Dental Assistant Practice Exam

What is the concentration range of phosphoric acid used in acid etching?

1. 10-20%

2. 20-30%

3. 30-50%

4. 50-70%

The correct answer is: 30-50%

The concentration range of phosphoric acid used in acid etching is typically between 30% and 50%. This concentration is effective for creating a micro-roughened surface on enamel and dentin, which is essential for improving the bonding of dental materials, such as composite resins or dental sealants. Using this concentration allows for optimal penetration and etching without excessively damaging the tooth structure. A phosphoric acid solution within this range provides sufficient strength to remove the smear layer and create the necessary surface profile for adhesion, while still being controllable during the etching process. Lower concentrations may not achieve the desired etching effect, whereas higher concentrations could potentially harm the integrity of the tooth surface. Understanding the role of phosphoric acid in dental procedures emphasizes the importance of using the correct concentration to ensure effective bonding and long-term clinical success in restorative dentistry.