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.118 Another common reason for tooth extraction is poorly aligned or impacted third molars. The infection rate after third molar extraction is about 10%.118 In debilitated or immunocompromised patients, the infection rate may be as high as 25%.118

Antibacterial drugs administered just before and/or just after third molar extractions do reduce the risk of infection, pain, and dry socket, but there is no evidence that antibacterial agents reduce fever, swelling, or trismus. The practice also 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.118

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 critical review of the literature identified four randomized controlled clinical trials, with a follow up of at least 3 months, comparing the efficacy of various prophylactic antibacterial regiments versus no antibiotics in patients undergoing dental implant placement.119 The implant failure rate among patients not receiving antibiotics was 5%.119

There is some evidence to suggest that amoxicillin 2 g administered 1 hour preoperatively significantly reduces the failure rate of dental implants placed under ordinary conditions.119 The number needed to treat (NNT) to prevent one individual from having an implant failure is 33. No significant adverse drug effects were reported, although the issue of antibacterial drug resistance was not addressed. There is no evidence that postoperative antibacterial agents are beneficial.119

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.120 The 2007 guideline stratifies cardiac conditions as to the risk of developing endocarditis and the severity of associated morbidity. Only patients with the highest-risk of adverse outcome from endocarditis (Table 4) should be considered for antibacterial prophylaxis prior to invasive dental procedures (Table 5).120

Table 4. Conditions Associated with the Highest Risk of Adverse Outcome from Endocarditis for Which Antibacterial Prophylaxis is Reasonable.120
  • Prosthetic cardiac valve or prosthetic material used for cardiac valve repair.
  • 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, weather 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, which inhibit endothelialization.
  • Cardiac transplantation recipients who develop cardiac myopathy.

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. Clinicians should allow at least 9-14 days between appointments to reduce the risk for the development of resistant organisms.

Table 5. Antibacterial Prophylaxis before Procedures that Involve Manipulation of Gingival Tissue, Periapical Region of Teeth, or Perforation of the Oral Mucosa.120

SituationAgentRegimen: single dose, 30-60 minutes before procedure
Patient not allergic to β-lactams
able to take oral medications
Amoxicillin2.0g, PO50mg/kg, PO
Patient not allergic to β-lactams
unable to take oral medications
Ampicillin2.0g, IM or IV50 mg/kg, IM or IV
Cefazolin or
1g, IM or IV50 mg/kg, IM or IV
Patient allergic to β-lactams
able to take oral medications
Clindamycin600mg, PO20mg/kg, PO
Azithromycin500mg, PO15mg/kg, PO
Patient allergic to β-lactams
unable to take oral medications
Clindamycin600mg, IM or IV20mg/kg, IM or IV

Prevention of Orthopaedic 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 orthopaedic 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.121 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.122

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.123-125

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.126-128 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.129 However, 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.130 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.130 There is no evidence that prophylactic antibacterial agents offer any benefit in clean surgery for benign disease.