This paper provides a review of current antibiotics usage in dentistry and highlights the changes in the use of these drugs over the past 40 years.
Prophylactic use of antibiotics
This is perhaps the most significant change that has affected dental practice over the past 40 years, especially chemoprophylaxis to prevent dental-induced procedures causing infective endocarditis in at risk patients. This topic has been the subject of much debate and controversy and, of course, great concern to dental professionals. Evidence was accumulating that penicillins (the drug of choice in dealing with dental-induced bacteraemia) afforded little or no benefit for this indication.2 Likewise, it was estimated that adverse effects from the penicillins, especially anaphylaxis, was more likely to kill the patient than if they contracted infective endocarditis.3 There was also debate over what procedures needed cover and the categories of patients at risk.
A breakthrough in this debate was provided by Roberts,4 who demonstrated that everyday dental events, such as toothbrushing, flossing and even chewing, could produce bacteraemia of similar magnitude to that generated from a single tooth extraction.
For many years, the British Society for Antimicrobial Chemotherapy (BSAC) published guidelines on antibiotic prophylaxis for dental procedures.5 Only three categories of patients were considered at risk from dental-induced bacteraemia, notably:
Those with a previous history of infective endocarditis;
Patients with prosthetic heart valves; and
Those with a surgically constructed systemic or pulmonary shunt.
The BSAC did consider scrapping antibiotic prophylaxis completely for dental procedures in so-called at risk patients, but this was considered a step too far.
It is against this background of confusion and controversy that several bodies lobbied NICE to investigate whether antibiotic prophylaxis was necessary for ‘at risk patients’ prior to certain dental procedures. NICE published their guidelines in 2008 and recommended the complete cessation of antibiotic prophylaxis for all patients undergoing dental procedures.6 These guidelines were reinforced by the Chief Dental Officer and the British National Formulary.
Despite the NICE guidelines, cardiologists still expressed concern that certain patients were at risk from dental-induced bacteraemia and continued to recommend cover. Likewise, other bodies, such as the American Heart Association and the European Society of Cardiology, still continued to recommend cover for certain categories of patient. The NICE guidelines did afford an opportunity to consider whether antibiotic prophylaxis reduced the prevalence of infective endocarditis. Data on this topic were reviewed by Thornhill and workers in 2011,7 and they showed that the cessation of antibiotic prophylaxis for dental procedures has not produced an increase in the incidence of infective endocarditis cases from May 2006 to May 2010. The continued monitoring of the incidence of infective endocarditis would further vindicate the NICE guidelines.
Other categories of patients where antibiotic prophylaxis has been recommended
Controversy still remains concerning whether patients who have been fitted with joint prostheses should be prescribed antibiotic prophylaxis prior to their dental treatment, despite there being little or no evidence to support the usage of these drugs or their benefit in such patients. Most of the pressures come from orthopaedic surgeons, despite several reviews in the literature to refute their claims.8 It is worth reiterating the recommendations from the BSAC which is quoted in the latest issue of the BNF: ‘patients with prosthetic joint implants, including total hip replacement do not require antibiotic prophylaxis for dental treatment. The working party considers it unacceptable to expose patients to the adverse effects of antibiotics when there is no evidence that such prophylaxis is of any benefit, but those who develop any undercurrent infection require prompt treatment with antibiotics to which the infecting organisms are sensitive’.
Despite this clear statement, there exists a cohort of orthopaedic surgeons that still advise their patients that antibiotic cover is required. This can lead to conflict between dentist, his/ her patient and orthopaedic colleagues. In such circumstances, it is often the patient's regard for the advice from orthopaedic surgeons which clouds judgement and many patients end up receiving antibiotics despite evidence to the contrary. This particular topic does seem a further area for NICE to consider and issue guidelines upon.
A further category of patients is those who are immunosuppressed and those with indwelling intraperitoneal catheters. Again, advice from the BSAC published in the BNF seems totally relevant: ‘patients who are immunosuppressed, including transplant patients, and patients with indwelling intraperitoneal catheters do not require antibiotic prophylaxis for dental treatment provided there is no other indication for prophylaxis. The working party has commented that there is little evidence that dental treatment is followed by infection in immunosuppressed and immunodeficient patients, nor is there evidence that dental treatment is followed by infection in patients with indwelling intraperitoneal catheters’.
Prophylactic use of antibiotics for dental procedures
There has been much interest in the prophylactic use of antibiotics prior to certain dental procedures to prevent post-operative complications. The two procedures that have received the most attention for such antibiotic usage are third molar surgery and the placement of dental implants.
The value of prophylactic antibiotics prior to third molar surgery was reviewed in 2005.9 The authors recognized that this particular indication for antibiotics was controversial. However, once the evidence was reviewed, they concluded that there was no justification for routine antibiotic prophylaxis for third molar surgery.
