The main cause of pus in the gums from a dental abscess is a bacterial infection, according to BootsWebMD. This bacterial infection comes from poor oral hygiene that leads to a cavity, and then the infection grows into the soft tissues around the tooth.
An infected tooth that is not treated leads to the bacteria spreading into the gums and connective tissues. Pus collects at the site of the infection until the abscess drains. The drainage either occurs when the abscess ruptures or when an oral surgeon punctures it, notes BootsWebMD. Signs of a dental abscess include a cavity, swelling, tenderness, pus drainage and difficulty swallowing. Some abscesses may make it more difficult to swallow or even harder to breathe. Patients with an advanced infection may have nausea, fever and chills.
Dentists identify three types of dental abscesses, states Medical News Today. A gingival abscess occurs in the gums, while a periapical abscess is in the soft pulp of the tooth. A periodontal abscess begins in the supporting bone and ligaments of the tooth. If a dental abscess is not treated right away, surrounding bone tissue may become infected. Oral surgeons drain the pus, remove any teeth that are too infected and may reshape gum tissue.
Patients can prevent dental abscesses by brushing and flossing every day, explains BootsWebMD. Cavities that are repaired early may also prevent pus and abscesses. Patients may want to avoid using alcohol and tobacco to prevent oral infections.