [Tokuyama Corp, Tokyo, Japan]) were analyzed at intervals of 10, 15, 20, and 30 seconds at both 25 degrees C and 37 degrees C by placing 10 microL drops on a glass slide surface with an inclination of 45 degrees. The spreading of each adhesive system was measured in millimeters per second.
  
  
  RESULTS
  Data were analyzed by two-way analysis of variance and Student-Newman-Keuls tests. Regression analysis was used to determine a correlation between spreading velocity and time. Statistical significance was considered at a confidence level of 95%. Temperature influenced the spreading velocity, increasing it for Single Bond and Prime & Bond 2.1 and decreasing it for Adper Prompt (p < .05). No differences on spreading were observed for the other adhesives studied (p >.05). Regression analysis of each adhesive system demonstrated an inverse correlation between mean spreading velocity and time (R2 = .999) on both temperatures.
  
  
  CONCLUSIONS
  Temperature increases yielded an increase of spreading for Single Bond and Prime & Bond 2.1. The influence of temperature on the spreading velocity was material dependent.
  
  
  CONCLUSIONS
  Environmental temperature can influence the rate of spreading of the adhesive system in clinically relevant times and may influence adhesive thickness on cavity walls.
authors.affiliation: Bauru Dental School, University of São Paulo, Brazil.
authors.forename: Flávia Bittencourt
authors.initials: FB
authors.lastname: Pazinatto
authors.forename: Luiz
authors.initials: L
authors.lastname: Marquezini
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Atta
mesh_terms: D000096:Acetone / Q000737:chemistry; D000269:Adhesives / Q000737:chemistry*; D000704:Analysis of Variance; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D010755:Organophosphates / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D012044:Regression Analysis; D019279:Resin Cements / Q000737:chemistry*; D012212:Rheology; D018709:Statistics, Nonparametric; D013499:Surface Properties; D013696:Temperature; D014783:Viscosity; D014906:Wetting Agents
chemical_list: D000269:Adhesives; C489661:Adper Prompt Self-Etch; D017220:Dentin-Bonding Agents; D008689:Methacrylates; C446260:One-Up-Bond F; D010755:Organophosphates; D011109:Polymethacrylic Acids; C425843:Prime and Bond NT; D019279:Resin Cements; C511238:Single Bond Plus; D014906:Wetting Agents; C444444:prime and bond 2.1; C115612:single bond; D000096:Acetone; D017438:Bisphenol A-Glycidyl Methacrylate