Etiology of Periapical Disease

Question 1

Inflammation can be spread through what?

Answer 1

apical foramen, lateral canals, dentinal tubules

Question 2

Definition of periradicular lesions

Answer 2

products released from activated systems contribute to the inflammatory process and cause swelling, pain and tissue destruction

Question 3

Inflammatory mediators found in periapical lesions

Answer 3

Vasoactive amines (histamine, serotonin)
Bradykinin, Lysosomal enzymes, Complement fragments, Leukotrienes, Prostaglandins, Cytokines

Question 4

What is the important role of cytokines and prostaglandins

Answer 4

bone resorption

Question 5

Arachidonic Acid Metabolites

Answer 5

Cell membrane -> Arachidonic Acid -> Phospholipase A2 -> (lipooxygenase -> leukotrienes) or (cyclooxigenase -> prostaglandins or prostacyclin or thromboxane A2)

Question 6

Type 1 reactions can occur via what?

Answer 6

pushing canal contents into periradicular lesions

Question 7

Mechanical and Chemical Irritants

Answer 7

over-instrumentation, overfills gutta-percha and/or sealer, irigants, medications

Question 8

What causes endo damage?

Answer 8

severance of blood vessels, activation of coagulation pathways contribute to inflammation, activation of kinin system and complement cascade, vasoactive amines, foreign body reactions

Question 9

What are typical immunologic responses?

Answer 9

antigen (bacteria and their products), B and lymphocytes and Plasma cells, antibodies and T lymphocytes

Question 10

All the elements needed for these type of reactions have found to be present in human periradicular lesions:

Answer 10

antigens, immuno-competent cells, specific antibodies (immuno-globulins)

Question 11

Prevention of periradicular inflammation?

Answer 11

avoid pushing debris through apex, do not over-instrument, do not overmedicate, avoid pushing NaOCl through apex

Question 12

Periradicular Lesions

Answer 12

will persist until causing agent is removed (bacteria in canals)
Canals should be hermetically sealed to avoid recurrence of periradicular lesions

Question 13

Host Response

Answer 13

if defense mechanisms are compromised, infection can spread into adjacent tissues
potentially grave and even fatal consequences
immunocompromised patients

Question 14

Repair of periapical tissues

Answer 14

all periradicular tissues that have been destroyed can regenerate w/ original tissue after endodontic therapy b/c the irritating stimulus have been removed
These include alveolar bone, cementum, and periodontal ligament
Dentin will not regenerate b/c odontoblasts originate in the pulp

Question 15

Lesions of Endodontic Origin:

Answer 15

mostly etiology is from microbes, microbial toxins, and/or inflammatory mediators w/in the root canal system

Question 16

Repair of periapical tissues

Answer 16

periodontal ligament is the first tissue to be destroyed by endodontic disease
last to fully regenerate
After successful RCT, all tissues can be restored to their original state except dentin