The aim of this study was to determine changes in arterial pressure (AP) and heart rate (HR) during dental treatment under local infiltration anesthesia (LIA) in patients with controlled arterial hypertension (AHT) versus normotensive patients. A longitudinal comparative study involving repeated measurements in well-controlled hypertensive (cases) and normotensive patients (controls) was conducted. All patients received standardized preventive periodontal treatment under LIA (1.8 ml of 4% articaine with 1:100000 L-Adrenaline). AP and HR were determined at 5 different phases of treatment. The study comprised 82 patients, 46.3% of whom were hypertensive, 61% were female. Systolic (SAP) and diastolic (DAP) arterial pressure and HR increased as the procedure advanced and then returned to initial values in both groups. Average HR values were lower in normotensive than in hypertensive patients (p < 0.001). Significant differences in AP and HR were observed among initial, mid-procedure, and final values (p < 0.001). Both groups exhibited highest SAP values post-LIA administration (p < 0.01). Average HR was higher in normotensive than in hypertensive patients. The hypertensive patients tended to develop AHT (> 140/90 mmHg) more frequently throughout the procedure (p = 0.002), SHOWING a 4.93-fold higher risk. Logistic regression analysis showed that sex (p < 0.032) and AH (p < 0.007) were associated with a tendency to develop AHT during treatment. Controlled hypertensive patients with normal AP values at the onset of dental treatment were found to be at a 5-fold higher risk of developing AHT during the course of dental treatment under local infiltration anesthesia. The observed increases in AP, however, did not reach clinically significant levels. The HR values tended to increase with the progress of dental treatment in all patients. HR was lower in hypertensive patients probably due a drug effect.