Antibiotic Prescribing in Dentistry: When to Prescribe and When Not To

A patient attends with a swollen face, a non-vital lower molar and a fluctuant buccal swelling. They are prescribed amoxicillin and sent away with a review appointment in five days.

This is one of the most common errors in dentistry, and it is an error of principle rather than of drug choice. The source of the infection is a necrotic pulp and a collection of pus. Neither is addressed by an antibiotic.

Dentistry accounts for a meaningful share of antibiotic prescribing in most healthcare systems, and a substantial proportion of it is unnecessary. This guide covers when antibiotics are genuinely indicated, when they are not, and how to prescribe well when they are.

Always work from current national guidance, which varies between countries and is updated periodically. The principles below are stable; the specific regimens are not.

Dental infections are nearly always the consequence of a localised source - a necrotic pulp, a periodontal pocket, a pericoronal flap, an infected socket. The definitive treatment is removal of that source and drainage of pus.

Antibiotics are an adjunct. They are indicated when infection has spread beyond the local site, when the patient shows systemic involvement, or when the host cannot contain the infection unaided.

Expressed as a working rule: if you can drain it, drain it. An antibiotic prescribed instead of drainage delays definitive treatment and allows the infection to progress while giving both clinician and patient false reassurance.

Symptomatic irreversible pulpitis. This is inflammation, not infection. The treatment is pulp extirpation or extraction, and analgesia. Antibiotics do not relieve pulpitis.

Acute apical periodontitis without systemic involvement, where drainage through the canal or extraction resolves it.

A localised fluctuant abscess that can be drained, in a patient who is systemically well.

Chronic sinus tract, where the infection is already draining.

Alveolar osteitis, or dry socket. This is a disturbance of healing, not an infection. Irrigation, dressing and analgesia.

Pericoronitis confined to the pericoronal tissues, without spread or systemic signs, treated by irrigation under the operculum, debridement and management of the opposing tooth.

Chronic periodontitis, which is managed by mechanical debridement. Systemic antibiotics have a limited adjunctive role in specific situations, not as routine therapy.

A patient who requests antibiotics for any of the above.

Spreading infection with cellulitis, a diffuse rather than localised swelling.

Systemic involvement: fever, malaise, lymphadenopathy, raised temperature.

Trismus, dysphagia, dysphonia, or any sign of airway compromise - these are urgent referrals as well as antibiotic indications, not conditions to manage with a prescription and a review in a week.

Infection in an immunocompromised patient, including poorly controlled diabetes, and patients on immunosuppressive therapy.

Necrotising periodontal diseases. Acute osteomyelitis. Severe pericoronitis with spread beyond the pericoronal tissues.

Some surgical procedures in specific circumstances, and some dental trauma presentations such as avulsion and replantation.

In all of these, the antibiotic accompanies definitive local treatment. It does not replace it.

This is the area where national guidance differs most, and where you must use your own country's recommendations.

Infective endocarditis prophylaxis has been progressively narrowed over the past two decades. Several countries now recommend it only for a small group at the highest risk - such as patients with prosthetic valves or prosthetic material used for valve repair, previous infective endocarditis, and certain congenital heart conditions - and only for defined dental procedures involving manipulation of gingival tissue, the periapical region, or perforation of the oral mucosa. Other countries have adopted stricter or more permissive positions.

What is consistent everywhere is the emphasis on oral health maintenance. The cumulative bacteraemia from everyday chewing and brushing in a mouth with untreated periodontal disease substantially exceeds that from a single dental procedure. Keeping an at-risk patient periodontally healthy matters more than the prophylactic dose.

Prosthetic joint prophylaxis is no longer routinely recommended by most major bodies. If an orthopaedic surgeon requests it for a particular patient, that request should be documented along with who made it.

Where prophylaxis is indicated, it is a single dose shortly before the procedure, not a course.

Where antibiotics are indicated, the common first-line choice for odontogenic infection is a penicillin, with the addition of metronidazole where anaerobic involvement is prominent or the response is inadequate.

In reported penicillin allergy, alternatives include clindamycin or a macrolide, depending on national guidance.

Two points about penicillin allergy are worth making, because they affect prescribing quality. A large majority of patients labelled penicillin-allergic are not, in fact, allergic on formal testing - the label is often inherited from a childhood rash of uncertain cause. And the alternatives carry their own risks, clindamycin being notably associated with Clostridioides difficile colitis. Taking a proper allergy history - what happened, how soon, how was it treated - and encouraging formal assessment where the history is vague is a genuine contribution to patient care.

Prescribe the shortest effective course. Review the patient. If they are not improving, the problem is usually that the source has not been dealt with, not that the antibiotic was the wrong one.

Antimicrobial resistance is driven by volume of prescribing, and dentistry contributes to it.

Four practical changes make the largest difference.

Provide same-day drainage or pulp extirpation wherever your schedule allows. Most unnecessary dental antibiotic prescribing happens because there was no time to treat the tooth. Protecting emergency slots in the appointment book is an antimicrobial stewardship intervention.

Explain to patients why an antibiotic is not indicated. Most accept it when the reasoning is given; refusal without explanation is what generates pressure.

Prescribe analgesia properly. A patient in pain who is given an antibiotic and inadequate analgesia will return and will be prescribed more.

Audit your own prescribing. Most clinicians who examine their last fifty prescriptions find a proportion they would not write again.

Our Online Dental Pharmacology Course and Dental Pharmacology Test Series cover prescribing, drug interactions and the pharmacology examined in licensing examinations. Our Medical Emergency Course covers anaphylaxis and the management of adverse drug reactions.

Related reading: our articles on managing dental emergencies, why root canals fail, and the 2017 periodontal classification.