Role of Antibiotics in Periodontal Therapy Flashcards
What are indications for Systemic Antibiotic Therapy
Aggressive Periodontitis Failing Implants Periodontal abscess (sometimes) NUG (sometimes) Recurrent periodontitis Chronic periodontitis Poor general response to initial therapy
When do you use systemic antibiotics to treat aggressive periodontitis?
Always
Why do we use systemic antibiotics to treat failing implants?
We can’t do an SRP on them, and they’re hard to disinfect, so antibiotics can help eliminate an infection
When do we use systemic antibiotics when treating Periodontal Abscesses and/or NUG?
If the infection is growing, and patient has fever, malaise, swollen lymph nodes, etc
About 50% of the time
We use them in conjunction with typical periodontal treatments
When do we use systemic antibiotics with chronic periodontitis?
It is limited to cases with multiple deep pockets
What is the rationale for using systemic antibiotics?
Some periodontal pathogens are invasive, making them difficult to eliminate via SRP (A. actinomycetemcomitans; P. gingivalis; P. intermedia)
These species will recolonize fairly easily, because after SRP, the pockets have been cleaned and there is a lot less for them to compete with
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 suggest that antibiotics are of greater benefit treating aggressive periodontitis than chronic
Systemic antibiotics are helpful in periodontal therapy if…
They distribute to the pockets and its soft tissue wall
They reach inhibitory levels in the pocket
Their levels are maintained for an adequate duration
They penetrate host cells and kill invasive bacteria
What is the pathway for antibiotics to distribute to the periodontal pocket?
Release from the capillaries and CT, percolates through the JE and into the gingival crevice
What section of the biofilm do we want antibiotics to target? Why?
We want to target bacteria in the middle section of the biofilm
Bacteria in the middle struggle to gain nutrients, so they have lower metabolic rate and proliferation rate
What types of antibiotics are used in periodontal therapy?
Penicillins Metronidazole Tetracyclines Fluroquinolones Clindamycin Macrolides
What is the mechanism of Fluoroquinolones
Mess up the unwinding of DNA
What is the mechanism of Cindamycin
Mess up protein synthesis (50S ribosome)
What is the mechanism of Tetracyclines
Mess up protein synthesis (30S ribosome)
What is the mechanism of Penicillins
Mess up the cell wall
Penicillin
Bactericidal
Inactivated by B-lactamases
Reach effective levels in gingival levels
Don’t inhibit A.a strands
Don’t penetrate epithelial cells very well
Amoxicillin has enhanced tissue penetration and good activity agains gram-
Augmentin is as effective as amoxicillin, and it is resistant to inactivation by B-lactamases
Metronidazole
Bactericidal activity against strict anaerobes
Less potent activity against facultative bugs like A.a.
Tetracyclines (minocycline and doxycycline)
Bacteriostatic against most periodontal pathogens
Can reach higher levels in gingival fluid than in blood serum
Inhibit collagenase, which mediates collagen breakdown in periodontitis
Actively accumulated by oral epithelial cells, gingival fibroblasts, and PMNs
How do Tetracylines reach higher levels in gingival fluid than blood serum?
Cells of the gingiva act as a small reservoir and uptake it to capactiy (which is 50-60x higher than ECM)
It is a reversible storage, so when tissue levels of Tetracycline is low, it can get released
Levels can decrease in the blood, but stay fairly constant in GCF because it is stored
Fluoroquinolones
Bactericidal
Extremely active against A.a, but less active against anaerobic bacteria like P.g.
Reach higher levels in gingival fluid than in blood
Penetrate epithelial cells and phagocytes and can kill invasive bacteria
How does Ciprofloxacin work?
Enhances PMNs bactericidal ability againt A.a
The effect is most significant when the Bacteria:PMN ratio is high
Clindamycin
Potent bacteriostatic activity against strict anaerobes
Less effective against facultative pathogens like A.a
Can occasionally induce ulcerative colitis
Often used as an alternative antimicrobial agent in penicillin-allergic patients
Macrolides/Erythromycin
Not especially effective at concentrations seen in gingival fluid
Weak activity against A.a.
Very few clinical trials in treatment of periodontitis
Azithromycin and Clarithromycin
Reach high concentrations in tissues
Have good activity against A.a, P.g, and many other gram- anaerobes
Penetrates epithelial cells and kills invasive bacteria - also taken up by PMNs and fibroblasts
Macrolides produce anti-inflammatory effects
