13. Pulp Inflammation & Endodontic Microbiology

Question 1

104. Identify the five different portals of entry for microorganisms to colonize the pulp.
     - What’s the most common?

Answer 1

1. Infection via carious lesion (most common)
2. Infection via trauma
3. Infection via “leaky” restoration
4. Infection via periodontal ligament
5. “Mixed” infections with mostly facultative and anaerobic gm- Rods (e.g. BPB)

Question 2

105. When insult/injury/infection occurs to dental pulp, what vascular changes typical of inflammation occur?

Answer 2

1. Increase in blood flow (smaller than in most tissues)
2. Dilation of capillaries
3. Increased permeability of capillaries (edema)

Question 3

105. Just like in most other acute inflammatory processes, what is the first leukocyte to infiltrate the pulp tissue?

Answer 3

Neutrophils (PMN’s)

Question 4

105. If the insult causing inflammation in the pulp is not removed, what processes will develop?

Infiltration by what kind of cells characterizes these processes?

Answer 4

Chronic inflammatory processes result

Characterized by infiltration by mononuclear cells (i.e., macrophages, T cells, and plasma cells)

Question 5

105. PMN’s in acute and macrophages in chronic both try to remove the inflammatory insult. What is one possible drawback to the activity of both of these cells?

Answer 5

Both of the cell types can cause considerable collateral damage to pulp tissues.

Question 6

105. What experimental evidence supports that bacterial infection is an important etiological factor of pulpitis?

Answer 6

There are experiments in which germ-free animals had exposed pulp, but did not develop pulpitis as they always did in conventional animals.

Question 7

106. Describe the prominent bacteria associated with pulpitis

Answer 7

They are normal plaque microflora - mainly subgingival, gram-, facultative, and anaerobic microorganisms.

Question 8

106. What are some gram+ bacteria commonly associated with pulpitis?

Answer 8

Gram+ cocci: Enterococcus (also Strept and Peptostrept)
Gram+ rods: Lactobacillus (also Actinomyces, Eubacterium)

(Remember, it’s mostly subgingival, gram-, facultative, and anaerobic microorganisms)

Question 9

106. What are some gram- bacteria commonly associated with pulpitis?

Answer 9

Gram- cocci: Veillonella
Gram- rods: Fusobacterium, Porphyromonas, Prevotella, Tannerella, Treponema

(also Wolinella, Actinomyces, Campylobacter, dialister, Aggregatibacter, and Campnocytophaga)

(Remember, it’s mostly subgingival, gram-, facultative, and anaerobic microorganisms)

Question 10

107. What role do biofilms play in the success or failure of root canal debridement?

Answer 10

Bacteria within biofilms can be up to 1000x less sensitive to anti-microbial agents

Question 11

107. How might quorum-sensing impact bacterial infection of the pulp?

Answer 11

It may explain how pulp infections can smolder for extended periods of time and then just seem to “blow up”