title: Microhardness of heat cure acrylic resin after treatment with disinfectants.
abstract: OBJECTIVE
  To evaluate the effect of disinfectants and distilled water on the micro-hardness of heat cure acrylic resins.
  
  
  METHODS
  The case-control study was conducted at Dr. Ishrat-ul-Ebad Khan Institute of Oral Health Sciences, Dow University of Health Sciences, and Nadirshaw Edulji Dinshaw University of Engineering and Technology, Karachi, from April to October 2011. Specimens were fabricated from heat cure acrylic resin material and they were divided into four equal groups. Group 1 was evaluated at baseline and was taken as the control group. Group 2 was immersed in distilled water for 20 minutes, Group 3 in1% sodium hypochlorite for 20 minutes, and Group 4 in 2% alkaline gluteraldehyde for 10 minutes. All specimens were polished, stored in distilled water for 24 hours prior to experiment. All the specimens were immersed twice daily for a total of 60 days after which they were tested for Vickers micro-hardness test. Statistical analysis was conducted with one-way analysis of variance and Tukey post hoc test (a=0.05).
  
  
  RESULTS
  There were 72 specimens divided into four groups of 18(25%) each. Statistically significant differences were found among all groups (p<0.0001). The storage medium had an effect on the micro-hardness of heat cure acrylic resins. Group 4 showed the most reduction in the hardness value which was followed by Group 3.
  
  
  CONCLUSIONS
  The hardness of heat cure acrylic resin was affected by disinfectants.
authors.affiliation: Dow Dental College, Dow University of Health Sciences, Karachi.
authors.forename: Faiza
authors.initials: F
authors.lastname: Amin
authors.affiliation: Hamdard University Dental Hospital, Hamdard University Karachi.
authors.forename: Abdur
authors.initials: A
authors.lastname: Rehman
authors.affiliation: Ministry of Health Kingdom of Saudi Arabia.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Abbas
mesh_terms: D000180:Acrylic Resins; D001843:Bone Cements; D016022:Case-Control Studies; D004202:Disinfectants / Q000494:pharmacology*; D005976:Glutaral / Q000494:pharmacology*; D006244:Hardness / Q000187:drug effects*; D006245:Hardness Tests; D006801:Humans; D066298:In Vitro Techniques; D019904:Polymethyl Methacrylate; D012973:Sodium Hypochlorite / Q000494:pharmacology*
chemical_list: D000180:Acrylic Resins; D001843:Bone Cements; D004202:Disinfectants; D019904:Polymethyl Methacrylate; D012973:Sodium Hypochlorite; D005976:Glutaral
keywords: Heat cure acrylic resins, Vickers micro-hardness, Disinfectants.