Histologic Assessment of Mineral Trioxide Aggregate as a Root-End Filling in Monkeys

By Torabinejad M, Pitt Ford TR, McKendry DJ, Abedi HR, Miller DA, Kariyawasam SP

Date: 01/1997
Journal: IEJ


  • To examine the periradicular response to MTA and amalgam as root-end fillings


  • N= 12 maxillary incisors from 3 Cynomolgus monkeys
  • Rubber dam isolation. Cleaned and shaped and obturated with lateral condensation; access closed with amalgam. At 1 week, resection of apices between apical and middle thirds and 2 mm retropreparation completed. ½ of the  incisors were randomly selected to be restored with zinc-free amalgam, and ½ with MTA. Animals were given post-procedural Penicillin injection & 3 days of analgesics.
  • At 5 months, the  animals were sacrificed for histologic examination; 2 independent investigators reviewed the samples for concentration & predominant inflammatory cell type, extent and severity of inflammation, presence of bacteria and fibrous capsule, cementum deposition, and new bone formation adjacent to root end and filling material


  Dominant inflamm cell type Periradicular tissue inflam Fibrous capsule Bacteria presence (root end or canal) Cementum Bone formation
Amalgam -Lymphocytes-PMNs adjacent to amalgam 6/6 moderate to severe 6/6 0/6 6/6 over root end 0/6 over amalgam 6/6
MTA Lymphocytes 1/6 severe 0/6 0/6 6/6 over root end 5/6 over MTA (6th partially formed) 6/6

Clinical Significance:

Amalgam causes inflammation in the periradicular tissues and does not allow regeneration of dentoalveolar structures. MTA exhibits many favorable characteristics as a root-end filling material and should be chosen over amalgam, if available.