[I'm going to the dentist: antibiotic as a prevention or as a treatment?].

Odontogenic infections account for 10% of all antibiotic prescriptions in Spain. Despite the frequency and importance of these infections, there is often confusion between prophylaxis and treatment. The oral cavity is a complex ecosystem made up of over 500 bacterial species. It is essential to take the medical history, examine each infection, and know about previous illnesses that could change our therapeutic and/or prophylactic attitude. The use of prophylaxis with antibiotics in patients at risk of infective endocarditis has been accepted for many years. Nowadays this is being restricted, and in many cases the risks of taking preventive antibiotics outweigh its benefits. There are no serious studies to determine the best antibiotic and its dosage, thus the Spanish consensus guidelines have to be followed. It is not known how the misuse of antibiotics influences bacterial resistance, not only on pathogen strains, but also on the common oral flora.