Dental abscess

Dental abscesses are usually infected with viridans Streptococcus spp. or Gram-negative organisms. Treat dental abscesses in the first instance by using local measures to achieve drainage, with removal of the cause where possible. Antibiotics are not appropriate in cases where the infection is localised to the peri-radicular tissues as this indicates that the infection is being adequately managed by the immune system. Also, in these cases the abscess is mostly isolated from the circulation, resulting in very little antibiotic penetration. Antibiotics are only required if immediate drainage is not achieved using local measures or in cases of spreading infection (swelling, cellulitis, lymph node involvement) or systemic involvement (fever, malaise), all of which suggest that the immune system alone is not able to adequately manage the infection.

It is good practice to measure the temperature of patients with suspected bacterial infections, with temperatures <36^oC or >38^oC indicative of systemic involvement. However be aware that the absence of pyrexia does not preclude the prescribing of antibiotics if other signs and symptoms of spreading infection or systemic involvement are present.

Amoxicillin is usually effective at treating such infections, and is as effective as phenoxymethylpenicillin (penicillin V) but is better absorbed. The duration of treatment depends on the severity of the infection and the clinical response, but drugs are usually given for 5 days. However, do not prolong courses of treatment unduly because this can encourage the development of resistance. Severe infections include those cases where there is extra-oral swelling, eye closing or trismus but it is a matter of clinical judgement. Where there is significant trismus, floor-of-mouth swelling or difficulty breathing, transfer patients to hospital as an emergency. If the patient does not respond to the prescribed antibiotic, check the diagnosis and consider referral to a specialist.