title: A comparative evaluation of flexural strength of commercially available acrylic and modified polymethylmethacrylate: an in vitro study.
abstract: OBJECTIVE
  The purpose of this study was to evaluate and compare the flexural strength of commercially available acrylic (trevalone) and modified polymethylmethacrylate (PMMA).
  
  
  METHODS
  Four groups were tested; Group 1- control group regular MMA, group 2-2% methacrylic acid, 88% MMA, group 3-16% methacrylic acid, 84% MMA group 4- 20% methacrylic acid, 80% MMA 15 resin specimens of each group were polymerized. After processing, the specimens were subjected for flexural strength testing using three point bending test in a Universal Testing Machine. All data was statistically analyzed with one-way ANOVA, differences within the groups were analyzed by Scheffe's analysis.
  
  
  RESULTS
  As the ratio of incorporated methacrylic acid to PMMA increased, the flexural strength decreased. Analysis of data revealed a significant decrease in flexural strength of specimens (p < 0.000) after incorporation of 12%, 16%, 20% methacrylic acid to heat polymerized acrylic resin, when compared with the control group. Lowest flexural strength was observed with specimens containing 20% methacrylic acid and highest flexural strength was observed with specimens containing conventional monomer without methacrylic acid.
  
  
  CONCLUSIONS
  It was observed that as the concentration of methacrylic acid in heat polymerized acrylic resin increases, the flexural strength decreases. Lowest flexural strength was observed with specimens containing 20% methacrylic acid and highest flexural strength was observed with specimens containing conventional monomer without methacrylic acid.
  
  
  CONCLUSIONS
  The major advantages of addition of methacrylic acid to polymethylmethacrylate could be for the elderly people with restricted manual dexterity or cognitive disturbances, especially for patients who do not follow an adequate denture cleansing protocol and diabetic patients who are more susceptible for denture stomatitis.
authors.affiliation: Department of Prosthodontics, People's Dental Academy, Bhopal, Madhya Pradesh, India. dr.teerthesh.jain@gmail.com
authors.forename: Teerthesh
authors.initials: T
authors.lastname: Jain
authors.forename: Naveen S
authors.initials: NS
authors.lastname: Yadav
authors.forename: Amrita
authors.initials: A
authors.lastname: Pandita
authors.forename: S M A
authors.initials: SM
authors.lastname: Feroz
authors.forename: U K
authors.initials: UK
authors.lastname: Kartika
authors.forename: Praval Pratap
authors.initials: PP
authors.lastname: Singh
mesh_terms: D003764:Dental Materials / Q000737:chemistry*; D003799:Dental Stress Analysis / Q000295:instrumentation; D055119:Elastic Modulus; D004548:Elasticity; D006358:Hot Temperature; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D020366:Methylmethacrylate / Q000737:chemistry; D008768:Methylmethacrylates / Q000737:chemistry*; D018583:Pliability; D058105:Polymerization; D019904:Polymethyl Methacrylate / Q000737:chemistry*; D013314:Stress, Mechanical; D013499:Surface Properties
chemical_list: D003764:Dental Materials; D008689:Methacrylates; D008768:Methylmethacrylates; D020366:Methylmethacrylate; C008384:methacrylic acid; C029883:Trevalon universal; D019904:Polymethyl Methacrylate