National Dental Examining Board of Canada (NDEB) Practice Exam

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Master your National Dental Examining Board of Canada (NDEB) exams with our comprehensive practice guide. Achieve excellence in your dental certification with expertly crafted questions and detailed explanations.

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Trephination is indicated when

  1. Pus is trapped within bone

  2. There is an abscess on the gingiva

  3. A tooth needs to be extracted

  4. The patient has gingivitis

The correct answer is: Pus is trapped within bone

Trephination is a surgical method used to remove a piece of bone from the skull. It is typically done to relieve pressure on the brain or to access and remove pus from an infection. This means that the other options, such as a tooth extraction (C) or abscess on the gingiva (B), do not require trephination as they do not involve the skull or brain. Additionally, gingivitis (D) is a gum disease that does not involve bone and would not require trephination. Therefore, the only correct option is A, when pus is trapped within bone and trephination may be necessary to remove it.