title: Shock absorbability and hardness of commercially available denture teeth.
abstract: OBJECTIVE
  Composite resin teeth are more widely used than porcelain or acrylic resin teeth in the fabrication of removable dentures because of their high fracture toughness and high abrasion resistance. The purpose of this study was to evaluate the shock absorbability of commercially available artificial posterior teeth by the free drop-ball test with an accelerometer and to evaluate the Vickers hardness at the surface.
  
  
  METHODS
  The tested artificial teeth included seven composite resin teeth, one acrylic resin tooth, and one porcelain tooth. Specimens were tested 50 hours after immersion in distilled water at 37 degrees C. The impact value and Vickers hardness were measured. A one-way analysis of variance was used to analyzed the data (P = .05).
  
  
  RESULTS
  The composite resin teeth showed an intermediate impact value between that of the acrylic resin tooth and the porcelain tooth. Among the artificial teeth investigated, the porcelain tooth showed the highest impact value. A significant difference in the impact value was observed between the porcelain tooth and the composite resin and acrylic resin teeth. However, no significant difference was observed among the composite resin teeth tested. A significant correlation was found between the impact values and the Vickers hardness of the artificial teeth.
  
  
  CONCLUSIONS
  The present findings suggest that composite resin teeth and acrylic resin teeth have a higher shock absorbability than porcelain teeth.
authors.affiliation: Department of Removable Prosthodontics, Tokushima University, School of Dentistry, 3-18-15 Kuramoto-cho, Tokushima 770-8504, Japan. fumiaki@dent.tokushima-u.ac.jp
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Kawano
authors.forename: Takafumi
authors.initials: T
authors.lastname: Ohguri
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Ichikawa
authors.forename: Iwate
authors.initials: I
authors.lastname: Mizuno
authors.forename: Akira
authors.initials: A
authors.lastname: Hasegawa
mesh_terms: D000042:Absorption; D000054:Acceleration; D000180:Acrylic Resins / Q000737:chemistry; D000704:Analysis of Variance; D003188:Composite Resins / Q000737:chemistry; D003764:Dental Materials / Q000737:chemistry*; D003776:Dental Porcelain / Q000737:chemistry; D003779:Denture Design; D006244:Hardness; D006801:Humans; D007101:Immersion; D008422:Materials Testing; D008963:Molar; D013223:Statistics as Topic; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014093:Tooth, Artificial; D014867:Water / Q000737:chemistry
chemical_list: D000180:Acrylic Resins; D003188:Composite Resins; D003764:Dental Materials; D014867:Water; D003776:Dental Porcelain