title: [Scanning electron microscope analysis of the root dentin bonding interface filled with different pastes or bonded by different program in fiber post and resin bonded repair].
abstract: OBJECTIVE
  To observe the influence of different bonding process and three different root canal sealing materials on microstructure of root canal dentin bonding interface after fiber post and resin bonding, so as to improve clinical operation steps and to optimize fiber post resin bonding effect.
  
  
  METHODS
  Fifteen human single mandibular first premolars were selected. Three were bonded with fiber posts through Relyx Unicem conventional bonding steps after filled with root canal sealing materials of zinc oxide eugenol paste (Group A), and another three were bonded through the same steps after filled with sealing materials of Vitapex (Group B). The other nine were filled with sealing materials of AH Plus, randomly divided into three groups and bonded through different steps as follows: conventional bonding steps only (Group C), etching with 35% phosphoric acid before conventional bonding steps (Group D), and etching and coating with Singlebond 2 adhesive before conventional bonding steps (Group E). After immersed in saline solution for one week, all the roots were cut into three sections of 3 mm in thickness with emery chip and numbered as crown section, middle section and tip section respectively. The samples were observed the resin protrusion in mixed layer of dentin interface and dentinal tubules by scanning electron microscopy.
  
  
  RESULTS
  We observed the resin protrusion in microstructures of the roots bonded through Relyx Unicem after filled with three different root canal sealing materials (Group A, B, C, E): most obvious in the root crown sections, middle in the root middle sections and least in the root tip sections. Differences were observed in roots filled with different sealing materials: little resin protrusion were observed in crown sections only in Group A and B, but large number of resin protrusion were found in crown and middle sections in Group C-E. Compared with Group C, no more resin protrusion were found in Group D. More and elongated resin protrusions were found in Group E.
  
  
  CONCLUSIONS
  We recommend using AH Plus as root canal sealing materials for residual crown and root needed to strengthen by fiber post. It is no need to etch before Relyx Unicem conventional bonding steps. However, coating Singlebond 2 adhesive after acid etching has the potential to increase fiber post cementation.
authors.affiliation: Department of Prosthodontics, People's Hospital in Liaocheng City, Liaocheng Shandong 252000, China. mhx13189@126.com
authors.forename: Hong-xue
authors.initials: HX
authors.lastname: Ma
authors.forename: Li-li
authors.initials: LL
authors.lastname: Shen
authors.forename: Kun
authors.initials: K
authors.lastname: Liu
authors.forename: Lin-wang
authors.initials: LW
authors.lastname: Su
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D002126:Calcium Hydroxide; D001840:Dental Bonding / Q000379:methods*; D003786:Dental Pulp Cavity / Q000648:ultrastructure; D003804:Dentin / Q000648:ultrastructure; D017220:Dentin-Bonding Agents / Q000737:chemistry; D004853:Epoxy Resins; D006801:Humans; D008334:Mandible / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D008963:Molar / Q000648:ultrastructure; D011176:Post and Core Technique; D019279:Resin Cements; D012387:Root Canal Filling Materials / Q000737:chemistry; D012828:Silicones; D014092:Tooth Root / Q000648:ultrastructure; D015035:Zinc Oxide-Eugenol Cement
chemical_list: D017220:Dentin-Bonding Agents; D004853:Epoxy Resins; C483701:Rely X Unicem; D019279:Resin Cements; D012387:Root Canal Filling Materials; D012828:Silicones; D015035:Zinc Oxide-Eugenol Cement; C029584:calcium hydroxide, iodoform, silicone oil drug combination; C534916:epoxy resin-based root canal sealer; D002126:Calcium Hydroxide