The root canal procedure is a dental treatment designed to save a tooth when its interior, known as the dental pulp, becomes infected or inflamed. The dental pulp is a soft tissue within the tooth’s core, housing nerves, blood vessels, and connective tissue. When deep decay, a crack, or an injury allows bacteria to enter this inner chamber, an infection takes hold. An untreated root canal means that this bacterial colony is left to multiply and spread within the tooth’s canal system.
The Onset of Acute Symptoms
The initial stage of an untreated infection is often marked by a rapid escalation in discomfort, signaling acute pulpitis. Inflammation and pressure inside the pulp chamber increase dramatically, leading to a persistent, throbbing ache difficult to manage with over-the-counter medication. The tooth frequently becomes highly sensitive to heat or pressure from chewing.
As the bacterial infection progresses, the pressure seeks an exit, typically moving down the root tip and forming a periapical abscess. This abscess is a localized collection of pus—a mixture of dead white blood cells, tissue debris, and bacteria—at the end of the root. In some cases, the acute, severe pain may suddenly diminish or disappear entirely when the dental pulp tissue dies, a process called necrosis. This cessation of pain is a deceptive sign, however, as the infection remains active, having simply killed the nerve responsible for the initial sensation.
Localized Progression and Bone Damage
Once the acute phase has passed, the infection often transitions into a chronic state, where bacteria steadily destroy the structures surrounding the tooth root. The pus from the chronic infection begins to dissolve the jawbone tissue surrounding the root tip, a process termed bone resorption or lysis. This continuous destruction results in a permanent lesion in the jawbone, visible on X-rays as a dark area surrounding the root end.
To relieve the chronic pressure from accumulating pus, the body may create a channel through the jawbone and gum tissue. This opening is known as a sinus tract or fistula, which appears as a small, recurring pimple or boil on the gum line near the affected tooth. The tract allows the pus to drain into the mouth, often alleviating swelling and internal pressure. This means the patient may not feel pain despite the ongoing, destructive infection, but the chronic drainage signifies that the infection is actively causing structural damage to the supporting bone.
Systemic Health Complications
Allowing the bacterial infection to persist significantly elevates the risk of causing serious systemic health complications beyond the jaw. The infection can spread directly from the root tip into the soft tissues of the face and neck, resulting in a rapidly expanding and dangerous condition called cellulitis. A particularly severe and potentially life-threatening form is Ludwig’s Angina, where the infection causes massive swelling on the floor of the mouth that can rapidly compromise the patient’s airway.
The bacteria can also breach local defenses and enter the bloodstream (bacteremia), which can lead to a widespread body infection called sepsis. The immune system becomes overwhelmed, and the infection can travel to distant organs. Although rare, a severe infection can travel to the brain, causing a brain abscess, or affect the venous sinuses around the brain, leading to cavernous sinus thrombosis.
A chronic, uncontrolled dental infection also poses a significant risk to individuals with pre-existing medical conditions. Those with compromised immune systems, such as people undergoing chemotherapy or with autoimmune disorders, are less able to contain the infection, leading to faster spread. An ongoing dental infection can also complicate the management of diabetes and has been linked to negative outcomes in individuals with heart conditions.
Extraction as the Final Outcome
If the infection is ignored for too long, localized bone destruction and structural damage can progress until the tooth cannot be saved. When supporting structures are too compromised, or the tooth is too weakened, extraction becomes the only viable treatment option to eliminate the source of the infection. This outcome guarantees the loss of the natural tooth, requiring subsequent restorative dentistry.
Replacing a lost tooth necessitates significantly more complex and costly procedures than the original root canal. The patient must consider options such as a dental implant, a fixed bridge, or a partial denture to restore function and aesthetics. These subsequent treatments involve additional surgical procedures, multiple appointments, and a greater overall expense compared to timely root canal therapy.