When you hear the term ‘root canal infection,’ it might sound scary to you. However, learning more about what it is and the various causes can help you feel confident in making the best decisions to protect your smile and maintain strong oral health. At its most basic level, root canal infection is the result of bacteria infiltrating the tooth’s pulp. That’s the soft tissue located in the centre of the tooth, where nerves and blood vessels reside. Normally, the hard enamel and dentin protect this area. However, once the protective outer layer is breached, bacteria can invade the pulp, multiply, and cause an infection.
How Does Tooth Decay Lead to Infection?
One of the most common ways a root canal infection develops is through deep tooth decay. Cavities start on the outer enamel and, if left untreated, can continue to eat through the tooth’s layers until they reach the pulp chamber. Once bacteria get in there, they have direct access to the sensitive inner tissues — and because that space has no natural blood supply once infected, your immune system can’t easily clear them out.
Can Cracks or Chips in Teeth Cause an Infection?
Yes — even a small crack or chip in a tooth can be an entryway for bacteria. The break in the enamel is like an open invitation for microbes to travel deep within the tooth and into the pulp. This could occur from an accident, biting down on something hard, or even from long-term habits such as grinding the teeth. It doesn’t take long for inflammation and infection to begin once bacteria enter the pulp.
Does Dental Work Itself Ever Cause Infection?
It might seem unlikely, but past dental work can also be a factor—particularly if a filling or crown is old, leaking, or has developed gaps with age. Tiny spaces between old restorations and the natural tooth allow bacteria to creep under the seal and get into places they shouldn’t. Repeated work on the same tooth or incomplete cleaning during prior treatment can also make the tooth more vulnerable to infection.
Can Gum Disease Lead to a Root Canal Infection Too?
Yes. Advanced gum disease (periodontitis) is an infection of the gums and other structures that support the teeth. It can spread underneath the gums and down around the roots of the teeth. Bacteria can travel along these channels into the deeper layers of the tooth. If the pulp becomes infected, the pulp chamber can be affected.
Is Trauma or Injury a Risk?
Big impacts and subtle damage alike can set the stage for infection. A blow to the mouth that cracks a tooth might be obvious, but even trauma that doesn’t visibly fracture the tooth can injure the pulp internally. Blood supply disruption inside the tooth weakens its defences, making it easier for bacteria to cause an infection.
Are There Everyday Factors That Increase the Risk?
Yes — and they’re often things we don’t think about until it’s too late. Poor oral hygiene, a sugary diet, or missing regular dental check‑ups all allow plaque and bacteria to build up around your teeth. Over time, this increases your chances of deep decay or gum problems — both of which can open the door to a root canal infection.