Sensory processing sensitivity (SPS) is a biologically determined trait that influences how individuals respond to external and internal stimuli. A high level of SPS is characterized by three factors: increased emotional reactivity, heightened sensitivity to subtle stimuli, and greater susceptibility to overstimulation, all of which may impact well-being and health. This study examined the relationships between SPS, perceived stress, affect, and biochemical responses in adult dental patients (N = 157) on the day of a routine dental visit. Biochemical measures included morning cortisol and serotonin secretion (saliva samples), and cortisol concentration accumulated in recent months (hair sample). Perceived stress and negative and positive affect were assessed while patients waited for a dental procedure. The correlation analysis revealed that higher SPS level was associated with elevated hair cortisol and more negative affect. Cluster analyses tested SPS and its factors independently, revealing that individuals with higher SPS had higher cortisol levels in saliva and hair samples, as well as greater perceived stress and negative affect. Salivary serotonin levels showed varied relationships with different SPS factors, indicating the need to analyze SPS as a multidimensional construct. The results indicate that increased hair and salivary cortisol may be considered as biomarkers of SPS. In the context of patient-centered care, considering SPS levels may contribute to enhanced motivation for regular dental visits and improved treatment adherence.