A randomized controlled trial of endodontically treated and restored premolars

J Dent Res. 2012 Jul;91(7 Suppl):72S-78S. doi: 10.1177/0022034512447949.


This in vivo study examined the contribution of remaining coronal dentin and placement of a prefabricated (LP) or customized fiber post (ES) to the six-year survival of endodontically treated premolars. A sample of 345 patients provided 6 groups of 60 premolars each in need of endodontic treatment. Groups were classified according to the number of remaining coronal walls before abutment build-up. Within each group, teeth were allocated to one of three subgroups: (A) no post retention; (B) LP; or (C) ES (N = 20). All teeth were protected with a crown. Cox regression analysis revealed that fiber post retention significantly improved tooth survival (p < 0.001). Failure risk was lower in teeth restored with prefabricated (p = 0.001) than with customized posts (p = 0.009). Teeth with one (p = 0.004), two (p < 0.001), and three coronal walls (p < 0.001) had significantly lower failure risks than those without ferrule. Similar failure risks existed for teeth without coronal walls, regardless of the presence/absence of ferrule (p = 0.151). Regardless of the restorative procedure, the preservation of at least one coronal wall significantly reduced failure risk (ClinicalTrials.gov number CT01532947).

Trial registration: ClinicalTrials.gov NCT01532947.

Publication types

  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Bicuspid / pathology*
  • Crowns
  • Dental Abutments
  • Dental Bonding
  • Dental Prosthesis Design
  • Dental Prosthesis Retention
  • Dental Restoration Failure
  • Dentin / pathology
  • Follow-Up Studies
  • Humans
  • Post and Core Technique* / instrumentation
  • Prospective Studies
  • Root Canal Therapy
  • Tooth Fractures / etiology
  • Tooth Root / injuries
  • Tooth, Nonvital / therapy*
  • Treatment Outcome

Associated data

  • ClinicalTrials.gov/NCT01532947