Which concentration of phosphoric acid is used for total acid etch technique with composite?

The total acid etch technique, commonly used in restorative dentistry, typically employs phosphoric acid concentrations in the range of 30-40%. This concentration is effective for creating micro-retentive surfaces on enamel and dentin, promoting better mechanical bonding for composite materials. The etching process alters the surface topography, allowing the composite to adhere more securely, which is essential for the longevity and success of the dental restoration.

When phosphoric acid etches enamel, it removes the smear layer and demineralizes the outer layer of the tooth structure, enhancing micromechanical retention. Using a concentration within this range ensures that the etching is sufficiently aggressive to achieve the desired bonding conditions without risking damage to the underlying tooth structure.

Other options, such as those involving polyacrylic acid, are typically used for different types of bonding procedures, such as using glass ionomer cements, and do not achieve the same level of enamel etching required for optimal adhesion of composite materials in the total etch technique.