*01/21 - The Role of Antibiotics in Periodontal Therapy Flashcards
True or false:
- In use of systemic antibiotics, the drug MUST reach the site of action.
- The drug’s concentration at the site of action doesn’t have to be larger than the MIC because it is distributed throughout the whole body.
- The duration of chemotherapy must be sufficient to allow the drug to act.
- true
- FALSE: The drug’s concentration at the site of action must be sufficient to inhibit microflora.
- true
What are the objectives of mouth rinses, local antibiotics, and systemic antibiotics?
- reach the site of action
- attain adequate concentration
- retained for adequate duration
When do we prescribe systemic antibiotics for periodontal problems?
- aggressive periodontitis! (after last SRP)
- failing implant
- periodontal abscess (sometimes)
- NUG (sometimes)
- recurrent (refractory) periodontitis
- poor general response to initial therapy
What type of antibiotics would work for periodontal problems? Why?
generally use metronidazole and amoxicillin
- amoxicillin has enhanced tissue penetration and good activity against gram negatives
- metronidazole has bactericidal activity against strict anaerobes (broad spectrum?)
When do we prefer local delivery of antibiotics instead of systemic antibiotic prescription?
treatment of localized recurrent periodontitis in cases that are otherwise stable
What are the advantages and disadvantages of local delivery?
ADVANTAGES:
- higher local drug concentrations
- sustained therapeutic drug levels (independent of patient compliance)
- effective drug levels can be attained at sites that are difficult to reach
- adverse side effects are minimized
DISADVANTAGES:
- less effective than systemic antibiotics at eradicating invasive bacteria
- can’t eliminate pathogens from the entire oral cavity (recurrent infection possible)
- local delivery technique can be time consuming and may not be cost-effective
What are the advantages and disadvantages of systemic antibiotic use?
ADVANTAGES:
- some periodontal pathogens are invasive which makes them difficult to eliminate by SRP
- some sites are difficult to access with SRP
DISADVANTAGES:
- antibiotics enhance treatment of aggressive periodontitis more than chronic periodontitis
- antibiotic should be administered after SRP to eliminate bacteria in biofilm
- undesirable side effects (antibiotic resistance, microbial overgrowth, hypersensitivity or toxicity)
What are the frequent side effects of the antibiotics: penicillin, tetracycline, metronidazole, and clindamycin?
- PENICILLIN: rashes, allergy, diarrhea
- TETRACYCLINE: nausea, diarrhea, candidiasis, dental staining
- METRONIDAZOLE: nausea, diarrhea, altered taste, antabuse effect
- CLINDAMYCIN: rashes, nausea, diarrhea
Why is chronic periodontitis not routinely treated with antibiotics?
- root planing eliminates most subgingival bacteria associated with chronic periodontitis
- host defense mechanisms are usually effective
- clinical trials show antibiotics are better for treating aggressive periodontitis
What antibiotics are used in periodontal therapy?
- penicillins
- metronidazole
- tetracyclines
- fluoroquinolones
- clindamycin
- macrolides
What are the mechanisms of antibiotic actions?
- undermine the ability of the bacteria to maintain their cell wall
- keep bacteria from making DNA
- poison the 50S and 30S subunits
What are the 3 approaches to deciding which antibiotic to use?
- use empirical approach (based on RCT data); this is the usual approach
- identify pathogens at the site with a molecular technique, then prescribe an antibiotic that will presumably inhibit them
- culture isolated bacteria to identify them and determine their susceptibility to antibiotics
What do the following antibiotics affect?
- penicillins
- metronidazole
- tetracyclines
- fluoroquinolones
- clindamycin
- macrolides
- PENICILLINS: bacterial cell wall
- METRONIDAZOLE: inhibits nucleic acid synthesis
- TETRACYCLINE: protein synthesis (30S) inhibitor
- FLUOROQUINOLONES: DNA gyrase inhibitor
- CLINDAMYCIN: protein synthesis (50S) inhibitor
- MACROLIDES: protein synthesis (50S) inhibitor
What antibiotic is the first prescribed for systemic disease?
penicillins
