Antimicrobials

Question 1

What are the advantages and disadvantages of systematic antimicrobials for periodontal treatment?

Answer 1

Advantages:
-	Moderate costs
-	Easy application
Disadvantages:
-	Danger of resistances and superinfections
-	Impacts on whole system

Question 2

What are the advantages and disadvantages of local antimicrobials for periodontal treatment?

Answer 2

Advantages:
- Superior concentrations of active agents is possible
- Less resistance, less superinfections
Disadvantages:
- Costs
- Application can be relatively difficult

Question 3

State some frequent adverse effects of penicillins

Answer 3

Hypersensitivity - mainly rashes, nausea, diarrhoea

Question 4

State some frequent adverse effects of metronidazole

Answer 4

GI intolerance, nausea, diarrhoea, unpleasant metallic taste

Question 5

Describe the 3 different mechanisms that create bacterial resistance

Answer 5

• A = Drugs are pumped back out of bacterial cells through efflux pump proteins to keep intracellular drug concentrations below therapeutic level
• B = Antibiotic is destroyed by chemical modification by an enzyme that is produced by the resistant bacteria
• C = The target structure in the bacterium can be reprogrammed to have a low affinity for antibiotic recognition.

Question 6

What were the findings of the following study: ‘• Rams et al, 2014 - Antibiotic Resistance in Human Chronic Periodontitis Microbiota’

Answer 6

• Patients with periodontitis in the United States frequently yielded subgingival periodontal pathogens resistant in vitro to therapeutic concentrations of antibiotics commonly used in clinical periodontal practice

Question 7

Describe the 3 mechanisms of horizontal gene transfer of bacteria

Answer 7

• Transformation: This occurs when naked DNA is released on lysis of an organism and is taken up by another organism.
• Transduction: antibiotic-resistance genes are transferred from one bacterium to another by means of bacteriophages
• Conjugation: occurs by direct contact between two bacteria: plasmids form a mating bridge across the bacteria and DNA is exchanged

Question 8

What are the findings of studies regarding the use of systemic antibiotics for treatment of chronic periodontitis?

Answer 8

• Systemic antibiotics combined with SRP offer additional clinical improvements compared to SRP alone.

Question 9

What are the findings of studies regarding the use of systemic antibiotics for treatment of aggressive periodontitis?

Answer 9

• These data indicate that a 7‐day adjunctive course of systemic metronidazole and amoxicillin significantly improved the short‐term clinical outcomes of full‐mouth non‐surgical periodontal debridement in subjects with generalised aggressive periodontitis

Question 10

What is the recommended treatment for systemic antibiotics +aggressive periodontitis?

Answer 10

• NSM + antibiotics
• Whole mouth done in a day
• Do the NSM at day 1 of antibiotics
• 400 metronidazole + 500 amoxicillin 7 day course

Question 11

What were the findings of studies regarding the use of systemic antibiotics for treatment of recurrent periodontitis

Answer 11

• There was an overall beneficial effect of the re-treatment, however, was not sustained after the 3 year interval.
• It is suggested that the removal of ‘difficult to reach’ subgingival deposits may require surgical intervention

Question 12

What was the consensus of the paper ‘Herrera et al, 2008 – Antimicrobial therapy in periodontitis: the use of systemic antimicrobials against the subgingival biofilm’?

Answer 12

• If systemic antimicrobials are indicated as part of periodontal therapy they should be adjunctive to mechanical debridement
• There is not enough evidence to support the use of adjunctive antimicrobials with periodontal surgery
• Systemic antimicrobials should not be used in most patients with periodontitis. They should be considered in specific patient groups (aggressive) and defined conditions. Their prescription however should be considered on a case-by-case basis.
• Due to antibiotic resistance the use of systemic antimicrobials should be restricted and they should be used under the most optimal conditions

Question 13

Name 5 types of local adjuncts

Answer 13

• Arestin
• Dentomycin
• Actisite
• Elyzol
• Periochip

Question 14

What were the findings of the following systematic review: ‘Hanes and Purvis, 2003 – Local anti-infective therapy: pharmacological agents. A systematic review’

Answer 14

• Several local anti-infective agents combined with SRP appear to provide additional benefits in PD reduction and CAL gain compared to SRP alone
• The decision to use local anti-infective adjunctive therapy remains a matter of individual clinical judgement, the phase of treatment and the patient’s status and preferences

Question 15

What situations may you use local antimicrobials?

Answer 15

• On maintenance patients with persistent sites with periodontal lesions
• Patients that refuse surgery
• Surgery is contraindicated

Question 16

What is the theory of host modulatory therapy?

Answer 16

Down regulation of MMPs by sub-antimicrobial dose doxycycline confers benefit to patients with periodotntitis