Dental caries, commonly known as cavities, result from the acidic waste products of oral bacteria feeding on sugars and starches. This process erodes the protective outer layers of the tooth, creating a hole. While small, early cavities are often painless and easily ignored, their progression is inevitable without intervention. Neglecting this initial damage sets off a chain of escalating consequences that affect the tooth, surrounding tissues, and overall health.
How Decay Progresses Through the Tooth
The initial stage of decay begins on the enamel, the hardest substance in the human body, which forms the outer shield of the tooth. Bacterial acids cause demineralization, weakening the enamel and eventually leading to a noticeable cavity. At this point, a simple dental filling can typically restore the tooth’s integrity and halt the decay.
If left untreated, the decay penetrates the enamel and reaches the underlying layer known as dentin. Dentin is softer and more porous than enamel, with microscopic tubules that lead directly toward the tooth’s center. Once the bacteria reach this layer, the decay accelerates rapidly. This exposure of the dentin often results in increased tooth sensitivity, especially discomfort when consuming hot, cold, or sweet foods and drinks.
Infection of the Pulp and Nerve
The continued erosion through the dentin eventually breaches the pulp chamber, the innermost part of the tooth. This central space contains the dental pulp, a collection of blood vessels, nerves, and connective tissue. The entry of bacteria into this sterile environment causes an infection and inflammation known as pulpitis.
The inflamed pulp swells within the rigid confines of the tooth structure, placing intense pressure on the delicate nerves. This is the stage where a severe, throbbing, constant toothache begins, which can radiate to the ear, jaw, or neck. As the infection progresses, blood flow is compromised, leading to the eventual death, or necrosis, of the pulp tissue. Intervention at this point typically requires a root canal treatment to remove the dead and infected tissue.
Abscess Formation and Jawbone Damage
Once the bacteria have destroyed the pulp tissue, they continue to multiply and travel down the tooth’s root canals. The infection exits the tip of the root and spreads into the surrounding tissues of the jawbone. This results in the formation of a periapical abscess, a localized pocket of pus and infection.
Paradoxically, the intense pain may temporarily subside once the pulp dies, leading to a false sense that the problem has resolved. However, the infection remains active and spreads beyond the tooth itself, causing symptoms like gum swelling, facial swelling, a foul taste in the mouth, or fever. The pressure from the accumulating pus can erode the surrounding bone structure, potentially leading to osteomyelitis, a bone infection. This advanced stage of infection often requires urgent treatment, including drainage of the abscess, root canal therapy, or surgical removal of the tooth.
Risks Beyond the Mouth
An uncontrolled dental infection represents a serious risk because the abscess is a reservoir of bacteria that can spread throughout the body. The infection can track through facial tissue spaces, potentially spreading to adjacent areas like the sinuses or the floor of the mouth. A severe and rapidly progressing cellulitis of the floor of the mouth, known as Ludwig’s Angina, is a rare but life-threatening complication that can obstruct the airway.
Bacteria from the abscess can also enter the bloodstream, a process called bacteremia, which can lead to more widespread infection. Though uncommon, this systemic spread can result in serious complications like a brain abscess or a generalized systemic infection known as sepsis.