When an abscess has penetrated to the oral cavity and a sinus tract has been formed, no further treatment is required to establish drainage into the oral cavity.
Fluctuating abscesses that have not perforated the mucosa should be drained by incision to allow drainage of the pus. Drainage should be established and maintained usually for 2 to 4 days, e.g. with a piece of sterile rubber dam that is sutured in mucosa for stability.
The treatment of choice is to start the endodontic treatment by routine methods; ideally, chemo-mechanical preparation is completed at the first visit, and the canal filled with calcium hydroxide.
Systemic antibiotics are not routinely prescribed for abscesses. Indications for antibiotic treatment include certain risk patients (recommendations vary in different countries and local recommendations should be followed), general symptoms such as fever or reduced resistance, a potentially dangerous location of the infection, and spreading infections.