A cracked tooth is a structural break in the hard tissue that protects the tooth’s inner layers, ranging from a microscopic line to a complete split. This damage creates a pathway for oral bacteria to invade the sensitive internal structures. Because the protective enamel and dentin layers are breached, a cracked tooth requires prompt professional evaluation. Delaying treatment only increases the risk of the crack deepening, leading to irreversible damage to the pulp tissue and surrounding bone. Assessment by a dental professional is necessary to determine the crack’s extent and prevent further complications.
Severity Determines the Timeline
The length of time a cracked tooth can go untreated varies significantly based on the severity and direction of the fracture line. Superficial flaws known as craze lines affect only the outermost enamel layer and often require no treatment beyond monitoring, potentially remaining stable for years. These minor defects rarely present an immediate threat to the tooth’s health.
A fractured cusp is a different category, where a piece of the chewing surface breaks off, generally extending into the underlying dentin layer. This condition exposes the dentin to bacteria and chewing forces, meaning treatment with a crown or filling should occur within days to a couple of weeks to prevent further fracture. A true cracked tooth is a vertical fracture originating on the chewing surface that progresses toward the root. If this fracture reaches the pulp tissue, the time window before irreversible infection begins can be as short as hours to a few days.
The most severe types are the split tooth and the vertical root fracture, both considered immediate dental emergencies. A split tooth is the result of a cracked tooth that has progressed to separate into two distinct segments. The vertical root fracture starts in the root and moves upward, often causing severe damage that quickly leads to infection and bone loss. For these fractures, treatment must be sought within hours, as the prognosis worsens with every day of delay, often resulting in extraction.
The Progression of Internal Damage
Allowing a crack to remain untreated initiates a destructive biological cascade. The breach in the enamel and dentin creates a direct route for pathogenic bacteria to migrate toward the inner pulp chamber. Once bacteria reach the pulp, which houses the nerve and blood vessels, they cause inflammation known as pulpitis.
If the crack is shallow, the inflammation may be reversible, but as the bacteria multiply and the crack deepens, the pulpitis quickly becomes irreversible. This progressive inflammation leads to the death (necrosis) of the pulp tissue, which can no longer fight the infection. The infection then travels past the root tip, spreading into the surrounding jawbone to form a periapical abscess—a painful pocket of pus.
An untreated abscess can cause localized bone loss and swelling in the gums, but the risks can spread far beyond the mouth. The infection can disseminate into the soft tissues of the face and neck (cellulitis). If the infection enters the bloodstream, it can lead to sepsis, a life-threatening, system-wide inflammatory response. Leaving the tooth untreated turns a localized dental issue into a potential threat to general health.
Treatment Options Based on Crack Depth
The necessary treatment for a cracked tooth is determined by how deep the fracture has penetrated the tooth structure. For minor cracks confined to the outer enamel or small fractures in the dentin, a dentist may use dental bonding or a simple filling. Bonding involves applying a tooth-colored resin to seal the crack and stabilize the tooth.
If the crack extends deeper into the dentin, affecting structural integrity but not yet reaching the pulp, the standard intervention is often a dental crown. A crown is a custom-made cap that covers the entire chewing surface, binding the fractured segments together to prevent further crack propagation. Early placement of a crown can significantly improve the long-term prognosis.
When the crack has reached the pulp tissue, causing irreversible inflammation or infection, treatment escalates to root canal therapy. This procedure removes the infected pulp tissue, sterilizes the area, and seals it, followed by crown placement to protect the now-brittle tooth. Delaying care often forces the progression from a simple filling to a root canal, or ultimately, to extraction. If the crack extends below the gum line or splits the tooth entirely, the damage is typically non-restorable, and the tooth must be removed.