Systemic antibiotics in periodontics

Question 1

What is chemotherapy in the context of periodontics?

Answer 1

The treatment or control of a disease by chemical agents.

Question 2

What does adjunctive treatment mean in periodontics?

Answer 2

Supplementary and additional therapeutic procedures.

Question 3

What are the objectives of chemotherapy?

Answer 3

Control plaque (anti-plaque agents)

Kill pathogens (antimicrobials)

Inhibit tissue loss (host-modulating agents)

Enhance healing/Promote regeneration

Question 4

What does the ideal chemotherapeutic agent do?

Answer 4

Kill/inhibit target organisms
Reach the site
Adequate concentration
Substantivity
Do not harm/ minimal drug resistance
Cost effective

Question 5

What is important about antibiotic concentration in periodontal therapy?

Answer 5

It must be adequate at the infection site.

Question 6

Where should antibiotics reach in periodontal tissues?

Answer 6

Crevice/pocket area, epithelial cells, and connective tissue cells.

Question 7

Which antibiotics penetrate well into gingival crevicular fluid (GCF)?

Answer 7

Tetracycline and metronidazole.

Question 8

Which antibiotic retains good activity in low pH?

Answer 8

Metronidazole.

Question 9

What must antibiotic tissue concentration meet or exceed?

Answer 9

The minimal inhibitory concentration (MIC).

Question 10

Which type of chemotherapeutic has greater potential to reach the site?

Answer 10

Local.

Question 11

Why might systemic drugs have reduced site concentration?

Answer 11

Due to the first-pass effect.

Question 12

Which type of chemotherapy more easily achieves subgingival concentration?

Answer 12

Local.

Question 13

How is the duration of effect for local chemotherapeutics?

Answer 13

Good.

Question 14

What are common side effects of systemic chemotherapeutics?

Answer 14

Microbial resistance, systemic reactions (allergies, nausea, vomiting, diarrhea, drug interactions).

Question 15

Are side effects common with local chemotherapeutics?

Answer 15

Almost not reported; if they occur, they are restricted to the site.

Question 16

What are indications for local chemotherapeutic use?

Answer 16

Localized periodontal disease and recurrent/refractory cases.

Question 17

What are indications for systemic chemotherapeutic use?

Answer 17

As an adjunct to non-surgical therapy, especially when host-response is impaired (e.g., diabetes, smoking).

Question 18

Which chemotherapeutic agents have good ability to reach the disease site?

Answer 18

Subgingival irrigation, systemic antibiotics, and locally delivered antimicrobials.
(✘ Mouth rinse = Poor)

Question 19

Which agents have good duration of effect?

Answer 19

Only locally delivered antimicrobials.
(✘ Mouth rinse & subgingival irrigation = Poor, Systemic antibiotics = Fair)

Question 20

Which agents are most effective at killing or inhibiting target microbes?

Answer 20

Systemic antibiotics and locally delivered antimicrobials.
(✘ Mouth rinse = Poor, Subgingival irrigation = Fair)

Question 20

Which agents achieve good concentration at the site?

Answer 20

Mouth rinse, subgingival irrigation, and locally delivered antimicrobials.
(✘ Systemic antibiotics = Fair)

Question 21

Which chemotherapeutics are safest (do not harm the patient)?

Answer 21

Mouth rinse, subgingival irrigation, and locally delivered antimicrobials.
(✘ Systemic antibiotics = Fair due to potential side effects)

Question 22

When are bacteriostatic agents sufficient for treatment?

Answer 22

When the host immune response is intact.

Question 22

When can bacteriostatic agents become bactericidal?

Answer 22

At higher concentrations.

Question 23

What are factors affecting antimicrobial activity in the periodontal pocket?

Answer 23

The total bacterial mass Bacterial invasion Bacterial population in biofilm Subgingival recolonization of the pocket from supragingival plaque Binding of the drug to other non-target microorganisms and tissues

Question 24

What are examples of systemic antibiotics used in periodontal therapy?

Answer 24

Tetracyclines, metronidazole, penicillins, azithromycin, clindamycin, and combinations.

Question 25

What are examples of a host-modulating agent?

Answer 25

Low-dose systemic doxycycline (e.g. Periostat) NSAIDs (e.g. Flurbiprofen) Bone sparing agents (e.g. Bisphosphonates)

Question 26

What are examples of tetracyclines used in periodontal therapy?

Answer 26

Tetracycline-HCl, minocycline, and doxycycline.

Question 27

Are tetracyclines bacteriostatic or bactericidal?

Answer 27

Bacteriostatic.

Question 28

What type of bacteria are tetracyclines generally more effective against?

Answer 28

Gram-positive bacteria.

Question 29

What is the mechanism of action of tetracyclines?

Answer 29

Inhibit protein synthesis and collagenase.

Question 30

How does the concentration of tetracyclines in the gingival crevice compare to serum?

