National Dental Assisting Examining Board (NDAEB) Practice Exam

What is required before placing the final impression material in a smooth impression tray?

1. Lubricant

2. Adhesive

3. Water

4. Varnish

The correct answer is: Adhesive

The correct response is that adhesive is required before placing the final impression material in a smooth impression tray. When using a smooth tray, the adhesive ensures that the impression material adheres properly to the tray, preventing it from separating during the impression-taking process. This is particularly important because a dislodged impression can result in inaccuracies, leading to an improper fit for restorations or prostheses. Adhesives create a grip between the tray and the impression material, which contributes to a more accurate transfer of the oral structures. It's essential not to overlook this step, as it significantly affects the quality of the final impression. While lubricants may be used in certain scenarios to aid in the removal of the impression material or to prevent adherence, they are not typically required for final impressions in smooth trays, as they can actually compromise the accuracy of the impression. Water and varnish serve different purposes in dental procedures and do not play a role in ensuring the retention of the impression material in this context.