Physiological and Subjective Measures Associated with Withdrawal from Intravenous Sedation in Dental Phobia: A Prospective Cohort Study

<b>Background:</b> Patients with dental phobia frequently require intravenous sedation (IVS) to undergo dental treatment; however, some can gradually discontinue IVS through repeated clinical experiences. The physiological and psychological factors influencing successful IVS withdrawal remain unclear. This study aimed to compare physiological (sAA, HR) and subjective (VAS) measures between patients who discontinued IVS and those who remained dependent on IVS. <b>Methods:</b> This prospective cohort study included 51 patients with dental phobia treated under IVS. Participants were classified into a Non-Sedation Group (NSG; <i>n</i> = 25) and a Sedation-Dependent Group (SDG; <i>n</i> = 26) based on their ability to discontinue IVS during the course of treatment. Salivary alpha-amylase (sAA), heart rate (HR), and visual analog scale (VAS) scores for fear, tension, and anxiety were assessed at predefined time points from the waiting room to venous cannulation. Treatment satisfaction and expectations for future treatment were also evaluated. <b>Results:</b> sAA activity was significantly higher in the SDG than in the NSG at T0 and T1 (<i>p</i> < 0.05), indicating higher levels of selected physiological measures during anticipatory phases; however, the difference at T2 was not significant. HR differed significantly only in the waiting room, whereas no between-group differences were observed in self-reported VAS scores for fear, tension, or anxiety at any time point, indicating a dissociation between physiological and subjective stress measures. Treatment satisfaction and expectations for future treatment were significantly higher in the SDG. <b>Conclusions:</b> Patients who remained dependent on IVS showed higher levels in selected physiological measures at the group level during anticipatory stages, whereas no corresponding differences were observed in self-reported subjective measures. These findings are exploratory and descriptive in nature and do not imply predictive or causal relationships.