Role of Antibiotics Flashcards
What are some potential indications for systemic antibiotics in perio disease?
- Aggressive periodontitis
- Severe perio abscess
- Severe NUG
Which bacteria in the subgingival biofilm indicate the use of antibiotics?
P. gingivalis and A.a.
T/F: Antibiotics can be useful because deep pockets can be hard to reach, and some bacteria enter the soft tissue.
True
T/F: Antibiotics can be effective without SRP.
False
Biofilm is resistant to antibiotics if not disrupted by SRP
T/F: Bacteria that invade into host tissue are removed with SRP.
False
This is where antibiotics can help
What is the difference between a bactericidal agent and a bacteriostatic agent?
Bactericidal: kills bacteria (homiCIDE, suiCIDE)
Bacteriostatic: slows bacterial growth
T/F: Broad spectrum antibiotics are preferred for treating periodontitis.
False
Narrow-spectrum are preferred because they spare gut bacteria
T/F: Penicillins kill bacteria.
True
But not effective against all A. a. strains
Penicillins are inactivated by _________.
Beta-lactamases
T/F: Penicillins are very good at penetrating epithelium.
False
Effective in gingival fluid
__________ is a penicillin with broad spectrum, enhanced tissue penetration, and is effective against gram negative bacteria.
Amoxicillin
_________ is amoxicillin with a beta-lactamase inhibitor.
Augmentin
Which part of the bacteria do penicillins act on?
Cell wall
_________ is a narrow-spectrum bactericidal agent that is active against strict anaerobes.
Metronidazole
Not as active against A. a.
T/F: Tetracyclines are bacteriostatic, broad-spectrum antibiotics.
True
Tetracyclines inhibit ________ which mediates collagen breakdown in periodontitis.
collagenase
What makes tetracyclines a strong candidate for periodontal antibiotic therapy?
- Inhibits collagenase
2. Occumulated by epithelial cells, gingival fibroblasts, and PMNs
How does tetracycline act on a bacterial cell?
Inhibits protein synthesis (30S inhibitor)
Minocycline and doxycycline are both examples of _________.
tetracyclines
T/F: Fluorquinolones are bacteriostatic.
False
Bacteridical
When would you prescribe a patient with ciprofloxacin?
It is a fluoroquinolone so it is very active against A. a.
So in a patient with aggressive periodontitis it would be very effective
T/F: Ciprofloxacin (fluoroquinolone) can penetrate epithelial cells and phagocytes and can kill invasive bacteria.
True
How does clindamycin act on a bacterial cell?
Inhibits protein synthesis (50S inhibitor)
T/F: Clindamycin would be a good antibiotic for a patient with aggressive periodontitis.
False
Not effective against A. a.
What is a negative side effect specific to clindamycin?
Can induce ulcerative colitis
T/F: Clindamycin is often used in patients who are allergic to penicillin.
True
Azithromycin and clarithromycin are both ________.
Macrolides
Macrolides are ____ inhibitors.
50S
What are the advantages of macrolides?
- Good activity against A. a., P. g., and other gram-negative anaerobes
- Penetrates epithelial tissues
- Bactericidal
- Anti-inflammatory
- Simple regimen
What is the major downside of prescribing macrolides?
Expensive
T/F: Macrolides like clarithromycin reach higher levels in inflamed gingiva than in healthy gingiva.
True
What are some common features of tetracyclines, ciprofloxacin, azithromycin, and clarithromycin?
- Levels in gingival crevicular fluid are often higher than levels in blood
- Actively accumulated by PMNs, fibroblasts, and oral epithelium
- Can kill invasive bacteria
Amoxicillin and metronidazole are both ________ agents. But doxycycline and azithromycin are both ________ agents.
bactericidal; bacteriostatic
T/F: Molecular tests for specific bacteria are more sensitive than culture methods.
True
T/F: Molecular tests for specific bacteria require live bacterial cells.
False
Just DNA
What are the major downsides of bacterial culturing?
- Logistics (cost, transport, availability)
- Not very sensitive
- Difficult to grow spirochetes
When would you want to utilize a microbiological test?
After a poor response to initial therapy
What is the preferred regimen for aggressive periodontitis or severe chronic periodontitis?
Amoxicillin (500mg TID) combined with metronidazole (250mg TID) for 8 days
What are two alternative regimens for patients with penicllin allergies?
- Azithromycin (500mg starting dose, then 250mg/day for 4 days)
- Metronidazole (500mg TID for 7 days)
Antibiotic therapy is most beneficial for patients …..
with deep pockets who are unresponsive to initial treatment, or who have aggressive periodontitis
T/F: Antibiotics are just as effective on patients who undergo surgical therapy as those who undergo non-surgical therapy.
False
Benefits are greater in patients with non-surgical therapy
What are the major limitations of antibiotics in periodontics?
- Not effective without SRP
2. Undesirable side effects
What are some general side effects that can be associated with systemic antibiotics?
- Induce resistance
- Microbial overgrowth
- Hypersesisitivity/toxicity
Dental staining is a side effect often seen with _______.
tetracyclines
Altered taste is a common side effect seen with ______.
metronidazole
Cholestatic jaundice and cardiac arrhythmia are rare side effects associated with _________.
azithromycin
T/F: Dentists can help prevent inducing antibiotic resistance by prescribing broad-spectrum antibiotics and telling patients to only use them until their symptoms are gone.
False
Use narrow-spectrum and have patient take the full dosage
What are the shortcomings of local delivery of antibiotics?
- Less effective at eradicating invasive bacteria
- Recurrent infection from other parts of the mouth
- Time consuming and not cost-effective
What is the current application for local antibiotic delivery?
Treatment of localized recurrent periodontitis in cases that are otherwise stable
