title: Influence of white and gray endodontic posts on color changes of tooth roots, composite cores, and all-ceramic crowns.
abstract: OBJECTIVE
  To evaluate whether post materials affect the color of roots, composite cores, and all-ceramic crowns.
  
  
  METHODS
  Forty extracted human incisors were divided into four groups. White posts made of zirconia (Zi) or glass fiber (Gf) and gray posts made of titanium (Ti) or carbon fiber (Cf) were randomly assigned to the roots. Composite cores and glass-ceramic crowns were made. The color of the roots, cores, and crowns was captured (Spectroshade). The mean color difference (mDeltaE) among the groups was calculated for the following comparisons: A--root: empty root versus post and core; B--root: post and core with and without cement; C--core: white versus gray posts and cores; D--lower third of crown versus original ceramic ingot; E--center of crown versus ingot. Statistical analysis was performed by ANOVA, Kruskal-Wallis, and Sheffe tests.
  
  
  RESULTS
  White, as well as gray posts, induced little changes of the root color (A, B). Gray posts led to a significant discoloration of the cores (C: mDeltaEZi 2.0+/-0.7, mDeltaEGf 1.5+/-0.6, mDeltaETi 12.9+/-5.9, mDeltaECf 11.2+/-5.3; P<.0001, Kruskal-Wallis) resulting in a grayish discoloration of the crowns' lower thirds (D: mDeltaEZi 5.7+/-0.8, mDeltaEGf 6.0+/-1.2, mDeltaETi 3.5+/-1.1, mDeltaECf 3.9+/-0.9; P<.0001, Kruskal-Wallis). In the center of the crowns, all posts and cores induced a similar color difference (E).
  
  
  CONCLUSIONS
  A grayish gingival shadowing cannot be reduced with white posts. In combination with glass-ceramic crowns, white posts and cores are esthetically beneficial.
authors.affiliation: Department of Fixed and Removable Prosthodontics and Dental Material Science, Center for Dental and Oral Medicine, University of Zurich, Zurich, Switzerland. Irena.sailer@zzmk.uzh.ch
authors.forename: Irena
authors.initials: I
authors.lastname: Sailer
authors.forename: Andrea
authors.initials: A
authors.lastname: Thoma
authors.forename: Ameen
authors.initials: A
authors.lastname: Khraisat
authors.forename: Ronald E
authors.initials: RE
authors.lastname: Jung
authors.forename: Christoph H F
authors.initials: CH
authors.lastname: Hämmerle
mesh_terms: D000704:Analysis of Variance; D002244:Carbon; D000077482:Carbon Fiber; D003116:Color; D003188:Composite Resins; D003442:Crowns; D003776:Dental Porcelain; D005898:Glass; D006801:Humans; D007180:Incisor; D011176:Post and Core Technique / Q000009:adverse effects*; D017797:Prosthesis Coloring; D013053:Spectrophotometry; D018709:Statistics, Nonparametric; D014025:Titanium; D014075:Tooth Discoloration / Q000209:etiology*; D014092:Tooth Root / Q000473:pathology
chemical_list: D000077482:Carbon Fiber; D003188:Composite Resins; C009753:fiberglass; D003776:Dental Porcelain; D002244:Carbon; D014025:Titanium