Thirty volunteers received maxillary buccal injections of 4% articaine HCl with 1:100,000 epinephrine or 1:200,000 epinephrine bilaterally to the first premolar or first molar. Magnetic resonance images were obtained before and 5 minutes after local anesthetic injections, and a visual evaluation was done to determine the presence of local anesthetic solution at palatal tissues. Anesthesia of palatal tissues after buccal injection was assessed by needle-prick stimulation pain with a visual analog scale (VAS)