An abfraction lesion is a non-carious cervical lesion characterized by a wedge- or V-shaped notch at the cementoenamel junction (CEJ), resulting from stress concentration caused by occlusal loading forces rather than bacterial decay. Unlike cavities, these defects arise through biomechanical fatigue that disrupts the crystalline structure of enamel and dentin over time.

How Abfraction Lesions Form

The prevailing theory holds that eccentric or parafunctional occlusal forces — particularly those associated with bruxism or malocclusion — generate flexural stress that concentrates at the cervical fulcrum of the tooth. This stress causes microfractures in the relatively brittle enamel rods near the CEJ, progressively breaking down tooth structure. Once enamel is lost, the underlying dentin becomes vulnerable to further mechanical wear and chemical erosion, accelerating lesion depth.

Common Contributing Factors

• Bruxism and clenching — parafunctional habits that amplify lateral and compressive occlusal forces
• Malocclusion — improper occlusal contacts that redirect stress toward the cervical region
• Aggressive toothbrushing — a frequent co-factor that removes already-weakened enamel
• Dietary acid erosion — softens enamel, increasing susceptibility to stress-induced fracture
• Steep cuspal inclines — concentrate lateral forces during excursive jaw movements

Clinical Significance

Abfraction lesions most frequently appear on premolars and canines, the teeth that experience the greatest lateral loading during excursive jaw movements. Clinically, they present as sharp-margined, wedge-shaped defects that feel hard and sclerotic on tactile examination, distinguishing them from the softer texture of carious lesions. As dentin becomes exposed, dentin hypersensitivity is a hallmark complaint, with patients reporting sharp, transient pain triggered by thermal, tactile, or osmotic stimuli.

Left unmanaged, these lesions can progress toward the pulp, risking pulpal involvement and compromising the long-term prognosis of the tooth. The periodontal ligament and surrounding bone may also be affected when lesions extend subgingivally.

Diagnosis and Management

Accurate diagnosis requires differentiating abfraction from abrasion and erosion, conditions that frequently coexist at the cervical region and can obscure the primary etiology. Treatment is multifactorial: reducing the causative occlusal force is the priority, often through occlusal equilibration or a protective nightguard for patients with bruxism. Composite resin restorations can rebuild lost tooth structure and reduce dentin hypersensitivity, but they are prone to debonding if the underlying biomechanical imbalance remains unaddressed.

Identifying and correcting the occlusal etiology is the most critical step — restoring the lesion alone without managing the force imbalance reliably leads to recurrence.