title: Fracture resistance of simulated immature maxillary anterior teeth restored with fiber posts and composite to varying depths.
abstract: BACKGROUND
  Traumatized immature teeth present a unique challenge during treatment, both endodontically as well as restoratively. Hence, the purpose of this study is to evaluate the type and depth of restoration that would be effective in simulated immature maxillary anterior teeth in terms of fracture resistance and mode of failure.
  
  
  METHODS
  Seventy-five extracted human maxillary anterior teeth were used in this study that was standardized to a length of 13 mm. Instrumentation of the canals was performed after which a Peezo no. 6 was taken 1 mm past the apex to simulate an incompletely formed root. MTA apexification was simulated after which all the teeth were mounted and a 3-mm-diameter engineering twist drill extended the preparation 3 and 7 mm below the facial cemento-enamel junction (CEJ) to simulate Cvek's stage 3. These teeth were divided into seven different groups: Group 1: Negative control: intact teeth; Group 2: Positive control: 3 mm, no restoration; Group 3: Positive control: 7 mm, no restoration; Group 4: 3-mm composite; Group 5: 3-mm quartz fiber post; Group 6: 7-mm composite; Group 7: 7-mm quartz fiber post. Fracture resistance was performed at 130° to the long axis of the tooth with a chisel-shaped tip at the cingulum with a cross-head speed of 5 mm min(-1) , and the maximum load at which the fracture occurred was recorded.
  
  
  RESULTS
  Group 1 that was the negative control showed the highest fracture resistance. Among the experimental groups, 4 and 5 showed the highest fracture resistance, which were significantly different from groups 6 and 7, respectively.
  
  
  CONCLUSIONS
  Within the limitations of this in vitro study, it can be concluded that using either dual-cure composite or a quartz fiber post with composite resin to a depth of 3 mm would significantly strengthen the roots in immature teeth.
authors.affiliation: Department of Endodontics, University of Washington, Seattle, WA, USA.
authors.forename: Brandon
authors.initials: B
authors.lastname: Seto
authors.forename: Kwok-Hung
authors.initials: KH
authors.lastname: Chung
authors.forename: James
authors.initials: J
authors.lastname: Johnson
authors.forename: Avina
authors.initials: A
authors.lastname: Paranjpe
mesh_terms: D006801:Humans; D008437:Maxilla / Q000473:pathology*; D011176:Post and Core Technique; D014082:Tooth Fractures / Q000601:surgery*