title: Sealing ability of three fiber dowel systems.
abstract: OBJECTIVE
  To study the sealing ability of two new fiber dowel systems.
  
  
  METHODS
  Thirty-six extracted single-rooted teeth were endodontically treated and randomly assigned to two new fiber dowel systems and a control group: (1) an E-glass-based dowel, everStick-POST, cemented with ParaCem Universal DC resin cement (EV); (2) a glass-fiber dowel, RelyX Fiber Post, cemented with RelyX Unicem self-adhesive resin cement (RX). The control group was restored with a glass-fiber dowel, ParaPost Fiber Lux, cemented with ParaCem Universal DC resin cement (PP). The roots were isolated and immersed in a 50 wt% ammoniacal silver nitrate solution for 24 hours followed by 8 hours in a photo-developing solution. The roots were sectioned in 1-mm-thick disks perpendicular to the long axis of the root. The specimens were processed for backscattered FESEM observation. For each tooth, the depth of silver infiltration into the root canal was measured by ranks from 0 to 8. For each disk, silver infiltration was measured as the percentage of leakage around the adhesive interface. Data were analyzed with Kruskal-Wallis nonparametric tests at a significance level of 95%.
  
  
  RESULTS
  When the silver infiltration was computed from the coronal to the apical aspects of the root, RX resulted in the lowest degree of silver infiltration, but not statistically different from that of EV (p < 0.148). RX, however, resulted in a lower depth of silver infiltration than the control group PP at p < 0.023. EV resulted in a statistically similar depth of penetration to PP (p= 0.492). Although the total mean percentage of silver infiltration at the dentin-resin cement interface was statistically similar for all groups (p= 0.632), EV resulted in the greater number of disks with silver infiltration (23 out of 96), followed by PP (21 out of 96) and RX (14 out of 96). None of the specimens showed leakage around the dowel-resin cement interface.
  
  
  CONCLUSIONS
  The use of the E-glass dowels in EV did not improve the root-wall sealing ability compared with the control group PP. The system RX, which uses a new simplified self-adhesive protocol, resulted in a lower depth of silver infiltration than the control group PP.
authors.affiliation: Department of Removable Prosthodontics, University of Lisbon School of Dentistry, Lisbon, Portugal.
authors.forename: Virgínia
authors.initials: V
authors.lastname: Santos
authors.forename: Jorge
authors.initials: J
authors.lastname: Perdigão
authors.forename: George
authors.initials: G
authors.lastname: Gomes
authors.forename: Ana Luísa
authors.initials: AL
authors.lastname: Silva
mesh_terms: D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding / Q000379:methods*; D003738:Dental Cements / Q000737:chemistry*; D003763:Dental Leakage / Q000517:prevention & control*; D018772:Dental Marginal Adaptation; D017267:Dental Prosthesis Design; D003786:Dental Pulp Cavity; D019232:Dental Restoration Failure; D006801:Humans; D011176:Post and Core Technique / Q000295:instrumentation*; D018709:Statistics, Nonparametric
chemical_list: D003188:Composite Resins; D003738:Dental Cements