13. Relevance Of Microbiology In Managing Periodontal Diseases

Question 1

LOs

Answer 1

Question 2

What is periodontal disease?

Answer 2

Inflammatory diseases of the tissues supporting the teeth

Question 3

Primary aetiological factors of periodontal disease?

Examples of secondary factors

Answer 3

Question 4

What causes tissue destruction?

Answer 4

Question 5

Why is it important to understand microbial aetiology of periodontal conditions?

Answer 5

1.Prevention
2.Risk assessment
3.Diagnosis
4.Communication
5.Treatment planning
6.Monitoring treatment outcomes

Question 6

Ecology of gingival / periodontal pocket VS healthy?

Answer 6

Question 7

Type of bacteria in healthy gingival

Answer 7

• most predominant = gram pos ~ approx 85-90%
• gram neg ~ approx 10%

Question 8

What happens during gingivitis? ( what bacteria present) ( what can exaggerate/ aggravate gingivitis)

Answer 8

Question 9

Species involved in development of periodontitis

Answer 9

Answer 10

Question 11

Porphyromonas gingivalis virulence factors?

Answer 11

Virulence factors:
- LPS (lipopolysaccharide)
- Fimbriae,
- Proteases (gingipain = most important one that is produced)
- Capsule (can protect these bacterium from host)
- is an obligate anaerobic bacterium

Question 12

Aggregatibacter actinomycetemcomitans
Virulence factors?

Answer 12

Virulence factors:
- Leukotoxin (a protein toxic to polymorphs, monocytes)
- LPS ( endotoxin, triggers immune response, bone resorption)
- Collagenases (responsible for destruction of connective tissues and periodontal ligament fibres and gingival collagen fibres)
- capnofillic bacterium - can survive in low oxygen tensions BUT prefers areas with increased CO2 conc

(CO2 = important growth factor)

Question 13

Necrotising periodontal disease symptoms

Answer 13

(acute necrotizing, Vincent’s disease, trench mouth)

• pain
• bleeding
• halitosis
• necrotizing inflammation of dental papilae
• grey pseudomembranes
• lymph nodes, t0

Question 14

Necrotizing periodontal diseases risk factors?

Answer 14

• dental plaque (most important risk factor)

But greatly influenced by some systemic factors:
- smoking
- poor oral hygiene
- immunosupression
- emotional stress
- poor diet

Question 15

Microbiology of Necrotizing periodontal diseases

Answer 15

This disease is characterised by specific complexes called Fuso-spirochaetal complex

Fuso-spirochaetal complex invades host gingival tissues

Eg of Fuso-spirochaetal complexes
- Treponema spp.
- Fusobacterium spp.
- Prevotella intermedia
- Borrelia vincentii

Question 16

Antibiotics in periodontal therapy

Answer 16

For some patients we can use antibiotics
- Local
- Systemic
In order to improve periodontal conditions and decrease the amount of particular bacteria in dental plaque

• Penicillins- inhibition of cell wall synthesis
• Tetracyclins- inhibition of protein synthesis
• Metronidazole- inhibition of nucleic acid synthesis