Dental caries, commonly known as a cavity, is the physical destruction of tooth structure caused by acid erosion from bacteria. When food debris and sugars combine with oral bacteria, they produce lactic acid that demineralizes the hard outer shell of the tooth. A dental filling removes the decayed material and seals the remaining tooth structure to prevent further bacterial invasion. Delaying this procedure allows the decay to progress inward, transforming a small problem into increasingly severe health complications.
Progression Past the Enamel
The initial stage of decay occurs silently within the enamel, the hardest substance in the human body. Once the acid erosion breaches this outer layer, the decay penetrates the dentin, the layer immediately beneath the enamel. Dentin is softer and far more susceptible to rapid decay because it contains microscopic tubules that lead directly toward the tooth’s central nerve.
Patients often begin experiencing the first noticeable symptom: heightened sensitivity. This manifests as a sharp, temporary pain in response to hot, cold, or sweet stimuli, transmitted through the exposed tubules to the underlying nerve. At this stage, the decay is still treatable with a filling, though the procedure is more extensive than if detected earlier. If left untreated, the bacterial infection continues toward the innermost chamber of the tooth.
Infection Reaches the Tooth Pulp
If decay continues, bacteria reach the pulp, the central chamber containing the tooth’s nerves and blood vessels. Infection in this confined space causes inflammation known as pulpitis. Since the pulp is encased by rigid dentin, swelling compromises circulation, leading to irreversible damage and tissue necrosis. Symptoms progress from transient sensitivity to intense, persistent, throbbing pain that can awaken a person from sleep.
This stage represents a shift from a simple restorative procedure to a complex endodontic crisis. Treatment changes from a filling to either root canal therapy or extraction. Root canal therapy involves removing the infected pulp tissue, sterilizing the chamber, and sealing it. If the tooth structure is severely compromised or the infection is too advanced, extraction is the only remaining option to eliminate the source of bacteria.
Development of Abscesses and Spreading Infection
If the infected pulp remains untreated, bacteria multiply and exit the tip of the tooth root (apex), spreading into the surrounding jawbone. This leads to the formation of a periapical abscess, a localized pocket of pus. The pressure from this accumulation causes severe pain and can lead to noticeable swelling in the nearby gum tissue or the jaw.
The situation transitions from a localized dental issue to a serious medical emergency when the infection spreads beyond the tooth and jawbone. Bacteria from the abscess can enter the deep tissues of the head and neck, potentially causing cellulitis, a rapidly spreading bacterial skin infection. In rare cases, the infection can spread to the floor of the mouth, causing Ludwig’s angina, a life-threatening condition that can obstruct the airway. The bacteria may also enter the bloodstream, leading to sepsis, a widespread inflammatory response that can be fatal if not treated immediately.