title: Thermogravimetric Characterization of the Microstructui Composition of Polyamide Injection Molded Denture Base Material vs Conventional Compression Molded Heat-cured Denture Base Material.
abstract: BACKGROUND
  Thermoplastic resin polymers are widely used in medicine due to their biostability and hypoallergenic properties, making them a possible alternative to poly-methylmethacrylate (PMMA). The current research examined the microstructure of a rapid injection molding system thermoplastic resin for construction of flexible denture compared with that of heat-cured PMMA.
  
  
  METHODS
  A total of 40 disk-shaped specimens (25 mm in diameter and 3 mm in thickness) were prepared and divided into two groups of 20 disks each (group I samples were of thermoplastic acrylic resin while group II was heat-cured PMMA resin).
  
  
  RESULTS
  In group I, thermogravimetric analyzer showed that increasing the temperature up to 169°C resulted in about 1.3% of the material loss, and after that the material remains thermally stable up to 200°C. Group 11 showed 2.24% weight loss at 171°C, and further weight loss (12.025%) was observed on heating to 230°C. Fourier transform infrared (FTIR) spectrophotometer analysis in the range of 400-4000 cm(-1) detected the presence of an amine group (N-H) in group I samples and the presence of methylene group attached to inorganic Si as reinforcement filler (Si-CH3).
  
  
  CONCLUSIONS
  Thermoplastic resin displayed excellent thermal stability and the absence of residual monomer within the polymerized material, suggesting its suitability for the fabrication dentures.
authors.affiliation: Associate Professor, Department of Oral and Maxillofacial Prosthodontics, Faculty of Dentistry, King Abdulaziz University, PO Box: 80209, Jeddah-21589, Kingdom of Saudi Arabia, Phone: +96626403316, e-mail: aaldharab@kau.edu.sa.
authors.forename: Ayman
authors.initials: A
authors.lastname: Al-Dharrab
authors.affiliation: Department of Oral and Maxillofacial Prosthodontics, Faculty of Dentistry, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia.
authors.forename: Lana
authors.initials: L
authors.lastname: Shinawi
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D003764:Dental Materials / Q000737:chemistry*; D003819:Denture Bases; D006358:Hot Temperature; D008422:Materials Testing; D018583:Pliability; D058105:Polymerization; D019904:Polymethyl Methacrylate / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000180:Acrylic Resins; D003764:Dental Materials; D019904:Polymethyl Methacrylate
keywords: Fourier transform infrared spectrophotometer analysis; PMMA; Polyamide; Thermogravimetric analyzer.