A “universal” adhesive is not a technical term but rather a clinical term. It implies that an adhesive can be used with or without phosphoric acid on dentin or enamel. In scientific writing, these adhesives are sometimes referred to as mild self-etch adhesives because they have a slightly less acidic pH (around 3) than typical self-etch materials (around 2). Another implication of a “universal” is the addition of monomers that allow bonding to indirect restorations, namely the monomers silane (for glass-based ceramics) or 10-MDP (for zirconia and some metals). Universal adhesives are typically single-bottle systems.