title: Radicular Cyst: An Update of the Biological Factors Related to Lining Epithelium.
abstract: BACKGROUND
  Radicular cysts are common lesions in daily dentistry practice. However, the mechanisms related to epithelial lining formation and cavity growth are not fully understood. Therefore, the purpose of this article was to review the biological factors implicated in these process.
  
  
  METHODS
  Literature was selected through a search of PubMed electronic databases matching the following key words in the title or abstract: "cyst" OR "granuloma" OR "abscess" AND "radicular" OR "apical" OR "periapical" AND "epithelium" OR "epithelial" OR "epithelial lining." The PubMed database was searched for articles published between 1975 and 2014. Only English language was applied to the search.
  
  
  RESULTS
  The literature search yielded a total of 187 articles. After duplicate references were discarded, a subsequent search at the title and abstract level revealed 42 articles for full-text reading. The articles were categorized into 5 main subtopics: (1) cell proliferation, cell cycle, and apoptosis; (2) extracellular matrix constituents; (3) inflammatory components; (4) bone metabolic factors and; (5) others. These subtopics described the characteristics of radicular cysts focusing on the epithelial tissue effects.
  
  
  CONCLUSIONS
  Several factors from different sources (epithelial cells, stromal cells, extracellular matrix, and bone matrix) were implicated on apical cyst pathogenesis. Probably a combination of many factors involving an epithelial-stromal interaction is responsible for the sustenance and growth of apical cysts.
authors.affiliation: Basic Research Center, Dentistry School, Federal University of Rio Grande do Sul, Rio Grande do Sul, Brazil.
authors.forename: Lisiane
authors.initials: L
authors.lastname: Bernardi
authors.affiliation: Department of Oral Pathology, Dentistry School, Federal University of Rio Grande do Sul, Rio Grande do Sul, Brazil.
authors.forename: Fernanda
authors.initials: F
authors.lastname: Visioli
authors.affiliation: University Hospital Research Center, Federal University of Rio Grande do Sul, Rio Grande do Sul, Brazil.
authors.forename: Carolina
authors.initials: C
authors.lastname: Nör
authors.affiliation: Department of Oral Pathology, Dentistry School, Federal University of Rio Grande do Sul, Rio Grande do Sul, Brazil. Electronic address: pantelis@ufrgs.br.
authors.forename: Pantelis Varvaki
authors.initials: PV
authors.lastname: Rados
mesh_terms: D017209:Apoptosis; D001842:Bone and Bones / Q000378:metabolism; D002453:Cell Cycle; D049109:Cell Proliferation; D016207:Cytokines / Q000276:immunology; D004848:Epithelium / Q000276:immunology / Q000473:pathology*; D005109:Extracellular Matrix / Q000473:pathology; D006801:Humans; D007249:Inflammation / Q000473:pathology; D011842:Radicular Cyst / Q000276:immunology / Q000473:pathology*
chemical_list: D016207:Cytokines
keywords: Bone factors; epithelium; extracellular matrix; inflammation; radicular cyst