What kind of glue do cosmetic dentists use for gluing porcelain veneers?

Resin cement: These days i would say resin cements are the only "glue" used for cementing veneers into place. They are strong, they do not dissolve in saliva, they are color stable, and they also bond well to porcelain.

Resin cement: Porcelain veneers, unlike some dental restorations that are "glued in" must be bonded to the tooth, preferably the enamel layer. There are a number of dental cements on the market--porcelain veneers are bonded with resin cements. The veneer and the tooth are both prepared with special gels and chemicals and them the veneer is bonded to the tooth. Careful technique is important!

Resin: Since porcelain veneers don't have any friction (compared to crowns or fillings, which grip the tooth in large areas), they need to be permanently "bonded" to the underlying tooth structure. The quality of the bond is critical to long-term success. The best "glue" is a "resin" cement, sometimes also called a "composite" cement. These agents are very strong and predictable and have decades of use.