title: Bacterial colonization in the apical part of extracted human teeth following root-end resection and filling: a confocal laser scanning microscopy study.
abstract: OBJECTIVE
  The purpose of this study was to evaluate Enterococcus faecalis colonization at the apical part of root canals following root-end resection and filling using confocal laser scanning microscopy (CLSM).
  
  
  METHODS
  The apical 3-mm root-ends of 55 extracted single rooted human teeth were resected, and 3-mm retrograde cavities were prepared and filled using either mineral trioxide aggregate (MTA), intermediate restorative material (IRM), or Biodentine (n = 10 each); 25 teeth served as controls. The roots were placed in an experimental model, sterilized, and coronally filled with E. faecalis bacterial suspension for 21 days. Then, the apical 3-mm segments were cut to get two slabs (coronal and apical). The slabs were stained using LIVE/DEAD BacLight Bacterial Viability Kit and evaluated using CLSM.
  
  
  RESULTS
  The fluorescence-stained areas were larger in the bucco-lingual directions compared with the mesio-distal directions (p < 0.05). The mean and maximal depths of bacterial colonization into the dentinal tubules were 755 and 1643 μm, respectively, with no differences between the root-end filling materials (p > 0.05). However, more live bacteria were found in the MTA group in comparison to IRM and Biodentine groups (p < 0.05).
  
  
  CONCLUSIONS
  CLSM can be used to histologically demonstrate bacterial root-end colonization following root-end filling. This colonization at the filling-dentine interfaces and deeper into the dentinal tubules may be inhomogeneous, favoring the bucco-lingual aspects of the root.
  
  
  CONCLUSIONS
  Following root-end resection and filling bacterial colonization may lead to inflammatory reactions at the periapical tissues; the viability of the colonized bacteria may be affected by the type of root-end filling material.
authors.affiliation: Department of Endodontology, Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, P.O. Box 39040, 6997801, Tel Aviv, Israel.
authors.forename: Igor
authors.initials: I
authors.lastname: Tsesis
authors.affiliation: Department of Endodontology, Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, P.O. Box 39040, 6997801, Tel Aviv, Israel.
authors.forename: Shlomo
authors.initials: S
authors.lastname: Elbahary
authors.affiliation: Department of Endodontology, Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, P.O. Box 39040, 6997801, Tel Aviv, Israel.
authors.forename: Nuphar Blau
authors.initials: NB
authors.lastname: Venezia
authors.affiliation: Department of Endodontology, Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, P.O. Box 39040, 6997801, Tel Aviv, Israel. Dr.eyalrosen@gmail.com.
authors.forename: Eyal
authors.initials: E
authors.lastname: Rosen
mesh_terms: D017607:Aluminum Compounds; D017610:Calcium Compounds; D015169:Colony Count, Microbial; D003786:Dental Pulp Cavity / Q000382:microbiology*; D003804:Dentin / Q000382:microbiology*; D004338:Drug Combinations; D013293:Enterococcus faecalis; D006801:Humans; D066298:In Vitro Techniques; D018613:Microscopy, Confocal; D010087:Oxides; D012387:Root Canal Filling Materials; D012390:Root Canal Therapy; D017640:Silicates; D019227:Tooth Apex / Q000382:microbiology*
chemical_list: D017607:Aluminum Compounds; D017610:Calcium Compounds; D004338:Drug Combinations; D010087:Oxides; D012387:Root Canal Filling Materials; D017640:Silicates; C086631:mineral trioxide aggregate
keywords: Bacterial colonization; Confocal laser scanning microscopy; Endodontic surgery; Enterococcus faecalis; Root-end filling