title: Chewing efficiency and occlusal forces in PMMA, acetal and polyamide removable partial denture wearers.
abstract: OBJECTIVE
  Thermoplastic materials, such as acetal (AC) and polyamide (PA), constitute an alternative to polymethyl methacrylate (PMMA) based resins as the materials for removable partial dentures. However, none of the previous studies compared chewing efficiency and occlusal forces in the wearers of dentures made of various materials. Therefore, the aim of this study was to determine and compare the chewing efficiency and occlusal forces in PMMA, PA and AC RPDs' wearers. The hypothesis was that the type of denture base material shows a significant effect on chewing efficiency (expressed as a degree of food fragmentation) and occlusal force.
  
  
  METHODS
  The experiment included the group of 30 patients using removable partial dentures. The dentures made of PMMA, acetal and polyamide were tested in each patient. Each denture was worn for 90 days, with a random sequence of the denture manufacturing and insertion. After 7, 30 and 90 days of each denture wear, chewing efficiency coefficient was determined with the aid of a sieving method, and occlusal force was measured with a dynamometer.
  
  
  RESULTS
  The use of dentures made of PMMA or acetal was reflected by a marked increase in chewing efficiency and occlusal force. None of these parameters changed significantly with the time of denture wear. Moreover, no significant correlation was found between chewing efficiency and occlusal forces.
  
  
  CONCLUSIONS
  Denture base material exerts significant effects on the degree of food fragmentation and the level of occlusal forces. The use of dentures and clasps made of materials with lower modulus of elasticity is associated with lower chewing efficiency and lower occlusal forces.
authors.affiliation: Chair of Prosthetics and Dental Materials, Department of Dental Prosthetics, Medical University of Silesia in Katowice, School of Medicine with the Division of Dentistry in Zabrze, Zabrze, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Macura-Karbownik
authors.affiliation: Institute of Engineering Materials and Biomaterials, Faculty of Mechanical Engineering, Silesian University of Technology, Gliwice, Poland.
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Chladek
authors.affiliation: Institute of Engineering Materials and Biomaterials, Faculty of Mechanical Engineering, Silesian University of Technology, Gliwice, Poland.
authors.forename: Jarosław
authors.initials: J
authors.lastname: Żmudzki
authors.affiliation: Chair of Prosthetics and Dental Materials, Department of Dental Prosthetics, Medical University of Silesia in Katowice, School of Medicine with the Division of Dentistry in Zabrze, Zabrze, Poland.
authors.forename: Jacek
authors.initials: J
authors.lastname: Kasperski
mesh_terms: D000080:Acetals / Q000494:pharmacology*; D000328:Adult; D001732:Bite Force; D003832:Denture, Partial, Removable; D005260:Female; D006801:Humans; D008297:Male; D008409:Mastication / Q000187:drug effects*; D008875:Middle Aged; D009757:Nylons / Q000494:pharmacology*; D019904:Polymethyl Methacrylate / Q000494:pharmacology*
chemical_list: D000080:Acetals; D009757:Nylons; D019904:Polymethyl Methacrylate