Which surface is typically the first to be restored in a class II prep?

In a Class II cavity preparation, which involves the restoration of carious lesions in posterior teeth affecting both the mesial and distal surfaces, the gingival floor is considered the first surface to be restored. This prioritization occurs because the gingival floor serves as the foundation for the restoration and is critical for achieving proper adaptation of the restorative material. Ensuring that the gingival floor is adequately prepared first allows for better sealing at the margins, minimizes the risk of voids, and promotes a strong bond between the tooth structure and the restorative material.

The axial wall is an important aspect of the preparation as well, but focusing on the gingival floor first helps establish the depth and outline of the restoration. Additionally, addressing the gingival floor first allows the clinician to evaluate any remaining tooth structure and caries that may still need removal. Starting here contributes to an overall successful and long-lasting restoration.