title: The cracked tooth: histopathologic and histobacteriologic aspects.
abstract: BACKGROUND
  The diagnosis and treatment planning of cracked teeth depend on the understanding of how cracks affect the surrounding tissues. This study evaluated the dentin and pulp conditions in teeth affected by cracks and attrition.
  
  
  METHODS
  Specimens under investigation included 12 cracked posterior teeth and 8 teeth with severe attrition. These teeth were obtained consecutively in a private practice and were extracted for reasons not related to this study. Teeth were processed for histopathologic and histobacteriologic analyses.
  
  
  RESULTS
  Cracks were histologically detected in all specimens, including the teeth with severe attrition. The cracks in all teeth were colonized by bacterial biofilms. One tooth showed several craze lines in the enamel, one of which reached dentin to a shallow depth. In some teeth, the crack ended in the dentin. Dentinal tubules were invaded by bacteria, especially when the crack extended perpendicularly into the dentin. Severe accumulations of inflammatory cells were present in the pulp zone subjacent to tubules involved with the crack. In many cases, the crack extended to the pulp, leading to reactions with intensities ranging from acute inflammation to total pulpal necrosis. Symptoms occurred in most cases in which the pulp was affected. In some cases, polymorphonuclear neutrophils were seen migrating from the pulp into the crack space and facing the bacterial biofilm located therein. Severe pulp reactions were also observed when the crack extended to the pulp chamber floor.
  
  
  CONCLUSIONS
  Cracks are always colonized with bacterial biofilms. The pulp tissue response varies according to the location, direction, and extent of the crack.
authors.affiliation: Private Practice, Cetraro, Italy. Electronic address: dricucci@libero.it.
authors.forename: Domenico
authors.initials: D
authors.lastname: Ricucci
authors.affiliation: Faculty of Dentistry, Department of Endodontics, Estácio de Sá University, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: José F
authors.initials: JF
authors.lastname: Siqueira
authors.affiliation: Private Practice, Cetraro, Italy.
authors.forename: Simona
authors.initials: S
authors.lastname: Loghin
authors.affiliation: University of Maryland School of Dentistry, Baltimore, Maryland.
authors.forename: Louis H
authors.initials: LH
authors.lastname: Berman
mesh_terms: D000328:Adult; D000368:Aged; D003387:Cracked Tooth Syndrome / Q000382:microbiology* / Q000473:pathology*; D017266:Dental Prosthesis; D005260:Female; D006801:Humans; D008297:Male; D008334:Mandible / Q000473:pathology; D008875:Middle Aged; D008963:Molar / Q000473:pathology; D010146:Pain / Q000209:etiology; D055815:Young Adult
keywords: Bacterial biofilm; cracked teeth; dentin; pulp inflammation; tooth fracture