Which step is NOT typically included in preparing a veneer for diastema closure?

The correct choice indicates that terminating the preparation just facial to the proximal contact area is not typically included in the steps for preparing a veneer for diastema closure. When preparing a veneer, particularly for diastema closure, it's essential to ensure that the preparation allows for adequate bonding and strength.

The preparation should generally extend slightly into the interproximal areas to avoid undercuts and ensure that the veneer can be properly adhered. Terminating the preparation facial to the proximal contact area may limit the veneer’s ability to achieve an optimal seal and could compromise the aesthetic transition between teeth. Therefore, this step is often not included as it does not align with the overall goals of achieving a seamless and durable veneer placement.

In contrast, the other steps listed—facial surface reduction to a specified thickness, gingival margin reduction, and preserving the incisal edge—are all common practices that help facilitate proper adhesion, aesthetic outcome, and functional integration of the veneer. Each of these steps serves to create an appropriate environment for the veneer while ensuring that it aligns with the overall dental anatomy and occlusion, focusing on achieving a successful diastema closure.