Pulp response to cold and electrical sensibility tests in patients with hypothyroidism: an analytical cross-sectional study

Abstract

Thyroid disorders are the second most common endocrine diseases worldwide. Hypothyroidism has been associated with peripheral neuropathy; however, its potential effects on dental pulp sensibility remain poorly understood. This study aimed to compare responses to cold and electric pulp tests (EPT) between patients with hypothyroidism and healthy individuals. This analytical cross-sectional study was conducted at the Endocrinology Clinic of Shahid Sadoughi Hospital, Yazd, Iran. A total of 292 participants aged 18–58 years were enrolled, including 146 patients with primary hypothyroidism and 146 age-matched healthy participants. The study population was predominantly female (144 females and 2 males in the hypothyroid group; 138 females and 8 males in the healthy group). Primary hypothyroidism was confirmed by an endocrinologist based on elevated serum thyroid-stimulating hormone (TSH) and reduced free thyroxine (T4) levels. One maxillary central incisor from each participant was evaluated using the cold test and EPT. The EPT threshold and response latency to the cold test were recorded. Data were analyzed using the independent t-test, with statistical significance set at P < 0.05. The mean EPT threshold was significantly lower in the hypothyroid group than in the healthy group (2.22 ± SD vs. 2.42 ± SD, P = 0.015; scale: 0–10). Likewise, the mean response latency to the cold test was significantly shorter in patients with hypothyroidism than in healthy participants (2.14 ± SD vs. 2.37 ± SD seconds, P = 0.023). Patients with hypothyroidism exhibited significantly lower electrical stimulation thresholds and shorter response latencies to cold stimuli than healthy individuals. These findings suggest altered dental pulp neural sensitivity in patients with hypothyroidism and support the potential influence of thyroid dysfunction on pulpal sensory responses.