Abstract : The aims of this study are to highlight the risks associated with using topical drugs containing vasoconstrictors, especially in high-risk patients, and to find an alternative to adrenaline for local anesthesia in this experimental research. This randomized split-mouth controlled clinical study involved 80 patients undergoing orthodontic dental treatment, with 160 upper premolar extractions performed in a symmetrical manner. The average age of the patients was 19.75 years. Each patient's sample was divided into two symmetrical sides. The first side was anesthetized using lidocaine/adrenaline (the Control Group). The onset time of anesthesia, duration of action, pulse rate (PR), and peripheral blood oxygen saturation (SpO2) were recorded. The other side was anesthetized using lidocaine/dexmedetomidine (the experimental Group), and there was a five-day interval between the two interventions. Findings revealed no statistically significant difference in the onset time of anesthesia between the two groups (P=0.345). However, there was a statistically significant difference in the duration of anesthesia, with the adrenaline group showing a longer average duration compared to the dexmedetomidine group (P=0.001). There was no statistically significant difference in peripheral blood oxygen saturation (SpO2) in the two groups. Nevertheless, there was a statistically significant difference in pulse rate, with adrenaline causing an increase in pulse values (P=0.001), while dexmedetomidine caused a decrease in pulse (P=0.001). Dexmedetomidine may offer potential benefits in terms of improving the onset time of anesthesia, maintaining peripheral blood oxygen saturation (SpO2), and causing a reduction in pulse rate below normal levels compared to adrenaline as a local anesthetic alternative.