A root canal, or endodontic therapy, is a procedure designed to eliminate infection and inflammation from the innermost part of a tooth, known as the dental pulp. This pulp contains nerves, blood vessels, and connective tissue. When decay or trauma allows bacteria to invade this sterile space, an infection results. Once bacteria have colonized the pulp chamber, the pulp tissue will inevitably die, a condition called necrosis. Delaying treatment is not a viable option because the infection will not resolve on its own.
The Immediate Progression of Untreated Infection
The immediate consequence of leaving a necrotic pulp untreated is the development of a periapical abscess, a localized pocket of pus that forms at the tip of the tooth root. This abscess forms as the body’s immune system attempts to contain the bacterial infection that has spread into the surrounding jawbone. The buildup of pus creates intense pressure, which is often the source of the severe, throbbing pain that characterizes a dental infection.
This pressure causes localized bone destruction around the root tip, visible on dental X-rays as a dark area called a radiolucency. The body may try to drain the infection by creating a small channel through the gum tissue, resulting in a pimple-like bump called a fistula or “gum boil.” While the rupture of this abscess can temporarily relieve the pressure and pain, the source of the infection remains inside the tooth, meaning the problem is not solved.
Spread of Infection into the Jaw and Soft Tissue
If the infection is not drained and treated, it begins to spread rapidly into the surrounding anatomical structures of the head and neck. Bacteria can travel through the bone and soft tissues, leading to cellulitis, a severe, diffuse inflammation. This condition is marked by significant, painful swelling of the face, cheek, or neck that may quickly worsen over a period of days.
The infection may also spread into the jawbone itself, causing osteomyelitis, a severe and chronic bone infection that requires aggressive treatment. A more dangerous complication is the spread of infection into the deep fascial spaces of the neck and floor of the mouth. Infections in these areas, such as Ludwig’s angina, can cause swelling that compromises the airway, making it difficult to breathe or swallow. This is a life-threatening medical emergency requiring immediate hospitalization.
Systemic Health Risks from Untreated Infection
When localized defenses are overwhelmed, bacteria from the dental infection can enter the bloodstream, a condition known as bacteremia, posing serious risks to distant organ systems. The continuous presence of oral bacteria and resulting systemic inflammation can increase the risk of cardiovascular issues. Research suggests a link between chronic dental infections and the formation of arterial plaque, which may contribute to the risk of heart attack and stroke.
A severe complication is infective endocarditis, where bacteria infect the inner lining of the heart or its valves. An uncontrolled infection can lead to sepsis, a life-threatening response where the body’s reaction begins to damage its own tissues and organs. Bacteria can also track from the face to the brain, causing a brain abscess or cavernous sinus thrombosis, which involves a dangerous blood clot near the brain and requires immediate medical intervention.
Extraction and the Need for Tooth Replacement
The irreversible outcome of delaying or refusing a root canal is often the eventual loss of the tooth. A tooth becomes unsalvageable when the infection has caused excessive structural damage, such as extensive decay or fracture, or when the infection cannot be controlled by endodontic retreatment. Extraction removes the source of the persistent infection, but it leaves a gap that can lead to further oral health complications.
The missing tooth must be replaced to prevent adjacent teeth from shifting and to preserve the jawbone structure. Replacement options include a dental implant, which places an artificial root, or a fixed dental bridge, which requires modifying the neighboring teeth. These replacement options are more invasive and significantly more expensive than the initial root canal procedure intended to save the natural tooth.