Dental decay, commonly known as a cavity, is a progressive bacterial disease affecting the hard structure of the tooth. It begins when bacteria in the mouth produce acids that erode the tooth’s outer layers. Unlike an injury, tooth decay cannot heal itself naturally once a physical hole has formed. Ignoring a cavity allows this destruction to continue unchecked, leading to increasingly complex and severe health outcomes.
From Enamel Damage to Sensitivity
The earliest stage of a cavity involves the demineralization of the tooth’s outermost layer, the enamel. Bacteria in plaque metabolize sugars and starches, releasing acid as a byproduct. This acid dissolves the mineral content of the enamel, initially creating a white spot lesion that is often asymptomatic.
If this process is not arrested through improved hygiene or fluoride treatment, the enamel structure eventually breaks down, forming a true cavity. Once the decay breaches the enamel, it quickly penetrates the underlying layer called dentin. Dentin is softer and contains millions of microscopic tubules that lead directly to the tooth’s pulp chamber.
The exposure of these tubules to the oral environment causes the first noticeable symptom: tooth sensitivity. Patients often experience a sharp, fleeting discomfort when consuming hot or cold beverages, or sweet foods. This sensitivity signals that the protective outer barrier has been compromised and the decay is advancing toward the tooth’s nerve center.
Deep Infection and Abscess Formation
Continued neglect allows bacteria to burrow through the dentin and reach the innermost core of the tooth, the dental pulp. The pulp contains the tooth’s blood vessels, connective tissue, and nerves. When bacteria invade this space, it results in inflammation known as pulpitis, causing intense, persistent pain.
The confined nature of the pulp chamber means that swelling increases pressure on the nerve tissue, which is the source of the severe discomfort. Eventually, the infection and pressure overwhelm the pulp’s ability to heal, leading to the death of the nerve tissue. Paradoxically, this nerve death may cause the pain to temporarily subside, falsely suggesting the problem has resolved.
The infection does not stop; it travels through the root canal system and exits the tip of the tooth’s root. Once outside the tooth, the bacteria trigger an inflammatory response in the surrounding jawbone, forming a dental abscess—a localized pocket of pus. An abscess requires immediate professional intervention, typically a root canal procedure to clean out the infected tissue or, if the tooth is irreparable, extraction.
Systemic Health Risks and Tooth Loss
A dental abscess is a localized infection with the potential for widespread consequences, as bacteria can enter the bloodstream or surrounding facial tissues. This spread can lead to serious medical conditions, such as cellulitis, a rapidly spreading bacterial infection of the soft tissues of the face and neck. A more severe complication is Ludwig’s angina, a life-threatening form of cellulitis that causes swelling on the floor of the mouth and neck, potentially obstructing the airway.
Bacteria from the abscess can also travel through the blood vessels, resulting in conditions like cavernous sinus thrombosis, an infection of the blood clot in the brain’s venous sinuses. Chronic oral infection contributes to systemic inflammation, which has been linked to an increased risk of heart problems, including infective endocarditis, where bacteria colonize the heart valves. A persistent infection also makes managing chronic conditions like diabetes more difficult.
If the decay reaches the point where the tooth structure is severely compromised, the tooth becomes non-restorable, resulting in tooth loss. The loss of a tooth causes adjacent teeth to shift out of alignment and can lead to bone resorption, where the jawbone beneath the missing tooth begins to deteriorate from lack of stimulation. This structural change affects the overall bite and the stability of neighboring teeth, necessitating further intervention.
Escalation of Treatment and Cost
The financial and procedural burden of addressing a neglected cavity increases with each stage of decay progression. Treating a small, early-stage cavity requires a simple dental filling, a quick and affordable procedure. The average cost for a single filling may range from $150 to $400, depending on the material and location.
Once the decay has reached the pulp and caused an abscess, treatment escalates to a root canal procedure, which is significantly more complex and time-consuming. A root canal alone can cost between $700 and $1,500. This often requires a subsequent crown to protect the now-brittle tooth structure, adding another $800 to $1,500 to the total cost.
If the tooth is ultimately lost due to irreparable damage, replacement options, such as a dental implant or a bridge, represent the highest financial investment. Dental implants, including the abutment and crown, can cost several thousand dollars per tooth. Delaying care transforms a manageable, inexpensive procedure into a painful, complex, and costly series of interventions.