title: Prevalence of different types of accessory canals in the furcation area of third molars.
abstract: BACKGROUND
  Although there are several studies that show the prevalence and diameter of accessory root canals in the furcation area, there is a scarceness of studies that observe the trajectory and different types of cavo-interradicular canals. The aim of this study was to verify the prevalence of the different morphologic types of accessory canals in the furcation region in an attempt to show their trajectories.
  
  
  METHODS
  Forty submerged mandibular third molars were used, which were extracted and decalcified so that the microtomy procedure in the mesio-distal axial plane could be performed, obtaining semiserial sections with thicknesses of 5 microm. The sections were stained with hematoxylin and eosin and observed under optical microscopy.
  
  
  RESULTS
  All of the morphologic types were found, whereas the proper accessory canals, type-A canals, were present in 10% of the specimens. The most prevalent canals were the sealed ones (type D), with a prevalence of 87.5%, followed by the blind ones (type B), with a prevalence of 75%. The loop accessory canals (type C), observed in only 5% of the teeth, were the least prevalent ones.
  
  
  CONCLUSIONS
  Different morphologic types of accessory canals were found in the furcation area of submerged mandibular molars. The histologic method was effective to show the canal trajectories.
authors.affiliation: Department of Diagnosis and Surgery, School of Dentistry, State University of São Paulo, Araraquara, São Paulo, Brazil. elizangelazusa@bol.com.br
authors.forename: Elizangela P
authors.initials: EP
authors.lastname: Zuza
authors.forename: Benedicto E C
authors.initials: BE
authors.lastname: Toledo
authors.forename: Sebastião
authors.initials: S
authors.lastname: Hetem
authors.forename: Luis C
authors.initials: LC
authors.lastname: Spolidório
authors.forename: Ary J D
authors.initials: AJ
authors.lastname: Mendes
authors.forename: Elizabeth P
authors.initials: EP
authors.lastname: Rosetti
mesh_terms: D004396:Coloring Agents; D003648:Decalcification Technique; D003786:Dental Pulp Cavity / Q000002:abnormalities / Q000473:pathology*; D006801:Humans; D008867:Microtomy; D008964:Molar, Third / Q000473:pathology*; D016612:Paraffin Embedding; D014092:Tooth Root / Q000473:pathology*
chemical_list: D004396:Coloring Agents