title: Bond strength and degree of infiltration between acrylic resin denture liner after immersion in effervescent denture cleanser.
abstract: OBJECTIVE
  The purpose of this study was to investigate the effect of sodium perborate on the bond strength and degree of infiltration between acrylic resin/resilient denture liners.
  
  
  METHODS
  Three denture liners (Elite Soft, Mucopren Soft, Kooliner) were investigated. Twenty specimens (83 x 10 x 10 mm(3)) of each material were made by processing the denture liners against two polymerized PMMA blocks. Ten specimens for each material were stored in artificial saliva at 37 degrees C (control group: TBS1), and the other ten specimens were stored in artificial saliva at 37 degrees C combined with sodium perborate (experimental group: TBS2). All specimens were placed under tension until failure in a Universal Testing Machine at a crosshead speed of 5 mm/min after 7 (T7) and 60 (T60) days (n = 5). Failure strength (MPa) was recorded, and mode of failure was characterized as cohesive, adhesive, or cohesive/adhesive. For the infiltration tests, ten circular specimens (14-mm diameter x 2-mm thick) of each material were stored in artificial saliva and 0.5% methylene blue at 37 degrees C (control group: I1), and ten specimens were stored in artificial saliva and 0.5% methylene blue at 37 degrees C combined with daily immersions for 5 minutes in an effervescent solution of sodium perborate (experimental group: I2). The degree of infiltration was obtained through photographs and using Software Image Tool after 120 days.
  
  
  RESULTS
  For Kooliner, the statistical test did not show a significant difference in the bond strength due to the influence of the immersion period or to the use of sodium perborate. Elite Soft presented a significant increase in the average tension in T7 and in T60 in both TBS1 and TBS2. Inversely, the Mucopren suffered a significant decrease in the tension value in the same period as the TBS1 group as well as in the TBS2. The infiltration percentage was analyzed with the Kruskal-Wallis test (26.18; p < 0.05), which indicated significant differences between the compared averages for the groups. Comparing the averages of materials, the statistical test did not show significant differences between the control (I1) and experimental (I2) groups after 120 days.
  
  
  CONCLUSIONS
  The use of sodium perborate did not promote significant alterations in the evaluated properties. Kooliner presented the best results.
authors.affiliation: Department of Dental Materials and Prosthodontics, School of Dentistry of Ribeirão Preto, Sao Paulo, Brazil.
authors.forename: Marina Xavier
authors.initials: MX
authors.lastname: Pisani
authors.forename: Cláudia Helena
authors.initials: CH
authors.lastname: Silva-Lovato
authors.forename: Antônio de Luna
authors.initials: Ade L
authors.lastname: Malheiros-Segundo
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Macedo
authors.forename: Helena Freitas Oliveira
authors.initials: HF
authors.lastname: Paranhos
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D001881:Borates / Q000737:chemistry*; D004396:Coloring Agents; D001840:Dental Bonding; D003763:Dental Leakage / Q000145:classification; D003764:Dental Materials / Q000737:chemistry*; D003799:Dental Stress Analysis / Q000295:instrumentation; D003819:Denture Bases; D003820:Denture Cleansers / Q000737:chemistry*; D003822:Denture Liners; D006801:Humans; D008422:Materials Testing; D008751:Methylene Blue; D019904:Polymethyl Methacrylate / Q000737:chemistry; D012464:Saliva, Artificial / Q000737:chemistry; D012828:Silicones / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013500:Surface Tension; D013696:Temperature; D013718:Tensile Strength; D013997:Time Factors
chemical_list: D000180:Acrylic Resins; D001881:Borates; D004396:Coloring Agents; D003764:Dental Materials; D003820:Denture Cleansers; D012464:Saliva, Artificial; D012828:Silicones; C103363:kooliner; D019904:Polymethyl Methacrylate; D008751:Methylene Blue; C027707:sodium perborate