Aetiology and Pathogenesis

Question 1

What are local plaque retention factors? (4 points)

Answer 1

• Calculus
• Restoration margins
• Crowding
• Mouth breathing

Question 2

What are systemic modifying factors for plaque/gingivitis? (2 points)

Answer 2

• Sex hormones

- Medication

Question 3

What characteristics define gingival health? (3 points)

Answer 3

• Knife edge, scalloped gingival margin
• Stippling (in about 30%)
• Pink

Question 4

What are defining features of periodontitis? (2 points)

Answer 4

• Irreversible loss of attachment of the epithelium

- Bone low

Question 5

Does gingivitis always progress to periodontitis?

Answer 5

• No

- But it can and in many cases will

Question 6

Once periodontitis is initiated, is progression of the attachment loss episodic or continuous?

Answer 6

• Can be either
• Hard to judge how fast it goes once initiated
• Different sites within the same mouth may be affected to markedly varying degrees

Question 7

What is the rate of progression loss of attachment in periodontitis like?

Answer 7

• Generally very slow (0.05-0.1mm per year) but this is highly variable

Question 8

What is biofilm?

Answer 8

• One or more communities of microorganisms, embedded in a glycocalyx, attached to a solid surface

Question 9

What are 4 properties of biofilm?

Answer 9

• Provide protection for colonising species from competing organisms and environment (host defences, antibiotics)
• Facilitate uptake of nutrients and removal of metabolic products
• Development of appropriate physiochemical environment e.g. pH, O2 concentration
• Communication between bacteria

Question 10

What 2 features can increase the bacteria’s virulence?

Answer 10

• Ability to colonise and compete in an ecological niche

- Ability to evade host defences

Question 11

How can bacteria evade host defences? (4 points)

Answer 11

• Degrade host immunoglobin and complement
• Leukotoxin production
• Tissue invasion
• Inhibition of antibody synthesis

Question 12

Does a specific bacteria cause periodontal disease?

Answer 12

• Not one single bacteria has been proven causative

Question 13

What is possible evidence needed to prove that a specific bacteria is the cause of something? (5 points)

Answer 13

• Presence in elevated numbers at diseased sites
• Reduced numbers following periodontal therapy
• Presence of an elevated specific immune response
• Production of virulence factors
• Evidence from animal models

Question 14

Which complex of bacteria makes you likely to have perio problems? (3 points)

Answer 14

• P. gingivalis
• B. forsythus
• T. denticola

Question 15

Can periodontitis occur without the presence of bacteria ?

Answer 15

• No

Question 16

Periodontitis is a synergistic infection. What does this mean?

Answer 16

• Not just one bacteria that causes it (plaque ecology is important)

Question 17

What are examples of mechanisms that contribute to the host response against perio problems? (4 points)

Answer 17

• Saliva
• Epithelium (physical barrier, shedding of cells, production of inflammatory mediators)
• GCF
• Inflammatory and immune responses

Question 18

Which type of cell is the initial periodontal lesion composed of?

Answer 18

• T lymphocytes

Question 19

The initial periodontal lesion is compromised mainly of T lymphocytes. Which cells predominate in a later stage? (2 points)

Answer 19

• B cells

- Plasma cells

Question 20

Antibody is produced locally at the initial periodontal lesion. What is its likely role?

Answer 20

• Likely protective role

Question 21

What are the protective functions of an antibody? (4 points)

Answer 21

• Inhibition of adhesion/invasion
• Complement activation
• Neutralisation of toxins
• Opsonisation and phagocytosis

Question 22

What are MMP’s? (2 points)

Answer 22

• Matrix metalloproteinases are a family of zinc and calcium dependent proteolytic enzymes, which include collagenases
• In periodontitis, Matrix degradation is largely a result of MMP’s secreted by host inflammatory cells

Question 23

What are general risk factors of periodontitis? (6 points)

Answer 23

• Smoking
• diabetes
• stress
• Drugs
• Systemic disease
• Nutrition

Question 24

What are risk determinants of periodontal disease? (3 points)

Answer 24

• Genetics
• Socioeconomic status
• Gender

Question 25

What are anatomical risk factors that can cause periodontitis? (4 points)

Answer 25

• Enamel pearls/projections
• Grooves
• Furcations
• Gingival recession

Question 26

What tooth positions are predisposed to perio problems? (5 points)

Answer 26

• Malalignment
• Crowding
• Tipping
• Migration
• Occlusal forces

Question 27

What are iatrogenic risk factors for periodontitis? (4 points)

Answer 27

• Restoration overhangs
• Defective crown margins
• Poorly designed partial dentures
• Orthodontic appliances

Question 28

Why can smoking contribute to periodontitis? (5 points)

Answer 28

• Vasoconstriction of gingival vessels and increased gingival ke ratinisation
• Impaired antibody production
• Depressed numbers of Th lymphocytes
• Impaired PMN function
• Increased production of pro-inflammatory cytokines

Question 29

What is the primary aetiological agent in inflammatory periodontal disease?

Answer 29

• Microbial plaque

Question 30

Look at actual lecture for more info

Answer 30

:)