title: A temporary filling material used for coronal sealing during endodontic treatment may cause tooth fractures in large Class II cavities in vitro.
abstract: OBJECTIVE
  To investigate the use of a zinc oxide/zinc sulphate-based cement (Coltosol(®) F, Coltène Whaledent, Cuyahoga Falls, OH, USA) as a temporary filling material during multiple-visit root canal treatments and the occurrence of cracks within the filling material or the tooth.
  
  
  METHODS
  Root canals of one hundred and twenty-two extracted human molars were prepared using ProTaper instruments up to size F2. After root canal preparation, standardized mesial-occlusal-distal cavities were prepared. The buccal-lingual/palatal width of the cavities was 4.5 mm), so that the remaining cavity walls had a mean thickness of 3.5 mm. Teeth were checked for cracks and fracture lines using a stereomicroscope with 10× magnification. A calcium hydroxide slurry was used as an intracanal dressing. The teeth were divided into three groups. In the Coltosol group, the cavity was filled with Coltosol(®) F. In the Coltosol-Clearfil group, a 2-mm layer of Coltosol(®) F was placed into the coronal pulp chamber, the remaining cavity was filled with Clearfil(™) . In the Clearfil group, a foam pellet was placed onto the orifices of the root canals, the remaining cavity was filled with Clearfil(™) . In the control group, the cavities were left without any filling material. The teeth were stored in water at 37 °C for 14 days and examined every 24 h under a stereomicroscope for fracture lines occurring on the tooth surface or in the filling material.
  
  
  RESULTS
  In the Coltosol group, fractures within the filling material were observed in 28 (85%) of 33 teeth. 13 (39%) teeth had tooth fractures. Amongst these teeth, 8 (61%) had root fractures, 1 (8%) had a crown fracture and 4 (31%) had a root-crown fracture.
  
  
  CONCLUSIONS
  Coltosol(®) F, when used alone as a restorative material, led to tooth fractures in Class II cavities in teeth undergoing root canal treatment. Tooth fractures may occur 4 days after placement of the filling.
authors.affiliation: Department of Operative Dentistry and Periodontology, University of Freiburg - Medical Center, Freiburg, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Tennert
authors.forename: M
authors.initials: M
authors.lastname: Eismann
authors.forename: F
authors.initials: F
authors.lastname: Goetz
authors.forename: J P
authors.initials: JP
authors.lastname: Woelber
authors.forename: E
authors.initials: E
authors.lastname: Hellwig
authors.forename: O
authors.initials: O
authors.lastname: Polydorou
mesh_terms: D002126:Calcium Hydroxide / Q000737:chemistry; D002133:Calcium Sulfate / Q000737:chemistry*; D003188:Composite Resins / Q000737:chemistry; D003794:Dental Restoration, Temporary; D006801:Humans; D066298:In Vitro Techniques; D008963:Molar; D019279:Resin Cements / Q000737:chemistry; D012387:Root Canal Filling Materials / Q000737:chemistry*; D018915:Root Canal Preparation / Q000379:methods*; D014082:Tooth Fractures / Q000209:etiology*; D019287:Zinc Sulfate / Q000737:chemistry*
chemical_list: C029849:Clearfil Bonding Agent; C469237:Clearfil Core; C504942:Coltosol F; D003188:Composite Resins; D019279:Resin Cements; D012387:Root Canal Filling Materials; D019287:Zinc Sulfate; D002126:Calcium Hydroxide; D002133:Calcium Sulfate
keywords: coltosol; coronal seal; cracked tooth; endodontic treatment; temporary filling; tooth fracture