Which area of the root is most commonly affected by root hypersensitivity?

Root hypersensitivity most commonly affects the cervical area of the root. This is largely due to the anatomical features and the prevalence of exposed dentin that occurs in this region. The cervical area is where the enamel transitions into cementum, and it is often more susceptible to recession and abrasion from both mechanical factors, such as tooth brushing, and pathological factors, such as periodontal disease.

When the gums recede or when there is loss of supporting tissue around the teeth, the dentin in this area can become exposed, facilitating sensitivity. Exposed dentin has tubular structures that can transmit stimuli such as thermal, chemical, or tactile sensations to the nerve endings, which is the primary reason for the sensation of pain associated with root hypersensitivity.

In contrast, the apical area is typically covered by bone and periodontal tissue, providing it a level of protection. The middle third may not experience as much exposure or susceptibility to the factors that cause hypersensitivity compared to the cervical area. Although the coronal area generally refers to the part of the tooth that is above the gum line and is covered by enamel, it is not typically associated with hypersensitivity in the context of root surfaces.