title: Effect of post type and restorative techniques on the strain and fracture resistance of flared incisor roots.
abstract: Restoring flared endodontically treated teeth continues to be a challenge for clinicians. This study evaluated the effect of post types and restorative techniques on the strain, fracture resistance, and fracture mode of incisors with weakened roots. One hundred five endodontically treated bovine incisors roots (15 mm) were divided into 7 groups (n=15). The two control groups were (C) intact roots restored with Cpc (cast posts and core) or Gfp (glass fiber posts). The five experimental groups were (F) flared roots restored with GfpAp (Gfp associated with accessory glass fiber posts), GfpRc (anatomic Gfp, relined with composite resin), and GfpRcAp (anatomized Gfp with resin and accessory glass fiber posts). All teeth were restored with metal crowns. Mechanical fatigue was performed with 3x10(5)/50 N. Specimens were loaded at 45º, and the strain values (μS) were obtained on root buccal and proximal surfaces. Following that, the fracture resistance (N) was measured. One-way ANOVA and Tukey's HSD tests (α=0.05) were applied, and failure mode was checked. No significant difference in strain values among the groups was found. Cpc presented lower fracture resistance and more catastrophic failures in flared roots. Gfp associated with composite resin or accessory glass fiber posts seems to be an effective method to improve the biomechanical behavior of flared roots.
authors.affiliation: Biomechanical Research Group, Department of Operative Dentistry and Dental Materials, Dental School, UFU - Federal University of Uberlândia, MG, Brazil.
authors.forename: Gisele Rodrigues da
authors.initials: GR
authors.lastname: Silva
authors.forename: Paulo César de Freitas
authors.initials: PC
authors.lastname: Santos-Filho
authors.forename: Paulo Cézar
authors.initials: PC
authors.lastname: Simamoto-Júnior
authors.forename: Luis Roberto Marcondes
authors.initials: LR
authors.lastname: Martins
authors.forename: Adérito Soares da
authors.initials: AS
authors.lastname: Mota
authors.forename: Carlos José
authors.initials: CJ
authors.lastname: Soares
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D002417:Cattle; D002858:Chromium Alloys / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D003442:Crowns; D003764:Dental Materials / Q000737:chemistry; D017267:Dental Prosthesis Design; D003786:Dental Pulp Cavity / Q000473:pathology; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis / Q000295:instrumentation; D003804:Dentin / Q000473:pathology; D017220:Dentin-Bonding Agents / Q000737:chemistry; D004853:Epoxy Resins / Q000737:chemistry; D005898:Glass / Q000737:chemistry; D007180:Incisor / Q000473:pathology / Q000503:physiopathology*; D011176:Post and Core Technique / Q000295:instrumentation*; D011897:Random Allocation; D019279:Resin Cements / Q000737:chemistry; D018915:Root Canal Preparation / Q000379:methods; D012821:Silanes / Q000737:chemistry; D013314:Stress, Mechanical; D014082:Tooth Fractures / Q000145:classification / Q000503:physiopathology*; D014092:Tooth Root / Q000473:pathology / Q000503:physiopathology*; D019553:Tooth, Nonvital / Q000628:therapy*
chemical_list: D002858:Chromium Alloys; D003188:Composite Resins; D003764:Dental Materials; D017220:Dentin-Bonding Agents; D004853:Epoxy Resins; D019279:Resin Cements; D012821:Silanes; C009753:fiberglass