title: In vitro assessment of the tooth staining potential of endodontic materials in a bovine tooth model.
abstract: OBJECTIVE
  Traumatized teeth requiring endodontic intervention may discolor as a result of the treatment performed. Thus, the aim was to investigate the discoloration potential of different endodontic cements, dressings, and irrigants used in dental traumatology.
  
  
  METHODS
  Cylindrical cavities were prepared in 330 bovine enamel-dentine blocks (10 × 10 × 3.5 mm), leaving 2 mm of enamel and dentine on the labial side. The specimens were randomly assigned to 22 groups (n = 15). The cavities were filled with a range of endodontic materials, sealed with composite and stored in physiological saline. The color of the labial enamel surface was measured with a spectrophotometer at 7 time intervals: before (T0) and after the placement of the test material (T1 = baseline), after 1 week (T2), 1 month (T3), 3 months (T4), 6 months (T5), and 12 months (T6). The color difference values (ΔE) were calculated and further analyzed by anova and the Tukey-Kramer post hoc test (α = 0.05).
  
  
  RESULTS
  After 12 months, significant staining was observed among the endodontic cements only in the Portland cement group with additional bismuth oxide (H-MED PC BiOx; ΔE 22.2). Specimens with other commercially available calcium silicate cements containing bismuth oxide were not significantly discolored. All specimens with endodontic dressings and irrigants were color stable except the tested triple antibiotic paste (M-TreVitaMix; ΔE 14.9) and the double antibiotic paste (N-BiMix; ΔE 14.9). Both mixtures did not contain tetracycline derivatives.
  
  
  CONCLUSIONS
  The presence of bismuth oxide in calcium silicate cements was not shown to be a reliable predictor for tooth discoloration. Antibiotic pastes without tetracycline derivatives do not guarantee the color stability of teeth.
authors.affiliation: Department of Periodontology, Endodontology and Cariology, University Center for Dental Medicine, University of Basel, Basel, Switzerland.
authors.forename: Christian A
authors.initials: CA
authors.lastname: Dettwiler
authors.affiliation: Department of Periodontology, Endodontology and Cariology, University Center for Dental Medicine, University of Basel, Basel, Switzerland.
authors.forename: Mirella
authors.initials: M
authors.lastname: Walter
authors.affiliation: Department of Periodontology, Endodontology and Cariology, University Center for Dental Medicine, University of Basel, Basel, Switzerland.
authors.forename: Lucia K
authors.initials: LK
authors.lastname: Zaugg
authors.affiliation: Department of Reconstructive Dentistry and Temporomandibular Disorders, University Center for Dental Medicine, University of Basel, Basel, Switzerland.
authors.forename: Patrik
authors.initials: P
authors.lastname: Lenherr
authors.affiliation: Department of Periodontology, Endodontology and Cariology, University Center for Dental Medicine, University of Basel, Basel, Switzerland.
authors.forename: Roland
authors.initials: R
authors.lastname: Weiger
authors.affiliation: Department of Conservative Dentistry and Periodontology, University of Würzburg, Würzburg, Germany.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Krastl
mesh_terms: D000818:Animals; D002417:Cattle; D003116:Color; D003804:Dentin; D008422:Materials Testing; D011897:Random Allocation; D012387:Root Canal Filling Materials; D013194:Staining and Labeling; D014070:Tooth; D014075:Tooth Discoloration
chemical_list: D012387:Root Canal Filling Materials
keywords: Portland cement; endodontic irrigants; endodontic materials; endodontic medicaments; mineral trioxide aggregate; tooth discoloration