title: Influence of surface treatments on the flexural strength of denture base repair.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the flexural strength of repairs made with autopolymerising acrylic resin after different treatments of joint surfaces.
  
  
  METHODS
  Fifty rectangular specimens were made with heat-polymerised acrylic resin and 40 were repaired with autopolymerising acrylic resin following joint surface treatments: group 1 (intact specimens), group 2 (chemical treatment: wetting with methyl-methacrylate for 180 s), group 3 (abraded with silicon carbide paper), group 4 (abraded and wetting with methyl-methacrylate for 180 s) and group 5 (without surface treatment). The flexural strength was measured by a three-point bending test using a universal testing machine with a 100 Kgf load cell in the centre of repair at 5 mm/min cross-head speed. All data were analysed using one-way anova and Tukey HSD test for multiple comparisons (p < 0.05).
  
  
  RESULTS
  Among repaired specimens, groups 2 and 4 had 66.53 ± 3.4 and 69.38 ± 1.8 MPa mean values and were similar. These groups had superior flexural strength than groups 3 and 5 that were similar and had 54.11 ± 3.4 and 51.24 ± 2.8 MPa mean values, respectively. Group 1 had a mean value of 108.30 ± 2.8 MPa being the highest result.
  
  
  CONCLUSIONS
  It can be concluded that the treatment of the joint surfaces with methyl-methacrylate increases the flexural strength of denture base repairs, although the strength is still lower than that observed for the intact denture base resin. Abrasion with sandpaper was not able to influence the flexural strength of repaired denture bases.
authors: Department of Dental Materials and Prosthodontics, Araraquara Dental School, UNESP-São Paulo State University, Araraquara, SP, Brazil. rodrigopeco@yahoo.com.br
authors: Rodrigo de Paula
authors: Rde P
authors: Pereira
authors: Carina Sinclér
authors: CS
authors: Delfino
authors: Luis Eduardo
authors: LE
authors: Butignon
authors: Marcos André Kalabaide
authors: MA
authors: Vaz
authors: João Neudenir
authors: JN
authors: Arioli-Filho
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D000465:Algorithms; D017554:Carbon Compounds, Inorganic / Q000737:chemistry; D045662:Dental Etching / Q000379:methods; D003764:Dental Materials / Q000737:chemistry; D003799:Dental Stress Analysis / Q000295:instrumentation; D003819:Denture Bases; D003780:Denture Repair; D055119:Elastic Modulus; D006801:Humans; D008422:Materials Testing; D020366:Methylmethacrylate / Q000737:chemistry; D018583:Pliability; D017655:Silicon Compounds / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D000180:Acrylic Resins; D017554:Carbon Compounds, Inorganic; D003764:Dental Materials; D017655:Silicon Compounds; D014867:Water; D020366:Methylmethacrylate; C022088:silicon carbide