Prime Etching Liquid is based on 37% phosphoric acid indicated for composite restorations, indirect restoration like composite or metal free ceramics along with recommended adhesive cement and bonding orthodontic brackets.
It is stable formulation that does not dry or thicken over storage. Also the etchants are developed silica free since left over silica particles are known to be detrimental for bonding. Direct exposure to pulp tissue should be avoided.