A cavity, technically known as dental caries, represents the destruction of the tooth structure by acids produced by bacteria in plaque. This process begins with the demineralization of the hard outer layer, the enamel, and progresses inward toward the softer inner tissues. A cavity is a progressive condition that will not resolve or heal without dental intervention. Delaying treatment ensures the decay will deepen, transforming a simple issue into a much more serious problem that affects the entire tooth and potentially the body.
Increased Sensitivity and Dentin Erosion
The first noticeable consequence of an untreated cavity occurs when the decay breaches the hard enamel and reaches the underlying layer known as dentin. Dentin is not as dense as enamel and contains millions of microscopic tubes, called dentinal tubules, which connect directly to the nerve-filled pulp chamber.
When the protective enamel is lost, external stimuli like cold air, hot liquids, or sweet foods can cause the fluid within these exposed tubules to move rapidly. This fluid movement stimulates the nerves near the pulp, causing a sharp, short burst of pain known as dentin hypersensitivity. This pain is transient, quickly disappearing once the stimulus is removed, serving as an early warning sign that the decay has advanced. Because dentin is much less resistant to bacterial attack than enamel, the decay process accelerates significantly once this softer tissue is reached.
Severe Pain and Internal Nerve Infection
If the decay continues to progress through the dentin, the bacteria will eventually invade the pulp chamber, the innermost part of the tooth that houses the nerves and blood vessels. This invasion leads to inflammation and infection of the pulp tissue, known as irreversible pulpitis. Because the pulp is encased in the rigid structure of the tooth, the inflammation causes a painful buildup of pressure inside the chamber.
At this stage, the pain changes dramatically from transient sensitivity to a severe, constant, and throbbing toothache that may start spontaneously. The discomfort can linger after exposure to hot or cold temperatures, or even wake a person up at night, indicating the pulp tissue is damaged beyond healing. The pressure and infection often lead to the death of the nerve, a process called pulp necrosis. When this occurs, a simple filling is no longer sufficient; the tooth requires a root canal procedure to remove the infected tissue, or the tooth must be extracted entirely.
Abscess Formation and Systemic Spread
The infection does not stop once the nerve dies; the bacteria multiply and spread out of the root tip into the surrounding jawbone and gum tissue. This results in the formation of a periapical dental abscess, a localized pocket of pus. This stage is often accompanied by swelling in the jaw or face, tenderness, and sometimes the presence of a small, pus-filled bump on the gum line near the infected tooth.
A dental abscess is a serious infection that can destroy the supporting bone structure around the tooth, leading to eventual tooth loss. The primary concern is the risk of the infection spreading beyond the oral cavity. If the abscess does not drain, the bacteria can enter the bloodstream or surrounding soft tissues, potentially causing life-threatening complications.
Systemic spread can result in conditions like cellulitis, a serious bacterial skin infection, or, in rare cases, sepsis, a widespread inflammatory response that can lead to organ failure. For abscesses in the upper jaw, the infection can even spread into the sinuses. The development of an abscess transforms an easily treatable cavity into a major medical concern with escalating pain, expense, and health risks.