National Dental Assisting Examining Board (NDAEB) Practice Exam

Cavity varnish is placed ____ the liner or insulating base.

1. Under

2. Over

3. Beside

4. Between

The correct answer is: Over

Cavity varnish is typically placed over the liner or insulating base in a dental restoration process. The primary purpose of cavity varnish is to seal the dentinal tubules and create a barrier that protects the underlying materials and the pulp from potential irritants and microleakage. By applying the varnish over the liner or base, it enhances the effectiveness of these materials by providing an added layer of protection. Applying the varnish over the liner also helps in ensuring that the varnish adheres properly and maximizes its sealing properties. This order of application is crucial because if it were placed beneath the liner or between layers, it would not serve its protective function effectively. The varnish’s role in promoting a moisture barrier and preventing chemical irritation is best achieved when it is in direct contact with the restorative material, thus solidifying its placement as the top layer.