title: Effect of post-retained composite restoration of MOD preparations on the fracture resistance of endodontically treated teeth.
abstract: OBJECTIVE
  The present study aimed to compare the fracture resistance and failure patterns of endodontically treated premolars with MOD preparations restored using different material combinations. The null hypothesis postulated that there was no association between the fracture resistance of endodontically treated premolars and the resin composite materials or the post-and-core system used to build up the restorations.
  
  
  METHODS
  Eighty single-rooted maxillary premolars were used. After endodontic treatment and preparation of MOD preparations, 8 groups of 10 samples each were created, using the following material combinations: group 1 (control), flowable and microhybrid resin composites; group 2, flowable A; group 3, flowable B; group 4, microhybrid resin A; group 5, microhybrid resin B; group 6, flowable B + microhybrid resin B; group 7, flowable A + microhybrid resin A + post A; group 8, flowable B + microhybrid resin B + post B. Mechanical static fracture tests were performed loading the specimens till fracture.
  
  
  RESULTS
  The mean failure loads (N) were 502 (control), 470 (group 7), 445 (group 8), 441 (group 6), 405 (group 5), 364 (group 4), 317 (group 2), and 302 (group 3). Statistically significant differences were found between groups 1 vs 2, 1 vs 3, and 3 vs 7 (p < 0.05).
  
  
  CONCLUSIONS
  The fracture resistance of endodontically treated premolars with MOD preparations was enhanced by the use of the sandwich technique. The samples restored with posts predominantly showed restorable fractures, while teeth restored without posts mostly displayed unrestorable failures.
authors: Department of Dental Materials and Restorative Dentistry, University of Siena, Policlinico Le Scotte, Siena, Italy.
authors: Roberto
authors: R
authors: Sorrentino
authors: Ziad
authors: Z
authors: Salameh
authors: Fernando
authors: F
authors: Zarone
authors: Franklin R
authors: FR
authors: Tay
authors: Marco
authors: M
authors: Ferrari
mesh_terms: D000134:Acid Etching, Dental; D017609:Barium Compounds / Q000737:chemistry; D001641:Bicuspid; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D003764:Dental Materials / Q000737:chemistry; D019232:Dental Restoration Failure; D003793:Dental Restoration, Permanent / Q000295:instrumentation / Q000379:methods*; D017220:Dentin-Bonding Agents / Q000737:chemistry; D005898:Glass / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D011109:Polymethacrylic Acids / Q000737:chemistry; D011176:Post and Core Technique / Q000295:instrumentation; D019279:Resin Cements / Q000737:chemistry; D018915:Root Canal Preparation; D012822:Silicon Dioxide / Q000737:chemistry; D013314:Stress, Mechanical; D014082:Tooth Fractures / Q000503:physiopathology*; D019553:Tooth, Nonvital / Q000503:physiopathology / Q000628:therapy*
chemical_list: C121035:Aeliteflo; D017609:Barium Compounds; C433205:Calibra; D003188:Composite Resins; D003764:Dental Materials; D017220:Dentin-Bonding Agents; C466112:Esthet-X; D011109:Polymethacrylic Acids; C425843:Prime and Bond NT; D019279:Resin Cements; C121818:Tetric ceram; C009753:fiberglass; C111840:flowable hybrid composite; C452226:tetric flow composite resin; D017438:Bisphenol A-Glycidyl Methacrylate; D012822:Silicon Dioxide