Role of Antibiotics in Periodontal Therapy

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Role of Antibiotics in Periodontal Therapy

• Dentistry 664

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Aggressive Periodontitis Antibiotics Indicated
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Recurrent (refractory) Periodontitis
Antibiotics often indicated
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Acute Necrotizing Ulcerative Gingivitis
Antibiotics may be indicated
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Periodontal Abscess Antibiotics may be indicated
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Chronic periodontitis is rarely treated with
antibiotics

• Scaling and root planing eliminates most species
  of subgingival bacteria associated with chronic
  periodontitis
• Host defense mechanisms are usually effective at
  controlling infections

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Indications for Antibiotic Therapy

• Acute infections
• Aggressive (early onset) forms of periodontitis
• Recurrent (refractory) periodontitis
• Certain systemic disorders

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Requirements for Effective Antimicrobial
Chemotherapy

• The drug must reach the site of action
• The drugs concentration at the site of action
  must be sufficient to inhibit bacteria
• The duration of chemotherapy must be sufficient
  to allow the drug to act

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To inhibit subgingival bacteria, an antimicrobial
agent must be able to reach the base of the
periodontal pocket
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Stratification of Subgingival Plaque
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Mechanisms of Antibiotic Action
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Antimicrobial mouthrinses

• Possess broad spectrum antimicrobial activity
• Do not attain adequate concentrations at the base
  of the periodontal pocket
• Are not retained for an adequate duration

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Systemic Antibiotics

• May have narrow or broad spectrum antimicrobial
  activity
• Can potentially reach the pocket and its soft
  tissue wall
• Can potentially attain inhibitory levels in the
  pocket
• Can potentially be retained for an adequate
  duration

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Microorganisms Associated With Localized
Aggressive Periodontitis

• Actinobacillus actinomycetemcomitans
• Eikenella corrodens
• Fusobacterium nucleatum

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Microorganisms Associated With Recurrent
(Refractory) Periodontitis

• Porphyromonas gingivalis
• Prevotella intermedia
• Eikenella corrodens
• Fusobacterium nucleatum
• Campylobacter rectus

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Key Pathogens

• Actinobacillus actinomycetemcomitans
• Porphyromonas gingivalis
• Prevotella intermedia

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Antibiotics Used in Periodontal Therapy

• Penicillins (e.g., amoxicillin)
• Metronidazole
• Tetracyclines (e.g., doxycycline)
• Fluoroquinolones (e.g., ciprofloxacin)
• Clindamycin
• Erythromycin

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Penicillins

• Bactericidal
• Reach effective levels in gingival fluid
• Dont inhibit all A.a. Strains
• Inactivated by ß-lactamases
• Amoxicillin has enhanced tissue penetration and
  good activity against gram negatives
• Augmentin is as effective as amoxicillin, but
  resists inactivation by ß-lactamases

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Metronidazole

• Bacteriocidal activity against strict anaerobes
• Less active against facultative pathogens (A.a.
  and Eikenella corrodens)

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Tetracyclines

• Have bacteriostatic activity against most
  periodontal pathogens.
• Can reach higher levels in gingival fluid than in
  blood serum.
• Inhibit collagenase, which mediates collagen
  breakdown in inflammatory disease.

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Doxycycline levels are less variable in gingival
crevicular fluid than in blood serum
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Fluoroquinolones (Ciprofloxacin)

• Bactericidal
• Extremely active against A.a., but less active
  against anaerobic bacteria
• Reach higher levels in gingival fluid than in
  blood serum
• Penetrate epithelial cells-can kill invasive
  bacteria

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Distribution of systemic doxycycline and
ciprofloxacin in serum, gingival connective
tissue (GCT) and gingival fluid (GCF)
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Clindamycin

• Potent bacteriostatic activity against strict
  anaerobes
• Less effective against facultative pathogens
  (A.a. and Eikenella)
• Can induce ulcerative colitis
• Often used as an alternative antimicrobial agent
  in penicillin-allergic patients

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Erythromycin

• Doesnt reach effective concentrations in
  gingival fluid
• Weak activity against A.a., Eikenella and
  Fusobacterium

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Deciding Which Antibiotic to Use

• Empirical approach
• Identify suspected pathogens at the site with
  culture or DNA probes, then prescribe an
  antibiotic that will presumably inhibit them
• Culture isolated bacteria to identify them and
  determine their susceptibility to antibiotics

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Advantages of Culturing Techniques

• Reflects viable bacteria in the pocket
• Can assess the predominance of a particular
  bacterial pathogen
• Can grow and study unusual bacteria
• Facilitates determination of antibiotic
  susceptibility
• Classical technique

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Disadvantages of Culturing Techniques

• Very costly
• Very time consuming
• Problems with transport to the lab
• Difficult to grow fastidious organisms (e.g.,
  spirochetes)
• Accuracy dependent on good sampling technique
• Not very sensitive

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DNA Probe Tests for Microbial Evaluation

• Permits reliable detection of specific pathogens
  in subgingival plaque specimens
• Available as a reference laboratory service

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Sampling deepest pockets with a paper point
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Laboratory processing of bacterial samples with
DNA probes
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Advantages of DNA Probe Tests

• Plaque specimens are easy to collect.
• Plaque collection is noninvasive.
• Tests are specific for A.a., P.g., P.i., F.n. and
  C.r.
• More sensitive than culture methods.
• Tests quantify bacteria at physiologically
  relevant ranges.
• Tests require DNA, not live cells.

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How to best use microbiological tests?

• Complete initial periodontal therapy before
  testing.
• Assess the response to initial therapy. If not
  ideal, sample deepest pockets and test for
  presence of pathogens with DNA probes.
• Prescribe an antimicrobial regimen that is active
  against pathogens identified by test.

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Antibiotic Regimens for Treating Aggressive and
Recurrent Periodontitis

• Tetracycline HCl (250 mg QID) for 21 days (one of
  the oldest regimens)
• Amoxicillin (500 mg TID) and metronidazole (250
  mg TID) for 8 days (most commonly prescribed-more
  effective than a single agent)
• Metronidazole (500 mg BID) and ciprofloxacin (500
  mg BID) for 8 days (usually very effective for
  mixed infections)

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Limitations of Systemic Antibiotics in
Periodontics

• Antibiotics rarely enhance the treatment of
  chronic periodontitis
• To eliminate bacteria in biofilms effectively,
  antibiotics must be used in conjunction with
  mechanical debridement
• No single antibiotic can inhibit all periodontal
  pathogens
• Antibiotics can have undesirable side effects
  when given systemically

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Adverse Side Effects Associated With Systemic
Antibiotics

• Induction of antibiotic resistance
• Induction of microbial overgrowth
• Inhibition of oral contraceptives (rare)
• Hypersensitivity or toxicity (e.g., allergy,
  nausea, diarrhea, photosensitivity)

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Local Delivery of Antibiotics 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