Cracked Tooth Syndrome (CTS) is a condition in which an incomplete fracture through the enamel and dentin of a posterior tooth produces sharp, fleeting pain — most often triggered by biting or releasing pressure — that is notoriously difficult to diagnose due to its intermittent and elusive nature.
Unlike a visible broken cusp or a complete split, the crack in CTS has not yet propagated through the entire tooth structure. The tooth may appear radiographically normal during routine examination, yet still cause substantial discomfort — a combination that frequently leads to delayed or missed diagnoses.
Why It Matters
Left untreated, a crack can extend apically toward the root, involve the pulp, or track alongside the periodontal ligament — each scenario representing a progressively worse prognosis. Timely identification can mean the difference between a cuspal-coverage restoration and extraction.
Common Causes and Risk Factors
Several factors increase susceptibility to CTS:
- Parafunctional habits — bruxism and clenching subject teeth to repetitive, high-magnitude occlusal forces
- Large existing restorations — extensive amalgam or composite fillings can wedge remaining tooth structure under load
- Steep cuspal anatomy — pronounced cusp inclines redirect lateral forces that stress enamel and dentin
- Trauma — a single blow or biting on a hard, unexpected object can initiate or propagate a crack
- Thermal cycling — repeated contraction and expansion from hot and cold foods fatigues already-compromised tooth structure
Diagnosis and Treatment
The hallmark symptom is a sharp pain on biting that resolves immediately when pressure is released. A bite test using a tooth sleuth or wooden stick — applied to individual cusps — helps localize the fracture. Transillumination and methylene blue dye can reveal crack lines invisible to the naked eye. When the pulp is involved, lingering cold sensitivity may indicate irreversible pulpitis, necessitating endodontic treatment before any definitive restoration.
Treatment ranges from occlusal adjustment and bonded restorations for superficial cracks to full-coverage crowns that bind cusps and resist further propagation. Cracks extending into the root or through the pulp floor carry a guarded to poor prognosis and may ultimately require extraction.
Prompt diagnosis paired with a cuspal-coverage restoration — and an occlusal splint in bruxing patients — offers the best chance of preserving the tooth and preventing irreversible structural compromise.