National Board Dental Hygiene Examination (NBDHE) Dental Hygienist Practice Test

If a dentist is placing a bonded filling, she will do which of the following to ensure the filling bonds to the tooth?

1. X-ray the tooth

2. Scrape the tooth

3. Polish the tooth

4. Etch the tooth

The correct answer is: Etch the tooth

When a dentist is placing a bonded filling, etching the tooth is a crucial step to ensure strong adhesion between the filling material and the tooth structure. Etching involves applying an acidic solution to the surface of the tooth, which creates micro-roughness by removing some of the enamel or dentin. This micro-roughened surface increases the surface area for bonding and helps the bonding agent to penetrate more effectively, thus improving the mechanical interlocking and chemical bonding with the composite material. By contrast, while other options might involve different dental procedures, they do not directly promote the bonding process of a filling material. X-raying the tooth is essential for diagnosis and assessment but does not contribute to bonding. Scraping the tooth could damage the enamel or dentin and is not a standard practice for enhancing bond strength. Polishing the tooth is typically performed to smooth surfaces or remove plaque but does not facilitate bonding in the way that etching does. Therefore, etching is the definitive step that optimizes the bond between the filling and the tooth.