Understanding Abfractions
Abfraction refers to the pathological loss of tooth structure that occurs at the gumline, often presenting as a wedge-shaped or V-shaped notch. This damage is typically found on the cheek side of teeth, particularly at the cementoenamel junction (CEJ), where the crown meets the root. Unlike cavities caused by bacteria, abfractions are a mechanical loss of tooth material resulting from biomechanical loading forces.
Individuals with abfractions may experience various symptoms, including sensitivity to hot or cold temperatures, or discomfort when brushing the affected area. The exposed dentin, which is less dense than enamel, contributes to this sensitivity. The notches can also be a cosmetic concern and may trap food debris.
It is important to distinguish abfractions from other forms of tooth wear, such as abrasion and erosion. Abrasion is mechanical wear caused by external friction, like aggressive brushing with a hard-bristled toothbrush, and often appears as a flat, worn area. Erosion, conversely, involves the chemical dissolution of tooth structure due to acids from diet or conditions like acid reflux. While abfractions are primarily caused by internal forces, they can sometimes occur alongside or be worsened by abrasion and erosion.
Why Abfractions Occur
Abfractions primarily develop due to excessive or misdirected occlusal (biting) forces on the teeth. This includes habits like clenching or grinding teeth, known as bruxism, and malocclusion, which is the misalignment of teeth. These forces create stress concentrations at the weakest point of the tooth, which is the cervical area near the gumline.
The biomechanical process involves the tooth flexing under these biting stresses. As the tooth bends, particularly at its neck, the enamel and dentin undergo fatigue and microfractures. Over time, this repetitive stress causes microscopic pieces of the tooth structure to chip away, leading to the characteristic defect. This mechanism is often described as the “flexure theory,” where tensile and compressive stresses break down the tooth material.
While occlusal stress is considered the primary driver, other factors can contribute to the development or progression of abfractions. Aggressive tooth brushing, especially with a hard-bristled brush, can exacerbate the issue by physically removing weakened tooth structure. Similarly, an acidic diet or conditions causing acid exposure can soften the tooth surface, making it more susceptible to chipping from mechanical forces.
Managing and Preventing Abfractions
Addressing existing abfractions often involves restorative treatments to protect the tooth and alleviate symptoms. A common approach is filling the lesion with a tooth-colored composite resin, which reduces sensitivity and improves the tooth’s appearance. For more extensive damage, or if gum recession is also present, a gum graft might be considered to cover the exposed root surface.
Beyond treating the visible lesion, managing abfractions requires addressing the underlying causes to prevent recurrence or further damage. For individuals who clench or grind their teeth, a custom-fitted nightguard can protect teeth from excessive forces during sleep. Orthodontic treatment may be recommended to correct tooth misalignment (malocclusion) and ensure biting forces are distributed evenly across the teeth.
Prevention strategies focus on reducing the biomechanical stresses that lead to abfractions. Regular dental check-ups are important for early detection and intervention. Awareness of clenching or grinding habits during the day can help individuals modify these behaviors, potentially through stress-reduction techniques. Adopting proper oral hygiene practices, such as using a soft-bristled toothbrush and a gentle brushing technique, helps prevent further tooth wear.