The position regarding the value of such antibiotic usage prior to the placement of dental implants is slightly more controversial. A Cochrane systematic review published in 201010 evaluated four randomized controlled trials which assessed the benefit or otherwise of either 1g or 2g of amoxicillin versus placebo prior to implant placement. The analysis concluded that there was some evidence to suggest that 2g amoxicillin given orally one hour before implant placement significantly reduced implant failure. This criterion only applied when implants were placed in ordinary conditions. The review commented that the benefits of post-implant placement antibiotics remained unknown.
A more recent review11 considered the value of no, pre- and post-antibiotic prophylaxis on implant survival. Over 11,400 implant placements were evaluated in this review. The findings showed that, when no antibiotics were prescribed, implant success rate was 92%. This compared to a success rate of 96% when antibiotics were used pre-operatively and a 97% success rate when these drugs were used both pre- and post-implant placement. Whilst some slight differences in success rates were noted between the different options, these were small and led the authors to conclude that there was no benefit from the use of antibiotic prophylaxis in low and moderate risk implant patients.
Both reviews have come to different recommendations, with the Cochrane study showing a benefit for the prophylactic use of 2g amoxicillin prior to implant placement, whereas the later review refutes this recommendation. It is worth noting that the Canadian paper involved a much higher number of patients and implant placements when compared to the Cochrane review. This does add more power to the argument on the value of antibiotics on implant survival. Whilst the jury may still be out on this particular use of antibiotics, it should be emphasized that antibiotic usage as part of implant placement should not be a substitute for careful patient selection or the surgical technique.
Antibiotics in the management of periodontal disease
A topic that has been extensively researched since the 1973 Update article has been the use of antibiotics in the management of periodontal disease. This area has been driven by a greater understanding of the role of various bacteria in the pathogenesis of periodontal destruction.
Metronidazole still remains the treatment of choice for acute necrotizing ulcerative gingivitis (ANUG), but this drug has also been investigated in the management of a variety of other periodontal conditions. Other agents also evaluated include the tetracyclines, the combination of amoxicillin and metronidazole, azithromycin and clindamycin.
The nature of periodontal pockets has also led to a plethora of antibiotic products which can be placed in this location. These agents, referred to as controlled release devices or local delivery systems, are placed in a periodontal pocket after local debridement.
Local or systemic antibiotics should never be used as the sole treatment for periodontitis.12 Any benefits derived from antibiotic treatments alone are minimal and short term.
Antibiotics in the management of periodontitis
This is a controversial area, but evidence suggests that the adjunctive use of systemic antibiotics provides additional benefits over scaling and root planing alone. The benefits are more obvious in cases of advanced chronic periodontitis.13 Most of the studies evaluated in this review followed up patients for a period of 6–12 months. Thus long-term benefits for the adjunctive use of antibiotics are still open to question.
For the surgical management of periodontitis the adjunctive use of antibiotics is more equivocal. The recent systemic review13 concluded that there was insufficient data to determine whether such antibiotic usage was of any benefit.
Antibiotics in the management of aggressive periodontitis
This form of periodontal disease is characterized by the presence of high levels of Aggregatibacter actinomycetemcomitans (Aa) and/or Porphyromonas gingivalis (Pg). Adjunctive antibiotics have been shown to be useful in either eradicating or suppressing these bacteria. The combination of amoxicillin and metronidazole appears to be the most useful adjunctive antibiotic regimen for this condition.14 Six clinical trials supported this comment. In all of these trials, the combination of amoxicillin and metronidazole was used as an adjunct to full-mouth scaling and root planing. Other systemic antibiotics that have been shown to be of value in the adjunctive management of aggressive periodontitis include azithromycin and doxycycline.15,16
The timing of the adjunctive antibiotic therapy in relation to the treatment of the disease is also important. Systemic dosing should start on the day of root surface instrumentation and, ideally, the instrumentation should be completed within 7 days.13
Antibiotics in the treatment of peri-implantitis
The management of peri-implantitis remains a controversial topic, especially with regards to the use of adjunctive antibiotics. A systematic review has been conducted on evaluating the efficacy of both local and systemic antibiotics in the adjunctive management of peri-implantitis.17 Local antibiotics have been used in this condition as adjuncts to mechanical debridement and other chemical plaque control agents. Although there were some benefits from the adjunctive use of local antibiotics in the management of peri-implantitis, the benefits were described as ‘moderate’. The current data available for the use of systemic antibiotics in the management of peri-implantitis is regarded as insufficient to allow for any firm specific recommendations. Thus there appears to be a need for more clinical trials to evaluate the benefit or otherwise of antibiotics in the management of peri-implantitis.
