title: Tensile Bond Strength between Soft Liners and Two Chemically Different Denture Base Materials: Effect of Thermocycling.
abstract: OBJECTIVE
  The bond strength of soft denture liner to a recently introduced denture base resin after thermocycling has not been compared to traditional denture base materials. The objective of this study was to investigate the effects of thermocycling on the tensile bond strength of soft denture liners to two chemically different denture base resins, polymethyl methacrylate (PMMA) and urethane dimethacrylate (UDMA).
  
  
  METHODS
  A total of 48 PMMA and UDMA tensile test specimens were fabricated by attaching two different soft denture liners (Molloplast-B, Permaflex) according to the manufacturers' instructions and assigned to two groups. Half of the specimens for each group were stored in water for 1 week, and the other half were thermocycled (5000 cycles) between baths of 5°C and 55°C. Specimens were mounted on a universal testing machine with a 5 mm/min crosshead speed. The data were analyzed with three-way ANOVA and post hoc Tukey-Kramer multiple comparisons tests (α = 0.05).
  
  
  RESULTS
  The highest bond strength was measured in the specimens from the UDMA/Molloplast groups, and the lowest was seen in the PMMA/Permaflex group. No significant difference in bond strength was detected in PMMA/Permaflex groups after thermocycling (p = 0.082), whereas other groups exhibited significant differences after thermocycling (p < 0.05).
  
  
  CONCLUSIONS
  Thermocycling decreased the bond strength values in both the PMMA and UDMA groups. Regardless of types of soft liners, PMMA specimens presented lower bond strength values than UDMA specimens, both before and after thermocycling.
authors.affiliation: Department of Prosthodontics, Faculty of Dentistry, Cumhuriyet University, Sivas, Turkey.
authors.forename: Faik
authors.initials: F
authors.lastname: Tugut
authors.affiliation: Department of Prosthodontics, Faculty of Dentistry, Cumhuriyet University, Sivas, Turkey.
authors.forename: Mehmet Emre
authors.initials: ME
authors.lastname: Coskun
authors.affiliation: Department of Prosthodontics, Faculty of Dentistry, Cumhuriyet University, Sivas, Turkey.
authors.forename: Derya Ozdemir
authors.initials: DO
authors.lastname: Dogan
authors.affiliation: Department of Prosthodontics, Faculty of Dentistry, Akdeniz University, Antalya, Turkey.
authors.forename: Omer
authors.initials: O
authors.lastname: Kirmali
authors.affiliation: Department of Prosthodontics, Faculty of Dentistry, Cumhuriyet University, Sivas, Turkey.
authors.forename: Hakan
authors.initials: H
authors.lastname: Akin
mesh_terms: D000180:Acrylic Resins; D001840:Dental Bonding; D003819:Denture Bases; D003822:Denture Liners; D004129:Dimethylpolysiloxanes; D006801:Humans; D008422:Materials Testing; D019904:Polymethyl Methacrylate; D012826:Silicone Elastomers; D013499:Surface Properties; D013718:Tensile Strength
chemical_list: D000180:Acrylic Resins; D004129:Dimethylpolysiloxanes; C020964:MDX 4-4210; D012826:Silicone Elastomers; D019904:Polymethyl Methacrylate
keywords: PMMA; UDMA; soft denture liner; tensile bond strength; thermocycling