Purpose:
- To examine the periradicular response to MTA and amalgam as root-end fillings
Materials/Methods:
- 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
Results:
| 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.