title: The effects of therapeutic x-ray doses on mechanical, chemical and physical properties of poly methyl methacrylate.
abstract: OBJECTIVE
  The aim of this study was to investigate the effect of radiation doses very close to the human dose for oral cancers on mechanical, chemical and physical properties for poly methyl-methacrylate (PMMA).
  
  
  METHODS
  PMMA samples were divided into four different groups: no irradiated group, 25-Gy irradiated group, 50-Gy irradiated group and 75-Gy irradiated group. Each group contained nine samples. After 24 h, a three-point loading test was applied to each PMMA groups. The transverse strength and the elastic modulus were calculated using the test results. The results were analyzed statistically by using one-way analysis of variance. The structural characterizations of the PMMA samples were carried out by a Fourier Transform Infrared (FTIR) spectrophotometer to evaluate the chemical structure differences.
  
  
  RESULTS
  The transverse strength values of 25-Gy, 50-Gy and 75-Gy radiation groups were significantly higher than that of the no radiation group (p < 0.05). There was no significant difference among the elastic modulus values of the study groups (p > 0.05). The FTIR findings demonstrated that the irradiation process did not change the chemical structure of the PMMA polymeric materials.
  
  
  CONCLUSIONS
  The therapeutic radiation doses increase the mechanical properties of the PMMA; however, the chemical and structural properties have no effect. When the findings of this study are taken into account, it can be said that patients can wear dentures during the radiotherapy.
authors.affiliation: Department of Prosthetic Dentistry, Cumhuriyet University School of Dentistry, Sivas, Turkey.
authors.forename: Derya Ozdemir
authors.initials: DO
authors.lastname: Dogan
authors.forename: Yıldıray
authors.initials: Y
authors.lastname: Ozguven
authors.forename: Gulderen
authors.initials: G
authors.lastname: Karakus
authors.forename: Onur
authors.initials: O
authors.lastname: Sahin
authors.forename: Nilufer Tulin
authors.initials: NT
authors.lastname: Polat
authors.forename: Birsen
authors.initials: B
authors.lastname: Yucel
authors.forename: Mansur
authors.initials: M
authors.lastname: Dogan
mesh_terms: D000704:Analysis of Variance; D003799:Dental Stress Analysis; D004307:Dose-Response Relationship, Radiation; D055119:Elastic Modulus / Q000528:radiation effects; D006801:Humans; D008422:Materials Testing; D019904:Polymethyl Methacrylate / Q000528:radiation effects*; D011879:Radiotherapy Dosage; D017550:Spectroscopy, Fourier Transform Infrared; D013718:Tensile Strength / Q000528:radiation effects
chemical_list: D019904:Polymethyl Methacrylate