title: Analysis of the secondary endodontic lesions focusing on the extraradicular microorganisms: an overview.
abstract: The present study aimed at reviewing the literature on extraradicular infections of endodontically treated teeth, summarizing the main hypotheses on etiopathogenesis and describing the most suitable techniques to identify the composition of pathogenic extraradicular microorganisms. Medline database was searched using the keywords "Apical biofilm," "extraradicular infection," "secondary endodontic lesion," "endodontic retreatment," "biofilm" either alone or combined with AND. A further hand search was performed on the main endodontic journals. The most frequent bacterial species identified in different studies and with different techniques may vary considerably. Although the presence of some species of microorganisms seems to be determinant, the true origin of extraradicular infection is still undetermined. The literature analysis showed marked differences in methodology, materials, aims, and techniques adopted, which led to highly heterogeneous outcomes. The picture emerging from this review is that extraradicular infection is likely a multifactorial disease that requires further systematic investigation using standardized techniques.
authors.affiliation: Director of Center of Research for Oral Health, Department of Biomedical, Surgical and Dental Sciences, Dental Clinic, IRCCS Galeazzi Orthopedic Institute, Universitá degli Studi di Milano, Milano, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Del Fabbro
authors.forename: Lakshman P
authors.initials: LP
authors.lastname: Samaranayake
authors.forename: Alessandra
authors.initials: A
authors.lastname: Lolato
authors.forename: Tommaso
authors.initials: T
authors.lastname: Weinstein
authors.forename: Silvio
authors.initials: S
authors.lastname: Taschieri
mesh_terms: D018441:Biofilms; D006094:Gram-Positive Bacteria / Q000145:classification; D016908:Gram-Positive Bacterial Infections / Q000175:diagnosis; D006801:Humans; D010485:Periapical Periodontitis / Q000382:microbiology*; D012008:Recurrence; D019233:Retreatment; D019553:Tooth, Nonvital / Q000382:microbiology*
keywords: extraradicular lesion; extraradicular microorganisms; molecular diagnostic techniques; scanning electron microscopy; secondary endodontic lesion