What is an important characteristic of the gingival floor in a Class II preparation?

The gingival floor in a Class II preparation should be flat to ensure proper retention of the restoration and to facilitate adequate sealing of the margins. A flat surface provides a consistent area for the material to bond effectively with the remaining tooth structure. This is particularly important in preventing plaque accumulation and potential failure of the restoration.

In Class II preparations, which involve the proximal surfaces of posterior teeth, achieving a flat gingival floor can also help in achieving correct contours and contacts with adjacent teeth once the restoration is placed. This characteristic is crucial for both the functional and aesthetic success of the dental restoration.

Other shapes, such as rounded or angled, can hinder the effectiveness of the seal and provide inadequate support for the restoration, leading to possible complications. Elevating the gingival floor would disrupt the integrity of the preparation and could compromise the margin sealing and overall stability of the restoration.