Etching compositions, curable compositions, packaged products and methods of use for the treatment of bone substrate, i.e., teeth, are described. The etch compositions generally include a gelling agent, an inorganic acid, an organic acid and either a solvent, a surfactant or mixtures thereof. The curable composites include reactive monomers and crosslinking agents that are effective to adhere to the surface of the treated substrate. The methods of the invention provide the ability to modify a bone or bone-like surface so that the curable composition, such as an adhesive resin, can be used in combination with a restorative material.