Which local anesthetic has the longest duration of action?

Bupivacaine (Marcaine) is the longest-acting local anesthetic used in dentistry — pulpal anesthesia ~60 min, soft tissue ~5–12 hours. It's used for procedures requiring prolonged anesthesia or postoperative pain control. Lidocaine and mepivacaine are intermediate. Articaine has faster onset but shorter duration than bupivacaine.