A cavity, or dental caries, is a hole in a tooth caused by decay from bacteria-produced acids. When a dentist diagnoses this damage, intervention is required because the tooth structure cannot regenerate or heal itself once the decay has broken through the enamel. Failing to treat a cavity allows decay to travel deeper into the tooth’s core, affecting increasingly sensitive and softer tissues. This delay transforms a localized, easily fixable issue into a complex infection, threatening the tooth’s survival and the patient’s overall health.
Progression from Enamel to Dentin
The earliest stage of a cavity involves decay progressing through the outer shell known as enamel. Enamel is the hardest substance in the human body, but once acids breach it, the decay advances toward the underlying layer called dentin. Dentin is softer and more porous than enamel, resembling a network of microscopic tubes that connect to the tooth’s nerve center. Once the decay reaches this layer, the destructive process accelerates considerably, allowing the cavity to expand much faster.
The exposure of the dentin layer causes the first noticeable symptoms, often manifesting as sharp sensitivity. Patients frequently report a brief, stinging pain when consuming substances that are very hot, cold, or sweet. At this point, the decay is usually still treatable with a simple dental filling, which involves removing the decayed material and sealing the hole. However, the structural integrity of the tooth is already compromised, and the window for this intervention is closing quickly.
Pulp Infection and Intense Pain
The decay continues its inward path, ultimately penetrating the dentin and reaching the pulp chamber, the innermost layer of the tooth. The pulp is a soft tissue containing the tooth’s nerves, blood vessels, and connective tissue. When bacteria and their toxins invade this space, the resulting severe inflammation is known as pulpitis.
Because the pulp is encased in the rigid walls of the tooth, the swelling from the infection increases pressure on the nerves. This results in pain that is often severe, spontaneous, and throbbing, frequently worsening at night or when lying down, and it may not respond well to over-the-counter pain medication. A simple filling is no longer a viable treatment option because the infection has contaminated the entire internal system of the tooth. To save the tooth, a procedure known as root canal therapy is required, which involves accessing the pulp chamber, removing the infected tissue, and sealing the root canals.
Spread of Infection Beyond the Tooth
If the infection within the pulp is not treated, the bacteria will travel out of the root tip into the surrounding jawbone. This leads to the formation of a periapical abscess, a localized pocket of pus at the end of the tooth’s root. An abscess creates intense pressure and can cause visible signs of infection, such as facial swelling, fever, and a persistent foul taste or discharge in the mouth.
The infection is no longer confined to the tooth, and the body’s attempt to contain it can lead to more serious complications. Bacteria from the abscess can spread into the bloodstream, a potentially life-threatening condition known as sepsis. In rare but serious cases, the infection can spread to the neck and floor of the mouth, causing Ludwig’s angina, which can obstruct the airway. The infection can also travel to the brain, leading to a brain abscess, which necessitates immediate medical intervention.
Increased Complexity and Cost of Intervention
The consequence of delaying treatment is an increase in the complexity and cost of the required dental procedure. A small cavity caught early requires a single, relatively inexpensive dental filling. This treatment is minimally invasive, requires little chair time, and preserves the maximum amount of natural tooth structure.
Allowing the decay to progress to the pulp stage necessitates a root canal, which is a more complex, multi-appointment procedure that is significantly more expensive. Following a root canal, the tooth often requires a crown to protect the now-brittle tooth structure from fracturing, adding considerably to the total expense. If the tooth is beyond saving, an extraction is required, followed by restoration options. Replacing a missing tooth with a dental implant, the preferred long-term solution, can cost many times more than the initial filling.