title: Evaluation of tensile bond strength of heat cure and autopolymerizing silicone-based resilient denture liners before and after thermocycling.
abstract: OBJECTIVE
  To assess the effect of simulated mouth conditions reproduced with thermocycling on the tensile bond strength of two silicone based resilient denture liners with acrylic resin bases.
  
  
  METHODS
  Two silicone-based soft denture liners (Mollosil - Chairside autopolymerization and Molloplast B - Heat polymerization) were tested. For each liner, 30 specimens with a cross-sectional area of 10 Χ 10 mm and thickness 3 mm were processed between two acrylic blocks (Trevalon). Specimens were divided into a control group that was stored for 24 hours in water at 37°C and a test group that was thermocycled (2500 cycles) between baths of 5° and 55°C. Tensile bond strength (kg/cm²) was determined in a universal testing machine using crosshead speed of 5 mm/min.
  
  
  METHODS
  The student t-test was used to determine the significance of the difference in bond strength between the two liners.
  
  
  RESULTS
  The mean tensile bond strength for control and thermocycled specimens of the two liners were: Mollosil (6.82 kg/cm² and 8.41 kg/cm²) and Molloplast-B (16.30 kg/cm² and 13.67 kg/cm²), respectively. Comparison of bond strength of control specimens with thermocycled specimens of the liners indicated a significant difference for both Mollosil (P=0.045) and Molloplast-B (P=0.027). Comparison between control specimens of both liners and thermocycled specimens of both liners indicated a highly significant difference (P<0.001).
  
  
  CONCLUSIONS
  Heat polymerized resilient denture liner Molloplast-B had higher tensile bond strength than autopolymerizing liner Mollosil regardless of thermocycling. The bond strength of Mollosil increased after thermocycling while that of Molloplast-B decreased after thermocycling.
  
  
  CONCLUSIONS
  Although heat-polymerized denture liners require more processing time than autopolymerizing liners, but they display much better adhesion properties to denture base resin and should thus be preferred when soft liner has to be used for a longer duration of time.
authors: Department of Prosthodontics, Punjab Government Dental College and Hospital, Amritsar, Punjab, India.
authors: Nishtha
authors: N
authors: Madan
authors: Kusum
authors: K
authors: Datta
mesh_terms: D001840:Dental Bonding; D003764:Dental Materials / Q000737:chemistry; D003799:Dental Stress Analysis / Q000295:instrumentation; D003819:Denture Bases; D003822:Denture Liners; D004129:Dimethylpolysiloxanes / Q000737:chemistry; D006358:Hot Temperature; D006801:Humans; D008422:Materials Testing; D008768:Methylmethacrylates / Q000737:chemistry; D058105:Polymerization; D012826:Silicone Elastomers / Q000737:chemistry*; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength; D014867:Water / Q000737:chemistry
chemical_list: D003764:Dental Materials; D004129:Dimethylpolysiloxanes; C020964:MDX 4-4210; D008768:Methylmethacrylates; C483159:Mollosil Plus; D012826:Silicone Elastomers; D014867:Water; C029883:Trevalon universal