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Adjunctive and Prophylactic Use of Antibacterial Agents in Dentistry

Course Number: 475

Prophylactic Antibacterial Chemotherapy

A significant percentage of antibacterial agents are putatively prescribed by dental practitioners for the prevention of infection. In general, when an effective antibacterial agent is used to prevent infection by specific bacteria or to eradicate them immediately or soon after they have become established, the strategy is frequently successful. However, prophylactic antibacterial chemotherapy in dentistry should be limited to the prevention of those infections that are proven or strongly suspected to be procedure-specific.

Prevention of Surgical-site Infection in Patients Undergoing Tooth Extractions

Tooth extraction is the indicated therapy for teeth deemed non-restorable. However, there is no evidence to support the prophylactic use of antibacterial agents in association with the extraction of non-restorable teeth.120 Another common reason for tooth extraction is poorly aligned or impacted third molars.

Antibacterial drugs administered just before and/or just after third molar extractions do reduce the risk of infection and dry socket, but there is no evidence that antibacterial agents prevent pain, fever, swelling, or trismus. The number needed to treat (NNT) to prevent one individual from having an extraction-related infection was estimated to be 19.120 However, the practice of administering a prophylactic antibacterial agent contributes to adverse drug effects, including the likelihood of bacterial drug resistance. Consequently, antibacterial agents given to healthy people in association with third molar extractions to prevent infection may cause more harm than benefit, both to patients and the community at large.120

Prevention of Surgical-site Infection in Patients Undergoing Placement of Dental Implants

Bacteria introduced during the placement of dental implants can lead to infection and implant failure. A recent critical review of 3 randomized double-blinded trials assessing 711 patient (1225 implants) revealed no statistically significant evidence to support the use of routine prophylactic antibacterial agents to reduce the risk of implant failure.121

In one of the studies assessed, the use of amoxicillin 2 g administered 1 hour preoperatively reduced the failure rate of dental implants placed under ordinary conditions; however the improvement was statistically insignficant.121 The number needed to treat (NNT) to prevent one individual from having an implant failure was estimated to be 33. Given the potential for adverse drug events and the contribution to antibacterial resistance, the authors questioned the use of prophylactic antibacterial agents to reduce implant failure.121

Prevention of Infective Endocarditis in Patients Undergoing Dental Procedures

The American Heart Association (AHA) publishes a clinical practice guideline, with periodic updates, for the prevention of infective endocarditis in patients undergoing dental procedures.122 The 2021 update stratifies cardiac conditions as to the risk of developing endocarditis and the severity of associated morbidity. Due to its high adverse effect risk, clindamycin is no longer recommended as a prophylactic agent. Only patients with the highest-risk of adverse outcome from endocarditis (Table 4) should be considered for antibacterial prophylaxis prior to dental procedures that involve manipulation of gingival tissue or the periapical region of teeth or perforation of the oral mucosa (Table 5).122

Table 4. Conditions Associated with the Highest Risk of Adverse Outcome from Endocarditis for Which Antibacterial Prophylaxis is Reasonable.122

  • Prosthetic cardiac valve or material.
    • Presence of cardiac prosthetic valves.
    • Transcatheter implantation of prosthetic valves.
    • Cardiac valve repair with devices, including annuloplasty, rings, or clips.
    • Left ventricular assist devices or implantable heart.
  • Previous infective endocarditis.
  • Congenital heart disease (CHD).
    • Unrepaired cyanotic CHD, including palliative shunts and conducts.
    • Completely repaired congenital heart defect with prosthetic material or device, whether placed by surgery or by catheter intervention, during the 6 months after the surgery.
    • Repaired CHD with residual defects at the site or adjacent to the site of a prosthetic patch or prosthetic device.
    • Surgical or transcatheter pulmonary artery valve or conduit placement such as Melody valve and Contegra conduit.
  • Cardiac transplantation recipients who develop cardiac valvulopathy.

