Systemic Adjuncts To Perio Treatment - Systemic Antimicrobials

Question 1

What is the aetiological factor of periodontal disease?

Answer 1

Plaque / dental biofilm

Question 2

In dental biofilm which type of bacteria are pathogenic periodontal bacteria

Answer 2

Late colonisers in dental biofilm - form 3-4 days after beginning of dental biofilm formation

Question 3

What are the 2 main pathogens commonly targeted by systemic antimicrobials

Answer 3

P gingivalis
AA

They both invade periodontal tissues
- 2 bacterias that have been shown to invade periodontal tissues + sometimes cannot be eradicated from the subgingival areas

Question 4

Specific plaque theory + keystone periodontal pathogens

Answer 4

Systemic antimicrobials - we are trying to address those keystone pathogens that drive constant inflammation in the periodontal tissues

Question 5

For acute periodontal conditions eg abscesses and necrotising periodontal diseases, what systemic antimicrobial is used

Answer 5

Metronidazole

Question 6

Question 7

Why is dental biofilm important in the use of antibiotics

Answer 7

Dental biofilm is composed of bacteria protected by EPS - extracellular polysaccharides and they communicate between each other and change genes

So Antibiotics are not effective in bacteria that grow in dental biofilm - this is why CONVENTIONAL PERIO TREATMENT IS IMPORTANT IN COMBINATION WITH SYSTEMIC ANTIBIOTICS

Only when we disrupt mature dental biofilm we can achieve environmental factors for antibiotics to have an effect
If we dont disrupt the biofilm - the antibiotics will not have an effect on bacteria as they are protected in the biofilm

Question 8

Why are periodontal diseases treated differently to conventional infections?
MEANING (why do we always have to perform conventional treatment in addition to systemic antimicrobials?

Answer 8

Periodontal diseases are infections BUT they are

• Chronic in nature
• Caused by bacteria normally present in the mouth
• Caused by dysbiotic biofilm
• RSD, the standard periodontal treatment, is very effective

For understanding -

Question 9

Give four examples of adjunctive therapies used after RSD and why they might be used

Answer 9

Question 10

Give four characteristics of antibiotics that must be looked at before prescribing

Answer 10

• Pharmacodynamics
• Pharmacokynetics
• Interactions
• Side effects

Question 11

Give the 3 recommended regimes of systemic antimicrobials in periodontitis

Which antibiotics do you give - in order of preference? 1 is the best to prescribe etc

Answer 11

1. Amoxicillin + Metronidazole
2. Metronidazole
3. Azithromycin

First choice antibiotic is amoxicillin + metronidazole

Question 12

Amount of amoxicillin + metronidazole , how many days ?

Mechanism of action for both?

Answer 12

Amoxicillin 500mg/ 3x a day for 7 days
Metronidazole 400mg/3x a day for 7 days

Amoxicillin - inhibits the bacterial glycans in gram positive bacteria.
Metronidazole - affects DNA synthesis and replication in anaerobic gram negative bacteria.
By using both - target gram positive and gram negative bacteria

Question 13

Amount of metronidazole , how many days ?

Answer 13

400mg 3x a day 7 days

Question 14

Amount of azithromycin , how many days ?

Mechanism of action ?

Answer 14

500mg/1x3d

Macrolide antibiotics

Mechanism of action - inhibits ribosomes, which stops the synthesis of proteins of bacterial cells.
Convenient for patient as dose is only for 3 days + can accumulate in immune cells after the 3 days, boosting protection, also has anti-inflamm characteristics