Antibiotics typically prescribed in dental practice for some of the following purposes

• Treatment for acute odontogenic infections
• Treatment for non-odontogenic infections
• Prophylaxis against local infection in patients at risk (endocarditis and joint prostheses)
• Prophylaxis against local infection and systemic spread in oral surgery

Narrow-Spectrum Antimicrobial Agents Encountered in Dentistry 

Clindamycin 

• Bacteriostatic (bactericidal at higher doses) 
• Active against some aerobic gram +ve cocci (including Staph aureus, S. epidermidis, streptococci and pneumococci), some anaerobic gram –ve bacilli, many anaerobic gram +ve non–spore-forming bacilli, many anaerobic gram +ve cocci & clostridia.
• Indicated for the treatment of infections caused by susceptible microorganisms; used as a prophylactic antibiotic in high-risk patients allergic to penicillin for the prevention of both bacterial endocarditis and infections of total joint replacements

Metronidazole 

• Bactericidal 
• Active against most anaerobic cocci and both gram –ve bacilli and gram +ve spore forming Bacilli 
• Has been used as adjunct in treatment of periodontitis and ANUG; commonly co-prescribed with amoxicillin (combined use with amoxicillin or amoxicillin/clavulanic acid has not been approved by FDA)

Penicillin V Potassium 

• Bactericidal 
• Cell-wall synthesis inhibitor 
• Active primarily against gram +ve cocci (including S. aureus), gram +ve & gram –ve bacilli, spirochetes) 
• Use is limited to treatment of minor infections such as ulcerative gingivostomatitis and to the prophylaxis and continued treatment of streptococcal infections 

Amoxicillin

• Bactericidal 
• Active against many gram –ve & gram +ve organisms; not Effective against β lactamase–producing bacteria 
• Empirical antibiotic for oral infections, sinusitis & skin Infections; prophylactic antibiotic in high-risk patients for the prevention of bacterial endocarditis 

Amoxicillin + Clavulanic Acid 

• Bactericidal 
• Active against a wide spectrum of gram –ve & gram +ve organisms, including βlactamase producing bacteria 
• Used for the treatment of sinus, oral and respiratory infections 

Ampicillin

• Bactericidal 
• Active against many gram – ve and gram +ve organisms; not eff. against βlactamase–producing bacteria 
• Commonly used empirical antibiotic for oral infections, sinusitis & skin infections. Prophylactic antibiotic in high-risk patients unable to take oral medication for the prevention of bacterial endocarditis 
• Broad-Spectrum Antimicrobial Agents Encountered In Dentistry – Cefadroxil, Cefazolin, Cephradine, Azithromycin, Clarithromycin, Erythromycin, Tetracycline (Doxycycline, Minocycline) 

Antibiotic prophylaxis NOT required for 

• Routine anesthetic injections though non-infected tissue 
• Taking dental radiographs 
• Placement of removable prosthodontic appliances 
• Placement / adjustment of orthodontic appliances 
• Placement of orthodontic brackets 
• Shedding of deciduous teeth 
• Bleeding from trauma to the lips / oral mucosa 

Oral cavity is intensely colonized by bacteria. The maximum concentration found in bacterial plaque (~ 1011 - 1012 microorganisms per gram of wet weight) and abundant bacteria is present on back of tongue / cheek / palatal mucosa. Up to 200 different bacterial species isolated from a single oral cavity. Thus, antibiotics sould be prescribed according to the clinical scenario, the treatment required and patient’s systemic condition.

Article by Dr. Siri P. B.