L2 Antimicrobials in periodontology Flashcards
Which microorganisms are associated with periodontal disease?
All gram negative bacteria, mostly anaerobic
- P. gingivalis
- Aggregatibacter actinomycetemcomitans (Facultative)
- Tannerella forsythensis
- Spirochetes of acute NUG
- Prevotella intermedia
- F nucleatum
- T denticola
What would antibiotics in periodontology need to target?
Would need abx effective against gram negative, anaerobic microorganisms and spirochetes.
Name the 4 types of antibiotic used in perio.
- Penicillin
- Nitroimidazoles
- Macrolides
- Tetracyclines
Describe the action of penicillins.
- Used for acute infections from gram +ve and -ve bacteria
- Not effective against aggregatibacter actinomyces
- Inhibit bacterial cell wall synthesis
- Most popular choice is amoxicillin
Describe the action of nitroimidazoles.
- E.g. Metronidazole
- Act by inhibiting DNA synthesis
- Broad spectrum, act against anaerobic cocci, gram +ve and -ve bacilli
- Very effective against anaerobes
- High concentration in GCF (up to twice of serum)
Metronidazole interacts with what drugs?
- Strong interaction with alcohol (pt needs to wait 48 hours after finishing abx to drink)
- Strong interaction with Warfarin, potentiates effects of Warfarin making pt at high risk of severe bleed
Describe the action of macrolides.
- E.g. Azithromycin
- Acts by disrupting protein synthesis
- Conventionally used to treat respiratory tract infections
- Alternative for pts allergic to penicillin
- Some benefits in grade C periodontitis and deeper sites
Name 3 tetracyclines.
- Tetracycline
- Minocycline
- Doxycycline
Describe the action of tetracyclines.
- Inhibit protein synthesis
- Effective against gram positive, spirochetes, anaerobic and falcutative bacteria
- High concentration in GCF
- Most commonly prescribed antibiotic in perio
When should tetracyclines be avoided?
- Children under 12, pregnant women, breastfeeding women (significant tooth staining)
- Patients with kidney disease (can exacerbate renal failure)
What substances decrease the absorption of tetracycline?
- Milk
- Antacids
- Calcium
Compare doxycycline vs tetracycline.
- Similair efficacy and spectrum
- Doxycycline concentration in GCF is higher than tetracycline
- Absorption is less sensitive to presence of food
At what stage of treatment are antimicrobials considered?
- Step 2 therapy
- For a compliant and engaged patient, good OH, low bleeding
Name some local delivery methods for antimicrobials.
- Mouth rinses and toothpastes (hypothetical)
- Subgingival irrigation
- Local delivery of abx
How many times does GCF turn around per hour?
GCF turns around 40 times per hour.
What are the 3 principles Goodson suggested for local delivery of antimicrobials in periodontal treatment?
Goodson principles 1996:
- The drug needs to be efficient in the periodontal pocket
- The drug concentration needed to be high enough
- Duration of the drug needed to be sufficient
What are the advantages of local delivery of antimicrobials?
- Applied directly to target area
- Higher concentrations achieved directly in the perio pocket
- Not reliant on pt compliance
- Reduced systemic side effects
- Reduced risk of resistance
What are the disadvantages of local delivery of antimicrobials?
- Expensive
- Delivery to the base of the pocket is questionable
- May result in failure of pocket closure
- Not active on the mature biofilm (antimicrobials require a clean surface to be effective)
Which 2 antimicrobials are used locally and how?
- Minocycline HCl 1mg (preloaded syringes: Dentomycin or Arestin)
- Chlorhexidine (gelatine discs, PerioChip)
Explain how Minocycline HCl 1mg is used and the treatment outcomes.
- Preloaded syringes (Dentomycin or Arestin)
- Applied every 2 weeks (3 times in total)
- Broad spectrum antibiotic which suppresses rods and spirochetes
- Reduces P.gingivalis and Aa
- 0.4mm clinical gains have been reported
Explain how chlorhexidine is used and the treatment outcomes.
- Hydrolysable gelatine disc placed into perio pocket of 5mm or more
- PerioChip contains 2.5mg chlorhexidine
- Requires 3 applications over 6 months
- Pt must avoid ID cleaning for 10 days after placement
- Maintains GCF concentrations for 7 days
- £20 per chip
What does current evidence suggest regarding the efficacy of local antimicrobials?
- EFP S3 guidance states that locally delivered antibiotics or Chx as an adjunct to subgingival instrumentation in periodontitis pts may be considered
- Grade 0 recommendation
- FGDP does not recommend locally delivered antimicrobials due to low quality evidence
When are local antimicrobials indicated?
- In isolated pockets which have not responded to conventional non-surgical treatment on several occassions
+ - Where there is no detectable calculus at the site and where the pt is maintaining good levels of plaque control
What are the advantages and disadvantages of systemic antimicrobial delivery?
Advantages:
- Cheaper
- Better evidence
Disadvanatges:
- Systemic side effects
- Increased resistance
- Requires good pt compliance
- Ineffective against mature biofilm
- Concentrations in GCF potentially lower than for local delivery
