title: Histological evaluation of MTA as a root-end filling material.
abstract: OBJECTIVE
  To assess the histological response associated with grey mineral trioxide aggregate (GMTA) and zinc oxide eugenol (ZOE) as root-end filling materials in teeth where the root canals were not filled and the coronal access cavities were not restored.
  
  
  METHODS
  Periapical lesions were developed in 24 premolar teeth in three dogs. The root canals were prepared and half of them were dried, filled and the coronal access restored (closed). The remaining teeth were not root filled and no coronal restoration was placed (open). Apical root-end resections were performed 3 mm from the apex, and root-end cavities were prepared with ultrasonic tips. These were randomly filled with either ZOE or GMTA in the same number of specimens using MAPSYSTEM device. After 180 days the animals were killed and blocks of tissues removed and processed for histological examination. Periradicular tissue reaction was evaluated, including severity of inflammation and cementum formation. Statistical analysis was performed using anova analysis and Tukey's test.
  
  
  RESULTS
  A significant difference was found between the levels of inflammation in the periradicular tissues of the GMTA/closed group, compared with the ZOE/open and ZOE/closed groups (P < 0.05) but not between GMTA/closed and GMTA/open groups. Cementum formation was not found over any ZOE specimens but over MTA in all specimens. No microorganisms were found in the interface between the material and the dentinal walls.
  
  
  CONCLUSIONS
  GMTA was associated with less periapical inflammation and tissue response when used as a root-end filling material, even when no root filling or coronal restoration was present.
authors: Department of Endodontics, Araçatuba School of Dentistry, UNESP, Araçatuba, Sâo Paulo, Brazil. bernabe@foa.unesp.br
authors: P F E
authors: PF
authors: Bernabé
authors: J E
authors: JE
authors: Gomes-Filho
authors: W C
authors: WC
authors: Rocha
authors: M J
authors: MJ
authors: Nery
authors: J A
authors: JA
authors: Otoboni-Filho
authors: E
authors: E
authors: Dezan-Júnior
mesh_terms: D017607:Aluminum Compounds / Q000009:adverse effects*; D000818:Animals; D001047:Apicoectomy / Q000379:methods*; D017610:Calcium Compounds / Q000009:adverse effects*; D004285:Dogs; D004338:Drug Combinations; D008297:Male; D010087:Oxides / Q000009:adverse effects*; D010485:Periapical Periodontitis / Q000139:chemically induced / Q000473:pathology; D012387:Root Canal Filling Materials / Q000009:adverse effects*; D017640:Silicates / Q000009:adverse effects*; D015035:Zinc Oxide-Eugenol Cement / Q000009:adverse effects*
chemical_list: D017607:Aluminum Compounds; D017610:Calcium Compounds; D004338:Drug Combinations; D010087:Oxides; D012387:Root Canal Filling Materials; D017640:Silicates; D015035:Zinc Oxide-Eugenol Cement; C086631:mineral trioxide aggregate