This study evaluated the acute pulpal healing response following preparation, etching, and sealing of the prepared vi tal dentin with a 4-methacryloxyethyl trimellitate anhydride (4-META) bonding system. Adult monkey teeth received crown preparations with chamfer margins, prepared with a diamond used at ultra high speed with water cooling. Vital dentin was etched with 10% citric acid-3% ferric chloride, rinsed, and sealed with the 4-META system. A provisional crown was formed with a low-viscosity light-curing adhesive resin. Teeth were fixed and evaluated histopathologically. Pulpal responses at 3 days showed only minimal disruption of the odontoblastic zone. At 7 days, the pulps presented reorganizing odontoblastoid cells, and, at 10 days, the pulps shoed new odontoblastoid cells with a thin rim of reparative dentin. Pulps of crown preparations that were etched and then sealed with the 4-META system presented healing patterns similar to those of pulps associated with Class V preparations lined with calcium hydroxide, observed in (previous) similar studies.