What can result from excessive contamination of enamel before bonding?

Excessive contamination of enamel before bonding can lead to decreased bond strength because contaminants, such as saliva, blood, or debris, interfere with the adhesive's ability to properly adhere to the enamel surface. For effective bonding, the enamel must be clean, dry, and free from any substances that could act as a barrier between the enamel and the bonding agent. If the enamel is not adequately prepared and is contaminated, the bonding agent will not penetrate the enamel effectively, leading to a weaker bond that may compromise the durability and longevity of the restoration. This is a crucial consideration in dental procedures, as a strong bond is essential for the functionality and success of any restoration placed on the tooth.