A cavity, or dental caries, begins as bacterial damage to the tooth’s hard, protective outer structure. Bacteria convert sugars into acids, slowly dissolving the mineral content of the tooth surface. This acid erosion creates a hole that will not heal naturally, setting in motion a worsening infection if treatment is neglected. Addressing a cavity early is the only way to halt the progression of decay and preserve the tooth structure.
When Decay Reaches the Dentin
The initial decay progresses through the hard enamel layer, eventually breaking through to the underlying dentin. Dentin is a softer, yellowish tissue that forms the bulk of the tooth structure. This layer is far less mineralized than enamel, which allows the decay process to accelerate significantly once breached.
This transition often marks the first time a person experiences noticeable symptoms. Dentin contains thousands of microscopic fluid-filled tubes that lead directly to the tooth’s nerve. Exposure of these tubules creates a sensation of pain, often felt as a sharp, transient sensitivity. This occurs particularly when consuming hot, cold, or sweet foods and liquids.
The Spread of Infection to the Nerve
Continued neglect allows the bacterial infection to penetrate the dentin and reach the pulp chamber, which houses the dental pulp. The pulp contains the tooth’s nerve, blood vessels, and connective tissue. The arrival of bacteria triggers a severe inflammatory response called pulpitis.
Because the pulp is encased in the rigid walls of the dentin, swelling causes a rapid increase in internal pressure, compressing the nerve and blood supply. This pressure build-up results in severe, constant, throbbing pain. The pain often worsens at night or when lying down due to increased blood pressure in the head. At this stage, the damage is irreversible, meaning the pulp tissue cannot recover even if the decay is removed.
Developing a Dental Abscess
If the infection remains untreated, the bacteria will multiply and eventually kill the pulp tissue, causing the pain to temporarily subside as the nerve dies. However, the infection does not stop; it travels down the root canals and exits the tip of the root, spreading into the surrounding jawbone and gum tissue. This expansion of infection results in the formation of a pus-filled sac known as a periapical dental abscess.
Symptoms of an abscess include swelling of the gum near the tooth, facial swelling, a fever, and persistent pain when chewing or biting down. The body’s immune system is overwhelmed, and the infection can move beyond the localized area. This condition is a serious medical issue because the infection can spread into the deep fascial spaces of the head and neck.
Systemic Complications
The infection can lead to cellulitis, a rapidly spreading bacterial infection of the soft tissues, or even life-threatening systemic complications. In rare cases, bacteria can enter the bloodstream and cause sepsis, or travel to the brain via blood vessels, leading to conditions like cavernous sinus thrombosis. A foul taste may occur if the abscess drains through a small bump on the gum, but the underlying infection remains active even if pressure is relieved.
Emergency Treatments Required
Allowing a cavity to progress to an abscess necessitates immediate and invasive intervention, which is significantly more complex and costly than a simple filling. The initial step for a severe infection often involves draining the abscess to release the built-up pus and relieve pressure on the surrounding tissues. Antibiotics are usually prescribed to control the active bacterial infection, especially if there are signs of systemic spread like fever or facial swelling.
To save the tooth, root canal therapy is required. This procedure involves removing the infected pulp tissue from the interior of the tooth and sealing the space. If the infection has caused extensive bone loss or the tooth structure is severely compromised, the tooth may be deemed unsalvageable. In these cases, extraction becomes the only option to eliminate the source of the infection and prevent further complications.