What cement should generally not be used with acrylic temporaries that will be placed a long time?

Zinc phosphate cement is generally not recommended for use with acrylic temporaries that will be in place for an extended period. This is due to its potential to cause irritation and sensitivity in the pulp of the tooth, as well as its inability to bond adequately to acrylic materials. Instead, a more appropriate choice would be a resin-modified glass ionomer cement, which provides better adhesion and is less likely to irritate the surrounding tissues.