Answer 30

It is 2–10 times higher in the gingival crevice (4–8 μg/ml).

Question 31

Why is tetracycline effective against periodontal pathogens?

Answer 31

Its crevicular concentration exceeds the minimal inhibitory concentrations (MICs).

Question 32

What is the concentration range of doxycycline in gingival crevicular fluid (GCF)?

Answer 32

1.2 – 8.1 μg/ml.

Question 33

What are some advantages of doxycycline over tetracycline-HCl?

Answer 33

Fewer side effects, safe with renal dysfunction, fewer GI disturbances, and lower risk of resistance.

Question 34

What are contraindications or warnings for doxycycline?

Answer 34

Hypersensitivity to tetracyclines, photosensitivity, and risk of candidiasis.

Question 35

What is the primary mechanism of action of low dose doxycycline (LDD)?

Answer 35

Anti-collagenase activity; inhibits matrix metalloproteinase (MMP) activity.

Question 36

What is the first-choice antibiotic for orodental infections?

Answer 36

Amoxicillin.

Question 37

What is the mechanism of action of amoxicillin?

Answer 37

Inhibits cell wall synthesis; bactericidal.

Question 38

What type of bacteria does amoxicillin target?

Answer 38

Both Gram-positive and Gram-negative bacteria.

Question 39

What effect does amoxicillin with scaling and root planing (SRP) have on bacteria?

Answer 39

Reduces red and orange complex bacteria; 71% reduction of Porphyromonas gingivalis one year after treatment (Feres et al. 2012).

Question 40

When is amoxicillin/clavulanate commonly used?

Answer 40

In refractory periodontitis.

Question 40

What is the benefit of combining amoxicillin with clavulanate (Augmentin®)?

Answer 40

Inhibits β-lactamase, making amoxicillin more effective against many bacteria.

Question 41

What is the mechanism of action of metronidazole?

Answer 41

Bactericidal; inhibits DNA synthesis.

Question 42

How effective is metronidazole in periodontal therapy?

Answer 42

Achieves serum and GCF concentrations above MICs for most periodontal pathogens.

Question 43

Which organisms is metronidazole especially effective against?

Answer 43

Spirochetes (e.g., in ANUG) and Gram-negative anaerobic rods.

Question 44

What are the contraindications for metronidazole use?

Answer 44

Hepatic disease, pregnancy (1st trimester), and concurrent alcohol intake.

Question 45

What class of antibiotic is azithromycin?

Answer 45

Broad-spectrum macrolide.

Question 46

What is notable about azithromycin’s distribution in the body?

Answer 46

It reaches high tissue concentrations.

Question 47

What is the mechanism of action of azithromycin?

Answer 47

Bacteriostatic; inhibits protein synthesis by binding to the 50S ribosomal subunit.

Question 48

What are common side effects of azithromycin?

Answer 48

Nausea, diarrhea, abdominal pain, vomiting, and flatulence.

Question 48

What historical role did clindamycin play in dental prophylaxis?

Answer 48

It was the first antibiotic used for prophylaxis in patients allergic to penicillin.

Question 49

What is clindamycin commonly used to treat in periodontics?

Answer 49

Refractory periodontitis.

Question 50

Is clindamycin bacteriostatic or bactericidal?

Answer 50

Bacteriostatic.

Question 51

What type of bacteria is clindamycin effective against?

Answer 51

Gram-negative anaerobic bacteria.

Question 52

What is a major precaution when using clindamycin?

Answer 52

Risk of pseudomembranous colitis.

Question 53

Which antibiotic combination showed the greatest improvement in clinical attachment level (CAL) in deep pockets?

Answer 53

Metronidazole and amoxicillin (Herrera et al. 2002).

Question 54

What is a downside of using the metronidazole and amoxicillin combination?

Answer 54

Highest frequency of adverse events, such as nausea, vomiting, and allergic reactions.

Question 55

What clinical outcomes showed overall improvement with systemic antibiotics + SRP?

Answer 55

CAL PPD BOP

Question 55

When is the best time to administer antibiotics in periodontal therapy?

Answer 55

Immediately after the last session of scaling and root planing (SRP).

Question 56

What can overuse or misuse of antibiotics lead to?

Answer 56

Development of resistant bacterial strains and antibiotic resistance genes.

Question 57

According to the CDC, how many antibiotic prescriptions are unnecessary?

Answer 57

One-third.

Question 58

What may happen due to selective pressure from antibiotics?

Answer 58

Increased growth of opportunistic organisms.

Question 59

When should adjunctive systemic antibiotics be used in periodontal therapy?

Answer 59

Only when cases cannot be managed with mechanical and surgical therapy alone.

Question 60

What are clinical indications for adjunctive antibiotic use?

Answer 60

Continuing periodontal breakdown despite hygienic phase therapy high risk for breakdown, rapid progression (Grade C) severe acute infections