title: Evaluation of mechanical and thermal properties of commonly used denture base resins.
abstract: OBJECTIVE
  The purpose of this investigation was to evaluate and compare the mechanical and thermal properties of 6 commonly used polymethyl methacrylate denture base resins.
  
  
  METHODS
  Sorption, solubility, color stability, adaptation, flexural stiffness, and hardness were assessed to determine compliance with ADA Specification No. 12. Thermal assessments were performed using differential scanning calorimetry and dynamic mechanical analysis. Results were assessed using statistical and observational analyses.
  
  
  RESULTS
  All materials satisfied ADA requirements for sorption, solubility, and color stability. Adaptation testing indicated that microwave-activated systems provided better adaptation to associated casts than conventional heat-activated resins. According to flexural testing results, microwaveable resins were relatively stiff, while rubber-modified resins were more flexible. Differential scanning calorimetry indicated that microwave-activated systems were more completely polymerized than conventional heat-activated materials.
  
  
  CONCLUSIONS
  The microwaveable resins displayed better adaptation, greater stiffness, and greater surface hardness than other denture base resins included in this investigation. Elastomeric toughening agents yielded decreased stiffness, decreased surface hardness, and decreased glass transition temperatures.
authors.affiliation: Department of Prosthodontics, The University of Texas Health Science Center, San Antonio, TX 78229-3900, USA.
authors.forename: Rodney D
authors.initials: RD
authors.lastname: Phoenix
authors.forename: Michael A
authors.initials: MA
authors.lastname: Mansueto
authors.forename: Neal A
authors.initials: NA
authors.lastname: Ackerman
authors.forename: Robert E
authors.initials: RE
authors.lastname: Jones
mesh_terms: D000327:Adsorption; D000704:Analysis of Variance; D002152:Calorimetry, Differential Scanning; D003116:Color; D003819:Denture Bases; D006244:Hardness; D006358:Hot Temperature; D006801:Humans; D008422:Materials Testing; D008872:Microwaves; D018583:Pliability; D019904:Polymethyl Methacrylate / Q000737:chemistry*; D012995:Solubility; D013314:Stress, Mechanical; D013499:Surface Properties; D013816:Thermodynamics
chemical_list: D019904:Polymethyl Methacrylate