A cavity, or tooth decay, is a damaged area on a tooth’s surface that forms when acids erode its hard outer layer. Cavities are a widespread dental issue, affecting people of all ages. If left unaddressed, these holes can expand, potentially leading to more serious dental problems.
Tooth Structure and Cavity Progression
Each tooth has a complex internal structure with several distinct layers. The outermost layer is the enamel, a highly mineralized and protective covering that shields the tooth from decay. Beneath the enamel is the dentin, a softer and more porous layer that forms the bulk of the tooth. At the tooth’s core is the pulp, a soft tissue containing nerves, blood vessels, and connective tissue.
Cavity formation begins when plaque bacteria produce acids that demineralize the enamel, creating weak spots. If this process continues, a hole eventually forms in the enamel. Once decay penetrates the enamel and reaches the dentin, its progression accelerates due to the dentin’s softer composition. If untreated, the decay continues inward, eventually reaching the pulp chamber, the innermost part of the tooth.
Symptoms and Nerve Damage
When a cavity reaches the tooth’s pulp, the nerve tissue within becomes inflamed, a condition known as pulpitis. This inflammation typically manifests as persistent pain, which can range from a dull ache to a sharp, throbbing sensation. Sensitivity to hot or cold temperatures often becomes pronounced and may linger for an extended period. Pain may also intensify when chewing or biting, and some individuals experience discomfort that is worse at night.
Pulpitis can be categorized into two main types: reversible and irreversible. Reversible pulpitis involves mild inflammation where the pulp can recover if the cause is treated. Symptoms like brief sensitivity to cold or sweets typically resolve once the irritant is removed. If the inflammation is more severe and the pulp cannot heal on its own, it progresses to irreversible pulpitis. In this stage, the nerve tissue often begins to die (pulp necrosis), leading to intense, spontaneous pain that may not subside.
Broader Health Implications
Beyond localized pain, an untreated cavity reaching the nerve can lead to broader health concerns. The infection within the pulp can spread beyond the tooth’s root tip, forming a dental abscess, a pocket of pus. This can cause swelling in the surrounding gum tissue, jaw, and face. An abscess may present with a foul taste, fever, and swollen lymph nodes.
If the infection is not addressed, it can extend into the jawbone, potentially causing a bone infection known as osteomyelitis. In severe instances, the infection can spread to the soft tissues of the face and neck, leading to cellulitis. A widespread infection from a dental abscess can enter the bloodstream, potentially leading to sepsis, a life-threatening condition where the body’s immune response to infection harms its own tissues and organs.
Remedies and Prevention
When a cavity has reached the nerve, the primary treatment to save the tooth is often root canal therapy. This procedure involves removing infected pulp tissue from inside the tooth, cleaning and disinfecting the inner canals, and then filling and sealing them to prevent further infection. A crown is typically placed over the treated tooth to restore its function and protect it. If the tooth is too severely damaged or the infection too extensive to be saved by a root canal, extraction may be necessary.
Preventing cavities from reaching this advanced stage involves consistent oral hygiene practices. This includes brushing teeth twice daily with fluoride toothpaste and flossing regularly to remove plaque and food particles. Regular dental check-ups and professional cleanings are also important, as they allow dentists to detect and treat cavities in their early stages before they progress deeper into the tooth. Maintaining a balanced diet and limiting sugary foods and drinks also helps protect tooth enamel and reduce cavity risk.