A cracked tooth is a common dental problem involving a fracture line that does not always result in a visible chip or break. This fracture can be incredibly small, sometimes microscopic, making it difficult to detect without specialized tools. The crack may start on the chewing surface and extend downward, or it can begin in the root itself. What a person feels depends entirely on the location and depth of this fracture, which is why symptoms can be so varied and confusing.
Key Symptoms and Pain Characteristics
The sensation of a cracked tooth is typically not a constant, throbbing ache like a tooth abscess or severe decay. Instead, the pain is often intermittent, sharp, and fleeting, usually triggered by specific actions. The most telling symptom is a quick, sharp jolt of pain when chewing or biting down on food, especially when the object is small or hard. This discomfort occurs because the pressure causes the two fractured segments of the tooth to momentarily flex and shift.
The most distinctive characteristic of this pain often occurs not when biting down, but immediately upon the release of biting pressure, known as “rebound pain.” When the pressure is removed, the segments snap back together. This sudden movement irritates the dentin and the underlying pulp tissue, which contains the tooth’s nerves, causing a sudden, brief spike of agony. A cracked tooth also commonly causes heightened sensitivity to temperature changes, particularly cold, or may be triggered by consuming sweet foods.
How Crack Severity Affects Sensation
The depth and type of the fracture dramatically influence the kind of sensation a person feels. At the most superficial level are craze lines, which are extremely tiny, hairline cracks confined only to the outer enamel layer. These are often asymptomatic, causing no pain or sensitivity.
A slightly deeper issue is a fractured cusp, where a crack forms on one of the pointed chewing surfaces, often around an existing filling. The pain from a fractured cusp is typically sharp when biting directly on it. In contrast, a true cracked tooth extends from the chewing surface vertically toward the root, potentially reaching the dentin and the pulp. This type causes the classic intermittent pain and severe, prolonged sensitivity because the crack provides a direct pathway to the vulnerable nerve tissue.
A vertical root fracture is a distinct and often more problematic type, as the crack begins in the root and moves upward toward the crown. Since it is deep within the bone and gum, it may not cause the characteristic biting pain, but instead presents as a constant, dull ache. Symptoms may mimic periodontal disease, including swelling, inflammation of the nearby gum tissue, or the formation of a localized pocket on the gumline.
Immediate Action and Professional Assessment
If a person suspects they have a cracked tooth due to the onset of sharp, inconsistent pain, they should take immediate steps to protect the tooth from further damage. It is important to avoid chewing on the affected side of the mouth to prevent the crack from spreading or causing the tooth to break completely. Avoiding extreme hot or cold temperatures and hard or sticky foods can help minimize the painful thermal and pressure triggers.
A dental professional will use several techniques to confirm a diagnosis, since cracks are often invisible to the naked eye and may not appear on standard X-rays. They will perform a visual inspection and may apply a special staining dye to the tooth’s surface to make the fracture line more visible. A common diagnostic tool is a pointed plastic instrument, such as a “bite test” stick, which the patient bites on to reproduce the sharp pain, helping to pinpoint the exact location of the problematic tooth.
The dentist will also use transillumination, shining a strong fiber-optic light through the tooth, which highlights the fracture line as a shadow. Periodontal probing around the tooth is also performed to check for any isolated deep pockets that may suggest a vertical fracture extending below the gumline.