title: Effect of embedded metal reinforcements and their location on the fracture resistance of acrylic resin complete dentures.
abstract: OBJECTIVE
  This study evaluated the effect of metal reinforcement and its location on the flexural load at the proportional limit (FL-PL) and the flexural deflection of maxillary acrylic resin complete dentures.
  
  
  METHODS
  Maxillary acrylic resin complete dentures reinforced with Remanium and without reinforcement were tested. The reinforcing material was embedded in the denture base resin in the doughy state and placed (1) under the ridge lap region; (2) in the anterior region; (3) in the middle region; and (4) in the anterior and posterior regions. The FL-PL (N) and the flexural deflection (mm) at 100 N of the reinforced maxillary denture specimens were tested using a load testing machine at a 5.0 mm/min crosshead speed. The data were analyzed statistically using one-way ANOVA; Tukey's post hoc comparisons test was applied when appropriate (95% confidence level).
  
  
  RESULTS
  The FL-PL of the dentures without reinforcement (909 ± 195 N) and the dentures reinforced at the ridge lap (1094 ± 176 N) and in the middle (977 ± 215 N) regions were not significantly different (p > 0.05). The dentures reinforced in the anterior (1348 ± 205 N) and the anterior and posterior (1190 ± 191 N) regions had a higher FL-PL than the dentures without reinforcement (p < 0.05) and were not significantly different from each other (p > 0.05). The efficiency (times) of the reinforcing material on the dentures without reinforcement was 1.08 to 1.48. The flexural deflection of the dentures without reinforcement (0.133 ± 0.014 mm), the dentures reinforced at the ridge lap (0.125 ± 0.014 mm), in the anterior (0.122 ± 0.009 mm), and in the middle (0.132 ± 0.015 mm) regions were not significantly different (p > 0.05), and the dentures reinforced in the anterior and posterior (0.117 ± 0.011 mm) regions had significantly lower deflection than the dentures without reinforcement (p < 0.05).
  
  
  CONCLUSIONS
  The location of the metal reinforcement affected the fracture resistance of the maxillary acrylic resin complete dentures.
authors.affiliation: Division of Removable Prosthodontics, Fukuoka Dental College, Fukuoka, Japan.
authors.forename: Kaneyoshi
authors.initials: K
authors.lastname: Yoshida
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Shimizu
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D000537:Aluminum Oxide / Q000737:chemistry; D003722:Dental Alloys / Q000737:chemistry*; D045662:Dental Etching; D003764:Dental Materials / Q000737:chemistry*; D003799:Dental Stress Analysis / Q000295:instrumentation; D003819:Denture Bases; D003827:Denture, Complete, Upper; D055119:Elastic Modulus; D006801:Humans; D008422:Materials Testing; D018583:Pliability; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014093:Tooth, Artificial; D014867:Water / Q000737:chemistry
chemical_list: D000180:Acrylic Resins; D003722:Dental Alloys; D003764:Dental Materials; D014867:Water; C040291:Lucitone; D000537:Aluminum Oxide