In situations where no chemoprophylaxis was given, but in which unexpected bleeding occurred, the institution of antibacterial therapy within 2 hours is recommended. Patients at risk already taking an antibacterial agent should be prescribed one of the drugs from a different class recommended for chemoprophylaxis. For patients undergoing sequential care, Clinicians should allow at least 10 days (ideally 4 weeks) between appointments to reduce the risk for the development of resistant organisms.122

Table 5. Antibacterial Prophylaxis before Procedures that Involve Manipulation of Gingival Tissue, Periapical Region of Teeth, or Perforation of the Oral Mucosa.122

SituationAgentRegimen: single dose, 30-60 minutes before procedure
Patient not allergic to β-lactams AND able to take oral medicationsAmoxicillin2.0g, PO50mg/kg, PO
Patient not allergic to β-lactams BUT unable to take oral medicationsAmpicillin2.0g, IM or IV50mg/kg, IM or IV
Cefazolin or Ceftriaxone1.0g, IM or IV50mg/kg, IM or IV
Patient allergic to β-lactams AND able to take oral medicationsCephalexin*†2.0g, PO50mg/kg,PO
Azithromycin or Clarithromycin500mg, PO15mg/kg < 45kg, PO  4.4mg/kg >45kg, PO
Doxycycline100mg, PO100mg, PO
Patient allergic to β-lactams AND unable to take oral medicationsCefazolin or Ceftriaxone1.0g, IM or IV50mg/kg, IM or IV

* Or other first- or second-generation oral cephalosporin in equivalent adult or pediatric dosing.
 Cephalosporins should not be used in an individual with a history of anaphylaxis, angioedema, or urticaria with penicillin or ampicillin.

Prevention of Orthopedic Implant Infection in Patients Undergoing Dental Procedures

The American Academy of Orthopedic Surgeons (AAOS) in cooperation with the American Dental Association (ADA) published a clinical practice guideline, with periodic updates, for the prevention of orthopedic implant infection in patients undergoing dental procedures.

The 2012 AAOS-ADA Clinical Practice Guideline, which was developed using a systematic evidence-based process, provided no specific direction in managing individual patients and created confusion.123 In 2014, the American Dental Association Council of Scientific Affairs convened a panel of experts to develop an evidence based clinical practice guideline intended to clarify the issue.

The 2014 Panel found (1) no association between dental procedure-related transient bacteremia and prosthetic joint infection, and (2) no evidence that antibacterial agents administered prior to dental procedures prevent joint infarctions. The Panel also concluded that because of potential harmful effects of antibacterial agents such as allergic reaction and superinfections, the risks of antibacterial prophylaxis may exceed any benefit for most patients. Therefore, in general, the administration of antibacterial prophylaxis is not recommended for patients with prosthetic joints undergoing dental procedures.124

Prevention of Infection in Patients with Various Medical Conditions Undergoing Dental Procedures

A number of systemic conditions, e.g., neutropenia, asplenia, diabetes mellitus, end-stage renal disease, immunosuppression, systemic lupus erythematosus, and others are commonly cited as conditions that predispose a patient to bacteremia-induced infections. Evidence that a particular bacteremia-producing dental procedure caused a specific case of infection is circumstantial at best and no definitive, scientific evidence supports the use of prophylactic antibiotics.125-127 Most importantly, clinicians should amplify their efforts to ensure that all patients understand the critical importance of maintaining optimal oral health, which could serve to reduce the severity of both self-induced and treatment-induced bacteremia. In the absence of evidence or consensus on the issue, oral healthcare providers should weigh the benefits of antibacterial prophylaxis against the risks of ADEs, including the development of drug resistance.

Prevention of Surgical-site Infection in Patients Undergoing Open Reduction and Fixation of Mandibular Fractures

The benefit of pre- and intra-operative antibacterial chemotherapy when treating open mandibular fractures has long been established.128-130 More recently, a prospective randomized trial evaluated the efficacy of post-operative prophylactic antibacterial chemotherapy in association with open reduction and internal fixation of mandibular fractures and found no statistically significant benefit.131However, investigators concluded that tobacco and alcohol appear to be significant risk factors for post-operative infections.

Prevention of Surgical-site Infection in Patients Undergoing Head and Neck Oncology Surgery

The incidence of wound infection in patients undergoing head and neck oncology surgery has been reported to be as high as 87%, often with devastating consequences.132 Based on the best current evidence, it is recommended that prophylactic antibacterial agents, covering aerobic gram-positive cocci and gram-negative bacilli, and anaerobic bacteria be administered in association with clean and clean-contaminated head and neck oncology surgery.132 There is no evidence that prophylactic antibacterial agents offer any benefit in clean surgery for benign disease.