What type of retention occurs between the tooth and bonding agent?

Mechanical retention refers to the process by which a material, such as a bonding agent, adheres to a surface through mechanical interlocking. In the context of dentistry, when a bonding agent is applied to a tooth, it often fills microscopic irregularities and pits on the enamel and dentin surfaces. This interlocking occurs as the bonding agent flows into these irregularities and hardens, providing a strong connection between the tooth structure and the dental material.

This form of retention is crucial for achieving stability and longevity in various dental restorations and treatments, as it allows for an effective seal and reduces the likelihood of microleakage. Such mechanical retention contributes significantly to the overall success of composite resins and other bonded materials.

Other forms of retention, like chemical retention, involve the formation of bonds on a molecular level but do not rely on the physical interlocking that characterizes mechanical retention. Physical retention might imply a combination of forces but does not specifically address the established mechanical interlocking, while bonding retention is not a commonly used term in dental literature. Therefore, the emphasis on mechanical retention in the interface between the tooth and bonding agent appropriately captures the essence of how these materials work together in dental applications.