California Registered Dental Assistant (RDA) Written Practice Exam

Through what surface of the posterior tooth is the dentist likely to enter with a rotary bur for root canal therapy?

1. Buccal

2. Lingual

3. Occlusal

4. Distal

The correct answer is: Occlusal

The dentist is likely to enter through the occlusal surface of the posterior tooth with a rotary bur. This is because the occlusal surface is the top surface of the tooth that comes into contact with the opposing tooth during chewing, and root canal therapy requires access to the root canal which is located deep within the tooth. The other options, such as the buccal, lingual, and distal surfaces, do not provide adequate access to the root canal as they are either located on the cheek, tongue, or side of the tooth respectively. Therefore, the occlusal surface is the most appropriate entry point for the dentist to perform root canal therapy.