Abscesses - Etiology

When the balance between the root canal infection and the hostsdefence system results in favour of infection, a local spreading of the infection occurs and may result in abscess formation. This may take place spontaneously before any treatment has been started, or related to instrumentation of the canal. It is important to understand that over-instrumentation is not the sole prerequisite for a flare-up following commencement of treatment as some canal contents are usually introduced into the periapical area, despite proper instrumentation. Usually the abscess is caused by a mixed anaerobic infection with the additional presence of facultative bacteria.