title: The biomechanical role of periodontal ligament in bonded and replanted vertically fractured teeth under cyclic biting forces.
abstract: After teeth are replanted, there are two possible healing responses: periodontal ligament healing or ankylosis with subsequent replacement resorption. The purpose of this study was to compare the fatigue resistance of vertically fractured teeth after bonding the fragments under conditions simulating both healing modes. Thirty-two human premolars were vertically fractured and the fragments were bonded together with Super-Bond C&B. They were then randomly distributed into four groups (BP, CP, CA, BA). The BP and CP groups were used to investigate the periodontal ligament healing mode whilst the BA and CA groups simulated ankylosis. All teeth had root canal treatment performed. Metal crowns were constructed for the CP and CA groups. The BP and BA groups only had composite resin restorations in the access cavities. All specimens were subjected to a 260 N load at 4 Hz until failure of the bond or until 2 × 10⁶ cycles had been reached if no fracture occurred. Cracks were detected by stereomicroscope imaging and also assessed via dye penetration tests. Finally, interfaces of the resin luting agent were examined by scanning electron microscope. The results confirmed that the fatigue resistance was higher in the groups with simulated periodontal ligament healing. Periodontal reattachment showed important biomechanical role in bonded and replanted vertically fractured teeth.
authors.affiliation: Department of Endodontics, Institute and Hospital of Stomatology, Nanjing University Medical School, Nanjing, China.
authors.forename: Ya-Nan
authors.initials: YN
authors.lastname: Zhu
authors.affiliation: Department of Endodontics, Institute and Hospital of Stomatology, Nanjing University Medical School, Nanjing, China.
authors.forename: Wei-Dong
authors.initials: WD
authors.lastname: Yang
authors.affiliation: Department of Endodontics, School of Dentistry, The University of Western Australia, Perth, Australia.
authors.forename: Paul V
authors.initials: PV
authors.lastname: Abbott
authors.affiliation: Department of Adult Dental Care, School of Clinical Dentistry, The University of Sheffield, Sheffield, UK.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Martin
authors.affiliation: Department of Prothodontics, Institute and Hospital of Stomatology, Nanjing University Medical School, Nanjing, China.
authors.forename: Wen-Jia
authors.initials: WJ
authors.lastname: Wei
authors.affiliation: Department of Oral Medicine, Institute and Hospital of Stomatology, Nanjing University Medical School, Nanjing, China.
authors.forename: Jing-Jing
authors.initials: JJ
authors.lastname: Li
authors.affiliation: Department of Endodontics, The School and Hospital of Stomatology, Wuhan University, Wuhan, China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Department of Oral Medicine, Institute and Hospital of Stomatology, Nanjing University Medical School, Nanjing, China.
authors.forename: Wen-Mei
authors.initials: WM
authors.lastname: Wang
mesh_terms: D001696:Biomechanical Phenomena; D006801:Humans; D008855:Microscopy, Electron, Scanning; D010513:Periodontal Ligament / Q000502:physiology*; D013314:Stress, Mechanical; D014082:Tooth Fractures / Q000503:physiopathology* / Q000628:therapy*; D014090:Tooth Replantation