A tooth infection, often called a dental abscess, begins when bacteria invade the dental pulp, the innermost part of the tooth containing nerves and blood vessels. This invasion causes inflammation (pulpitis) and often leads to a periapical abscess—a pocket of pus forming at the tooth root tip within the jawbone. Many people worry if this localized infection can spread to neighboring teeth. This article addresses how a tooth infection spreads, differentiating between local effects and serious, body-wide risks.
Localized Spread and Adjacent Teeth
The anatomy of the mouth largely prevents a tooth infection from directly transferring bacteria into the nerve of an immediate neighboring tooth. Each tooth is a separate biological unit, encased by enamel and dentin, with its pulp chamber and root canals structurally distinct. However, the bacteria and pus do move through the surrounding bone and soft tissues.
Once the infection breaches the tooth’s root tip, it seeks the path of least resistance. This means the infection often spreads into the alveolar bone, the part of the jaw that holds the teeth, causing bone loss and creating the abscess. This localized inflammation and bone destruction can weaken the support structure for adjacent teeth.
The spread can also manifest as periodontal issues, damaging the ligament and gum tissue surrounding the neighboring tooth root. This process does not infect the adjacent tooth’s nerve, but it can contribute to localized gum disease or looseness in the adjacent tooth’s socket.
Systemic Risks of Untreated Dental Infections
An untreated dental infection can spread beyond localized oral structures into the rest of the body, leading to serious complications. Bacteria and pus can move through the jawbone, causing osteomyelitis, a deep bone infection.
A rapid pathway is soft tissue spread into the face and neck, often resulting in cellulitis, a bacterial skin infection. If the infection originates in the lower molars, it can descend into the deep fascial spaces beneath the tongue and neck, causing Ludwig’s angina. This is a medical emergency because the rapidly spreading swelling can obstruct the airway.
Bacteria can also enter the bloodstream (bacteremia), potentially leading to sepsis, a systemic inflammatory response that injures tissues and organs. From the bloodstream, bacteria can lodge in distant organs, causing infections like infective endocarditis, which affects the heart’s inner lining.
In severe cases, the infection can travel upwards through facial veins into the skull, potentially causing a brain abscess—a collection of pus within the brain tissue requiring immediate intervention. Infections in the upper back teeth also risk spreading into the maxillary sinuses, causing a specific type of sinusitis.
Halting the Spread Through Professional Treatment
Stopping the spread of a dental infection requires eliminating the source: the infected pulp tissue inside the tooth. Primary treatment options involve either saving the tooth or removing it. Root canal therapy saves the tooth by removing the infected pulp and nerves, cleaning the inner canal system, and then sealing it to prevent reinfection.
If the tooth structure is too compromised or the infection is too extensive, extraction is necessary to remove the source. For a large abscess, a dentist may perform an incision and drainage procedure to allow the built-up pus to escape, relieving pressure and reducing the bacterial load.
Antibiotics are prescribed when the infection spreads into soft tissues or when the patient has a weakened immune system. While antibiotics manage bacterial spread and prevent systemic complications, they do not eliminate the source within the tooth. Definitive treatment, such as a root canal or extraction, must follow for permanent resolution.