A cracked tooth is a common injury where a fracture occurs in the hard structure of a tooth. This damage can range from a tiny, superficial line to a deep split that extends into the root. This injury often brings sharp pain or significant sensitivity. Unlike a broken bone or a cut on the skin, a cracked tooth cannot mend itself through natural biological processes. Understanding the tooth’s composition and the fracture’s severity is the first step toward seeking appropriate care.
Why Teeth Cannot Heal Themselves
The inability of a cracked tooth to heal itself is tied to the non-cellular structure of its outer layers. Teeth are not bones, which have a rich blood supply and active living cells that continuously remodel and repair tissue. The outermost layer, the enamel, is the hardest substance in the human body, composed almost entirely of mineral crystals. Once fully formed, this layer is avascular (lacks blood vessels) and lacks the living cells necessary for regeneration.
Beneath the enamel lies the dentin, a more porous tissue that makes up the bulk of the tooth structure. Dentin contains microscopic tubules and is formed by specialized cells called odontoblasts, located in the innermost pulp. While the pulp, which holds the nerves and blood vessels, can produce secondary dentin in response to irritation, this mechanism is limited. It cannot repair a structural fracture that passes through the external mineralized tissue, creating an irreversible defect that allows bacteria to penetrate.
Identifying the Severity of a Tooth Crack
The prognosis for a cracked tooth depends entirely on the depth and orientation of the fracture line. Craze lines are the most minor type, appearing as superficial hairline fractures that affect only the enamel. These lines are common, cause no pain, and rarely require treatment beyond cosmetic consideration.
A fractured cusp occurs when a piece of the chewing surface breaks off, often near an existing filling, and usually does not extend into the pulp chamber. A true cracked tooth extends vertically from the chewing surface toward the root, potentially involving the inner pulp tissue. This type often causes pain when biting down or when exposed to temperature changes, indicating the crack is flexing and irritating the internal nerve.
The most severe types are the split tooth and the vertical root fracture. A split tooth has separated the tooth into two distinct segments. A vertical root fracture begins below the gum line at the root and moves upward. These severe fractures are challenging to manage and often lead to tooth loss.
Required Dental Treatments and Urgency
Since teeth cannot heal themselves, professional intervention is necessary to prevent the crack from worsening and to seal internal structures from infection. Minor cracks, such as craze lines or small chips, can often be addressed with dental bonding, where a tooth-colored composite resin is applied to restore the tooth’s form. For a fractured cusp or a moderate crack confined to the crown, a dental crown, or cap, is typically used to cover the tooth and provide structural support, preventing the crack from spreading during chewing.
If the crack extends into the pulp, exposing the delicate nerve tissue to bacteria, a root canal procedure becomes necessary. This treatment removes the infected pulp tissue, disinfects the internal chamber, and seals the tooth to prevent further contamination.
Delaying treatment for a deep crack increases the risk of the crack reaching the root, which can lead to infection, abscess formation, and eventual tooth extraction. Immediate professional assessment is paramount, as the primary danger of an untreated crack is the subsequent infection that compromises the entire tooth structure.