a antibiotics

Control of Microorganisms by Antibiotics

Weinberg, chapter 11

Properties of an Ideal Antibiotic

1. Bacterial specificity

2. Should not produce resistant strains

3. Does not cause allergy or toxicity

4. Does not cause other side effects

5. Does not eliminate normal oral flora

6. Cost effective

7. Hence the ideal has not been found!

Antibiotic Adjunctive Therapies

• Treatment of aggressive periodontal diseases, chronic periodontitis, refractory periodontitis– Initial identification of pathogens– Appropriate antibiotic selection– Debridement should be carried out first

• Systemic antibiotics commonly prescribed:– tetracyclines, metronidazole– amoxicillin, Augmentin, ampicillin– ciprofloxacin, clindamycin– Periostat (doxycycline)

Systemic Use – Concerns

• Common side effects:– Nausea, GI upset

– Diarrhea

– Rash

• Resistant bacteria• Poor client

compliance

• May be to broad spectrum

• Common oral manifestations:– Black hairy tongue

– Oral candidiasis

Controlled Release Agents

• Work by suppressing destructive enzymes produced during inflammatory process or suppressing microbes

• Considered for localized periodontal sites• Systems available include:

– Actisite (tetracycline fiber)– Atridox (doxycycline gel)– Arestin (minocycline microsphere)

Advantages of Controlled Release Agents

• Client compliance not an issue

• GCF concentration greater than serum levels

• Delivery is localized – reduces systemic effects

• Reduced side effects

Tetracycline

• Clinical Use:– Refractory periodontitis– Localized aggressive periodontitis– Growing trend to use combination therapies –

more effective– Systemic & local delivery systems

Tetracycline

• Mechanism of action:– Bacteriostatic, broad spectrum – More effective against gram-positive bacteria– However, A.a. highly susceptible– Non-antibacterial properties:

• Inhibits production & secretion of collagenase

• Inhibits bone resorption

Tetracycline

• Mechanism of action:– Antibacterial properties:

• Inhibits growth & multiplication of bacteria

• Dosage:– 250 mg for 2 weeks

Tetracycline – Side Effects

• Intrinsic tooth staining

• GI upset, abdominal pain

• Diarrhea, vomiting• Fungal overgrowth• Resistant bacterial

strains

• Interferes with bactericidal activity of penicillin's & cephalosporins

• Reduces effect of BCP

Actisite Periodontal Fiber

• Clinical use:– Pockets measuring 5 mm, bleed on probing

– Localized treatment for sites that have not responded to previous mechanical therapy

• How supplied:– Cartons of 4 or 10 fibers

– 23 cm in length

– 12.7 mg tetracycline hydrochloride

– Stored at room temperature

Actisite

• Application:– Treat one quadrant or one side of mouth at a

time– Client may request anaesthesia– Fiber inserted into pocket (circumferential or

not)• Takes about 10 minutes/tooth

– Some control of saliva– Should contact pocket base

Actisite

• Application:– Sealed in place with adhesive

• Apply in thin even line along gingival margin• Surgical dressing not necessary but has been used

– Removed 7-10 days after placement• Curette and/or cotton pliers• Fiber comes out in mass or pieces• Debride areas as necessary

– Tissue may appear red following removal

Actisite

• Adverse effects:– Discomfort– Local erythema– Little systemic reaction– Used with caution in client with history of

candidiasis– Application around 12+ teeth may result in

oral candidiasis

Actisite

• Client instructions:– Avoid brushing & flossing– Use antimicrobial rinse

• Use of CHX may have syngerstic effect

– Avoid hard or crunch foods, stick foods, chewing gum

Actisite

• Clinical Efficacy:– Reduction in bleeding on probing and pocket

depth• More significant reductions in deeper pockets

– Reduction in periodontal pathogens– Effects of fiber on bone loss, tooth mobility or

tooth loss not established

Metronidazole

• Clinical use:– Refractory periodontitis (when combined with

amoxicillin or Augmentin)– Necrotizing ulcerative gingivitis– Moderate – severe periodontitis– Aggressive periodontitis (LAP) when

combined with amoxicillin or Augmentin– Following perio surgery if barrier membranes

in place – suppresses P.g.

Metronidazole

• Mechanism of action:– Bactericidal antimicrobial

– Disrupts DNA synthesis leading to cell death

– Selectively kills bacterial associated with periodontal disease

– Susceptible bacteria include:• Fusobacterium, Bacteroides

• Peptostreptococcus

• Treponema, Campylobacter

• Veillonella

Metronidazole – Side Effects

• GI disturbances• Headache• Dry mouth• Candida infections• Metallic taste

• Nausea, diarrhea• Stomatitis• Avoid alcohol when

taking: acute nausea, headache, vomiting

• May decrease effects of BCP

Metronidazole

• Clinical Considerations:– GCF concentrations > blood serum levels– When combined with oral hygiene &

debridement = beneficial effect on periodontitis

• Periodontal surgery may not be necessary

– Doxycycline may be substituted for metronidazole

• If client can’t abstain from alcohol

Before & AfterTreatment with Metronidazole

• Probing depth of 6 mm

• Tissue shrinkage & recession

Before & After Treatment with Metronidazole

• 6 mm probing depths • Surgery has not been required

Metronidazole

• Some evidence of bone gain – client 2.5 years after initial debridement and use of metronidazole

Metronidazole

• Dosage:– 250 mg tid for 7-10 days– 500 mg bid for 1-2 weeks

• Doxycycline– 100 mg per day or BID

• Metronidazole and amoxicillin or Augmentin– 250 mg (of each) TID for 7-10 days

Arestin

• Clinical use:– Periodontitis with pockets 5 mm

• How supplied:– Box containing 2 trays each containing 12

cartridges– Cartridge contains 1 mg of minocycline

(semisynthetic tetracycline derivative) microencapsulated in Poly dry powder

– Cartridge inserted into a cartridge handle

Arestin

• Preparing for Arestin

Premeasured, premixed, no refrigeration necessary

Arestin

• Mechanism of action:– Broad spectrum– Bacteriostatic– GCF levels maintained at high levels for at

least 14 days

Arestin

• Application:– Insert tip to base of periodontal pocket

– Expel powder into pocket

– Bioadhesive microspheres activate & adhere on contact with moisture

– Cartridge contains enough Arestin for one periodontal pocket

– Clinical trials: 30 sites treated in less than 10 minutes

– Dressings or adhesives not required

Arestin

• Adverse effects:– Headache– Pain– Mouth ulceration– Slu syndrome– Stomatitis

Arestin

• Client instructions:– Do not eat hard or sticky foods for 1 week– Postpone brushing for 12 hours– Do not use interproximal cleaning aids for 10

days

Arestin

• Clinical efficacy:– 27,000 sites treated, n=748

Arestin

• Clinical efficacy:– Arestin with debridement demonstrated 27%

greater pocket reduction in molars compared to debridement alone

• Mean reduction of 2 mm (pockets 7 mm +)

– Effective in furcations