Dental OSCE (Objective Structured Clinical Examination) Practice Exam

How much gutta-percha should remain at the apex when fitting a post?

1. 2 mm

2. 4-5 mm

3. No gutta-percha is necessary

4. 1 mm

The correct answer is: 4-5 mm

Maintaining 4-5 mm of gutta-percha at the apex when fitting a post is important for several reasons. This amount of remaining gutta-percha helps to ensure that the apical seal is preserved, which is crucial for preventing bacterial contamination from the oral cavity. The gutta-percha acts as a barrier that minimizes the risk of reinfection in the root canal system after endodontic treatment. Additionally, having a buffer of gutta-percha allows for better retention of the post while providing adequate support to the remaining tooth structure. It is important to retain some gutta-percha to maintain the integrity of the periapical tissues and to provide a certain level of cushioning that protects the apex from the stresses that may occur during functional loading of the tooth. In conclusion, retaining 4-5 mm of gutta-percha contributes to the long-term success of the tooth, as it supports the healing process and reduces the likelihood of complications resulting from insufficient sealing or structural integrity.