Exposed tooth roots occur when the protective gum tissue surrounding the teeth pulls away, a condition formally known as gingival recession. The exposed root surface is covered by cementum and dentin, which are softer than the enamel protecting the crown of the tooth. This lack of hard covering leaves the tooth vulnerable to wear and decay. Symptoms of this exposure include heightened sensitivity to hot, cold, or sweet stimuli, a visible lengthening of the tooth, and a notched feeling near the gum line.
Periodontal Disease
The most widespread pathological cause of exposed tooth roots is periodontal disease, a chronic infectious process. This condition begins with the accumulation of bacterial plaque along the gumline, leading to gingivitis, which is characterized by gum inflammation and bleeding. If the bacterial biofilm is not removed, the process advances to periodontitis, an irreversible, destructive disease. The body’s immune response to the persistent bacterial infection inadvertently begins to break down the supporting structures of the tooth, including the periodontal ligament and the alveolar bone.
This chronic inflammation causes the soft tissue to detach from the tooth surface, creating deep spaces called periodontal pockets that harbor more bacteria. As the infection progresses, the destruction of the underlying alveolar bone forces the gum tissue to migrate down the root surface, leading to recession. This process is driven by internal infection and inflammation, often resulting in widespread tissue loss around multiple teeth. Unlike trauma-related recession, this immune-mediated bone destruction is a slow, steady process that ultimately exposes the root surface.
Aggressive Brushing and Improper Technique
Another common cause of root exposure is mechanical trauma resulting from improper oral hygiene habits. Using a hard-bristled toothbrush, applying excessive force, or employing a vigorous horizontal scrubbing motion can physically wear away the delicate gum tissue over time. This force is often significant, with studies indicating that brushing forces exceeding 3.8 Newtons (N) can lead to severe recession, compared to forces below 2.1 N in areas without tissue loss. The repeated back-and-forth action causes a form of erosion known as cervical abrasion, which appears as a notch near the gum line.
This trauma-induced recession is frequently localized, typically affecting the teeth most accessible to the dominant hand’s scrubbing action. The canine and premolar teeth are often the first to show signs of this mechanical wear due to their prominent position in the dental arch. Unlike recession from infection, the gum tissue in these areas often appears healthy, firm, and pink, though it has been physically stripped away. Recognizing this pattern is important because correcting the technique—switching to a soft-bristled brush and using a gentle, circular motion—can stop the recession from progressing.
Anatomical Structure and Tooth Alignment
A person’s inherent structural anatomy can increase their predisposition to gum recession, even without infection or trauma. The thickness of the gum tissue, known as the gingival biotype, is a major genetic factor. Individuals with a thin biotype (less than 1.5 millimeters thick) possess delicate gums that are less resistant to mechanical stress or inflammation. This thin tissue is more likely to recede when challenged by minor forces.
Furthermore, the position of a tooth within the jawbone can create a susceptibility to root exposure. If a tooth is naturally tilted or rotated, its root may be positioned too far toward the outer surface of the jaw, resulting in a thin layer of overlying bone or a complete lack of bone cover, known as a dehiscence. This lack of a bony plate means the overlying gum tissue has little structural support, making it highly prone to recession. Another anatomical factor is a shallow oral vestibule, where muscle attachments can exert traction on the gum margin, pulling it away from the tooth.
Habitual Forces and Lifestyle Contributors
Chronic, non-functional forces and lifestyle choices introduce additional stresses that accelerate gum tissue loss. Parafunctional habits such as bruxism, which is the unconscious clenching or grinding of teeth, subject the supporting structures to excessive, sustained pressure. This chronic biting force strains the periodontal ligament and can trigger the reabsorption of the alveolar bone, which in turn causes the overlying gum tissue to recede. This effect is particularly damaging when combined with existing gum inflammation.
Tobacco use, whether smoking or chewing, is a significant chemical contributor to root exposure. Nicotine acts as a potent vasoconstrictor, severely reducing blood flow to the gum tissues. This impaired circulation restricts the delivery of oxygen, nutrients, and immune cells necessary to fight infection and repair damaged tissue. Smokers also tend to have higher plaque accumulation and a compromised immune response, increasing the rate of bone and tissue loss. Other localized irritants, such as oral piercings, can cause recession by constantly rubbing and physically traumatizing the gum margin on a specific tooth.