Periradicular pathology

Question 1

What is the purpose of periapical pathology?

Answer 1

Part of host defence mechanism

Confines bacteria to root canals and prevents spread

Question 2

What is the cause of endodontic disease?

Answer 2

Bacteria

Question 3

Which microbes cause endodontic disease?

Answer 3

Mostly anaerobes (9:1 anaerobes to aerobes)

Porphyromonas and prevotella (bacteroides)

Question 4

Which bacteria is strongly implicated in cases of sinus tracts and strong odours?

Answer 4

Prevotella melaninogenica

Question 5

Which bacteria are present in extra radicular cluster formations?

Answer 5

Actinomyces israeli, propionibacterium propionicum

Question 6

Where are the microbes?

Answer 6

In almost all infections, microbes stay in the root canal

The exception is acute apical abscess

Question 7

What mostly passes apically?

Answer 7

Endotoxins

Question 8

How do microbes get in?

Answer 8

Pulpal exposure, dentinal tubules, PDL, anachoresis

Question 9

What are the different ways pulp can be exposed?

Answer 9

Trauma, vertical root fracture, pulp exposures during treatment, caries

Question 10

What is anachoresis?

Answer 10

Positive attraction of blood borne microorganisms to inflamed or necrotic tissue during bacteraemia

Question 11

What are perio/endo lesions?

Answer 11

Due to the communications between the pulpal and periodontal tissues

Question 12

What type of inflammation has evolved to discriminate pathogens from self?

Answer 12

Acute

Question 13

In acute inflammation, which cell is the first to react?

Answer 13

Neutrophils

Question 14

How is inflammation achieved in acute inflammation?

Answer 14

TLRs act on immune cells and non-immune cells to recognise pathogen associated molecular patterns (PAMPs) on the bacteria

PAMPs bind to TLR-4 to increase inflammatory mediators

Question 15

What are the three enzymatic systems involved in acute inflammation?

Answer 15

Kinin system, fibrinolytic system, complement system

Question 16

When does chronic inflammation occur?

Answer 16

• After acute inflammatory response doesn’t resolve
• Without prior acute response where immune system responds to antigen
• Infectious agent of low toxicity

Question 17

What characterises chronic inflammation?

Answer 17

Infiltration of injured tissues by leukocytes and proliferative responses

Question 18

Which lymphocytes are mostly involved in chronic inflammation?

Answer 18

CD4+ T lymphocytes

Question 19

What type of lymphocytes are the majority of circulating lymphocytes?

Answer 19

T cells

Question 20

What are the two types of T cells?

Answer 20

CD4 (t helper) and CD8 (cytotoxic/suppressor)

Question 21

What are the subdivisions of CD4 cells?

Answer 21

T helper 1, T helper 2

Question 22

What do Th1 cells do?

Answer 22

Produce IL2, interferon and activates macrophages

Question 23

What do Th2 cells do?

Answer 23

Produce interleukins and regulate production of antibodies from plasma cells

Question 24

How are macrophages activated?

Answer 24

Activated CD4 cells make interferon which primes macrophages

Primed macrophages are activated by bacterial endotoxin and other mediators

Question 25

How do activated macrophages differ from non-activated (naïve) macrophages?

Answer 25

Larger, increased chemotaxis, ability to adhere, greater ability to phagocytosis and kill microorganisms, produce bone resorptive mediators

Question 26

Consequences of chronic inflammation?

Answer 26

Damaged tissue is replaced by fibrous CT, intermittent destruction of normal tissue and healing leads to scar formation

Question 27

What factors contribute to chronic inflammation?

Answer 27

Inadequate drainage, mobility (e.g., in bony fractures), presence of necrotic tissue acts as an irritant, mechanical irritation

Question 28

What three things do you need for peri radicular pathology?

Answer 28

Bacteria, pathway to pulp, time

Question 29

What is apical periodontitis?

Answer 29

Inflammation in the periodontal tissues around apex of tooth

Question 30

Functions of apical periodontitis?

Answer 30

Defence - confines bacteria, prevents spread into adjacent bone spaces, bone resorption

Question 31

What are the three different histological presentations of apical periodontitis?

Answer 31

Granuloma, abscess, cyst

Question 32

How to distinguish between a granuloma, abscess and a cyst?

Answer 32

Cannot distinguish clinically or radiographically (only histologically) except if there is a sinus tract then it is an abscess

Question 33

What is the most common histology of apical periodontitis?

Answer 33

Granuloma

Question 34

What is a granuloma?

Answer 34

Inflammatory lesion - lymphocytes, macrophages, plasma, fibroblasts, CT ## Footnote Can be seen on tooth sometimes when extracted

Question 35

What happens histologically during abscess formation?

Answer 35

Change in cellular dynamics - dramatic increase in phagocytic activity and number of PMNs

Question 36

What is a chronic abscess?

Answer 36

Persistent, walled off chronic inflammatory tissue keeps areas of suppuration localised

Question 37

What are cysts?

Answer 37

Epithelium lined cavities that contain fluid or semi-solid material

Question 38

Where do apical cysts originate from?

Answer 38

Epithelial cell rests of Malassez

Question 39

What are the variations in cyst linings?

Answer 39

Continuous, disrupted, missing

Question 40

What is a pocket/bay cyst?

Answer 40

Inflammatory cyst, sac-like, open to and continuous with the root canal space

Question 41

What is a true cyst?

Answer 41

Within the apical granuloma, no connection between cavity and root canal surface

Question 42

Where can cysts of upper teeth originate from?

Answer 42

Maxillary sinus

Question 43

What can we do with Endodontics?

Answer 43

Reduce bacterial levels to negligible, prevent endotoxins from reaching apical tissues, entomb/incarcerate any surviving bacteria, prevent ingress of fluid ## Footnote This leads to the active lesion subsiding and bone regeneration

Question 44

What is the success rate of endodontic treatment in teeth without AP?

Answer 44

83-100%

Question 45

What is the success rate for endodontic treatment in re-treatment cases without AP?

Answer 45

89-100%

Question 46

What is the success rate of teeth with Apical periodontitis?

Answer 46

46-93%

Question 47

What is the success rate for re-treatment cases with AP?

Answer 47

56-84%