title: A temporary filling material during endodontic treatment may cause tooth fractures in two-surface class II cavities in vitro.
abstract: OBJECTIVE
  To investigate the effect of a zinc oxide/zinc sulphate-based cement as a temporary filling material during root canal treatment on the occurrence of cracks within the filling material or the tooth.
  
  
  METHODS
  Root canals of 122 extracted human molars were prepared using ProTaper instruments. Standardized occlusal-distal cavities were prepared. After placing calcium hydroxide into the root canals, the teeth were divided randomly into four groups containing 33 specimens each. In the Coltosol group, the cavity was completely filled with Coltosol® F. In the Coltosol-Clearfil group, a 2-mm layer of Coltosol® F was placed into the apical part of the pulp chamber, and in the Clearfil group, a foam pellet was placed into the coronal pulp chamber. The remaining cavities were filled with Clearfil™. In the control group, the cavities were not restored. The teeth were stored at 37 °C for 14 days and examined every 24 h under a stereomicroscope.
  
  
  RESULTS
  Fractures of the filling and/or the tooth were only observed in the Coltosol group. All Coltosol® F restorations had cracks after 24 h. Tooth fractures were found in 25 (76 %) teeth. Among these teeth, 21 (84 %) had crown fractures, four (16 %) had root-crown fractures. All root-crown fractures were vertical.
  
  
  CONCLUSIONS
  Coltosol® F when used alone led to tooth fractures in two-surface class II cavities in teeth undergoing root canal treatment.
  
  
  CONCLUSIONS
  Coltosol® F solely used as restorative material may lead to tooth fractures in two-surface class II cavities.
authors.affiliation: Center for Dental Medicine, University Medical Center Freiburg, Department of Operative Dentistry and Periodontology, Hugstetter Str. 55, 79106, Freiburg, Germany. christian.tennert@uniklinik-freiburg.de.
authors.forename: Christian
authors.initials: C
authors.lastname: Tennert
authors.affiliation: Center for Dental Medicine, University Medical Center Freiburg, Department of Operative Dentistry and Periodontology, Hugstetter Str. 55, 79106, Freiburg, Germany.
authors.forename: Gesine Friederike
authors.initials: GF
authors.lastname: Fischer
authors.affiliation: Institute for Medical Biometry and Statistics, Center for Medical Biometry and Medical Informatics, Medical Center-University of Freiburg, Stefan-Meier-Str. 26, 79104, Freiburg, Germany.
authors.forename: Kirstin
authors.initials: K
authors.lastname: Vach
authors.affiliation: Center for Dental Medicine, University Medical Center Freiburg, Department of Operative Dentistry and Periodontology, Hugstetter Str. 55, 79106, Freiburg, Germany.
authors.forename: Johan Peter
authors.initials: JP
authors.lastname: Woelber
authors.affiliation: Center for Dental Medicine, University Medical Center Freiburg, Department of Operative Dentistry and Periodontology, Hugstetter Str. 55, 79106, Freiburg, Germany.
authors.forename: Elmar
authors.initials: E
authors.lastname: Hellwig
authors.affiliation: Center for Dental Medicine, University Medical Center Freiburg, Department of Operative Dentistry and Periodontology, Hugstetter Str. 55, 79106, Freiburg, Germany.
authors.forename: Olga
authors.initials: O
authors.lastname: Polydorou
mesh_terms: D002126:Calcium Hydroxide; D002133:Calcium Sulfate / Q000737:chemistry*; D003188:Composite Resins / Q000737:chemistry*; D003794:Dental Restoration, Temporary; D006801:Humans; D066298:In Vitro Techniques; D008963:Molar; D011897:Random Allocation; D019279:Resin Cements / Q000737:chemistry*; D012387:Root Canal Filling Materials / Q000737:chemistry*; D014082:Tooth Fractures / Q000209:etiology*; D019287:Zinc Sulfate / Q000737:chemistry*
chemical_list: C520091:CeramX; C469237:Clearfil Core; C504942:Coltosol F; D003188:Composite Resins; C469607:OptiBond FL; D019279:Resin Cements; D012387:Root Canal Filling Materials; D019287:Zinc Sulfate; D002126:Calcium Hydroxide; D002133:Calcium Sulfate
keywords: Coltosol; Cracked tooth; Endodontic treatment; Temporary cement; Temporary restoration; Tooth fracture