What is the solvent in 6th- and 7th-generation bonding agents?

6^th– and 7^th-generation bonding agents have water as a solvent. Removal of the solvent is typically done by gentle air-drying, although one product (G-BOND, GC America) requires vigorous air-drying. One 7^th-generation bonding agent (Bond-1 SF Solvent Free SE Bonding Agent, Pentron Clinical Technologies) is solvent-free and does not require air-drying.