Tooth abrasion is a common form of non-carious tooth wear resulting from external mechanical forces rubbing against the tooth structure. This condition is distinct from dental erosion, caused by chemical acid dissolution, and attrition, which is wear from tooth-on-tooth contact. Abrasion gradually removes the protective outer layer of the tooth, the enamel, and can lead to significant dental health concerns. Understanding this mechanical damage is the first step toward effective prevention and management.
The Physical Mechanism of Tooth Abrasion
Abrasion involves the pathological loss of tooth substance caused by a foreign object repeatedly contacting the surface. The damage most frequently begins at the cementoenamel junction, the narrow area where the enamel meets the root surface near the gumline. Enamel is thinnest in this cervical region, and the underlying cementum is softer, making this area highly vulnerable to mechanical stress.
The continuous friction creates a characteristic V-shaped or wedge-shaped defect that deepens over time. Once the outer enamel layer is breached, the softer, yellowish dentin is exposed, accelerating the rate of wear. This exposure of the porous dentin, which contains microscopic tubules leading to the tooth’s nerve, causes the heightened sensitivity often associated with this damage.
Common Causes of Mechanical Wear
The primary cause of tooth abrasion stems from improper oral hygiene habits, specifically overly aggressive toothbrushing techniques. Using a hard-bristled toothbrush or applying excessive force, particularly with a horizontal scrubbing motion, physically scrapes away the tooth structure. This habit often concentrates mechanical stress right at the gumline, leading directly to the classic wedge-shaped lesions.
Another significant contributing factor is the regular use of highly abrasive toothpastes, often identified by high Relative Dentin Abrasivity (RDA) values. These pastes contain larger or harder abrasive particles designed to scour stains, intensifying the friction created by brushing. Combining an abrasive toothpaste with a vigorous technique creates a powerful, damaging mechanical force against the enamel and exposed root surface.
Non-brushing habits involving foreign objects can also cause localized abrasion. These activities include habitually chewing on items like pen caps or pencils, biting fingernails, or the friction created by improper flossing techniques or the clasps of removable partial dentures. Certain occupational habits, such as holding pins or nails between the teeth, can also cause specific, localized wear patterns.
Identifying the Visual Signs
The most recognizable sign of tooth abrasion is the appearance of distinct, shiny indentations on the tooth surface near the gum margin, known as the cervical area. These lesions typically present as V-shaped or wedge-shaped notches that have sharp, defined edges. Since the damage occurs outside the normal biting surface, these defects are usually found on the cheek-facing side of the teeth, particularly the canines and premolars.
When the outer enamel is worn away, the underlying dentin becomes exposed, making the affected area appear slightly yellow or darker than the rest of the tooth. Increased tooth sensitivity is also common, manifesting as a sharp, fleeting discomfort when consuming cold beverages, sweet foods, or inhaling cold air. In advanced cases, the mechanical trauma may also contribute to the recession of the gum tissue in the immediate area.
Treatment and Preventive Measures
Preventive measures focus on eliminating the sources of mechanical trauma to halt wear progression. The most effective change is adopting a proper brushing technique, which involves using a soft-bristled toothbrush and applying a gentle, circular, or vertical motion rather than horizontal scrubbing. Switching to a low-abrasive toothpaste, identified by a lower RDA score, significantly reduces frictional damage during daily cleaning.
Addressing habits like chewing on foreign objects or biting nails is also important to prevent further localized damage. For existing abrasion, professional dental management is necessary to protect the exposed tooth structure. Dentists often place composite resin fillings or glass ionomer cements directly into the V-shaped defects to cover the vulnerable dentin. These restorations seal the area and prevent the lesion from progressing deeper.
To manage associated discomfort, desensitizing agents or concentrated fluoride varnishes can be applied to the affected area to block the dentinal tubules. In severe cases involving significant loss of tooth structure, more comprehensive restorations like crowns or veneers may be necessary to restore the tooth’s function and integrity.