title: Influence of masticatory fatigue on the fracture resistance of the pulpless teeth restored with quartz-fiber post-core and crown.
abstract: To investigate whether masticatory fatigue affects the fracture resistance and pattern of lower premolars restored with quartz-fiber post-core and full crown, 44 single rooted lower premolars recently extracted from orthodontic patients were divided into two groups of 22 each. The crowns of all teeth were removed and endodontically treated and then restored with quartz-fiber post-core and full crown. Twenty-two teeth in one group were selected randomly and circularly loaded at 45° to the long axis of the teeth of 127.4 N at a 6 Hz frequency, and the other group was not delivered to cyclic loading and considered as control. Subsequently, all teeth in two groups were continually loaded to fail at 45° to the long axis of the teeth at a crosshead speed of 1 mm⋅min(-1). The mean destructive force values were (733.88±254.99) and (869.14±280.26) N for the experimental and the control group, respectively, and no statistically significant differences were found between two groups (P>0.05). Bevel fracture and horizontal fracture in the neck of root were the major fracture mode of the specimens. Under the circumstances of this study, it seems that cyclic loading does not affect the fracture strength and pattern of the quartz-fiber post-core-crown complex.
authors.affiliation: Department of Prosthodontics, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China.
authors.forename: Er-Min
authors.initials: EM
authors.lastname: Nie
authors.forename: Xia-Yun
authors.initials: XY
authors.lastname: Chen
authors.forename: Chun-Yuan
authors.initials: CY
authors.lastname: Zhang
authors.forename: Li-Li
authors.initials: LL
authors.lastname: Qi
authors.forename: Ying-He
authors.initials: YH
authors.lastname: Huang
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D000328:Adult; D001641:Bicuspid; D001732:Bite Force; D002858:Chromium Alloys / Q000737:chemistry*; D003442:Crowns; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis / Q000295:instrumentation; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D010756:Phosphoric Acids / Q000737:chemistry; D011176:Post and Core Technique / Q000295:instrumentation*; D011791:Quartz / Q000737:chemistry*; D019279:Resin Cements / Q000737:chemistry; D013314:Stress, Mechanical; D014082:Tooth Fractures / Q000503:physiopathology; D014092:Tooth Root / Q000293:injuries; D019553:Tooth, Nonvital / Q000534:rehabilitation*
chemical_list: D002858:Chromium Alloys; C431350:Duo-Link; D008689:Methacrylates; D010756:Phosphoric Acids; D019279:Resin Cements; D011791:Quartz; C100742:All-Bond 2; C030242:phosphoric acid