American Board of Orthodontics (ABO) Practice Exam

The mechanism of action for acid etching on enamel primarily involves the dissolution of inorganic components, which creates submicroscopic pores on the enamel surface. When a mild acid solution, such as phosphoric acid, is applied to the enamel, it selectively removes the mineral content—primarily hydroxyapatite—resulting in a roughened surface texture. This micro-roughness increases the surface area and promotes a stronger mechanical interlocking with bonding agents used in orthodontics and dentistry.

The creation of these submicroscopic pores is crucial for enhancing adhesion because it allows bonding agents to penetrate into the irregularities of the enamel surface, leading to a substantial increase in the bonding strength between the enamel and orthodontic materials, such as brackets. This process is fundamentally important for the success of orthodontic treatments, as it ensures the durability of the brackets and other attachments.

The other options describe processes that do not accurately reflect the primary action of acid etching. For example, while bonding strength is enhanced as a consequence of the etching process, it is not the mechanism of action itself. Similarly, the idea of creating micro-cracks in enamel is not correct, as the objective of acid etching is to create a micro-roughened surface rather than to introduce