Dental OSCE (Objective Structured Clinical Examination) Practice Exam

Before trimming teeth on a stone cast for an immediate denture, what must you mark?

1. A line 2 mm above the free gingival margin

2. A line 5 mm above the free gingival margin

3. A line 3 mm above the free gingival margin

4. A line at the free gingival margin

The correct answer is: A line 3 mm above the free gingival margin

Marking a line 3 mm above the free gingival margin on a stone cast before trimming teeth for an immediate denture serves an important purpose in the denture fabrication process. This distance is critical as it allows for adequate space for the acrylic material of the denture base and helps to ensure that the final prosthesis fits properly without impinging on the underlying gingival tissues. When the line is set at 3 mm, it creates a balance that accommodates any potential swelling or changes in soft tissue after tooth extraction. This ensures that the denture does not place excessive pressure on the healing gums, reducing the risk of discomfort or complications during the immediate post-operative period. Additionally, this measurement helps to align the denture with the anatomical position of the remaining soft and hard tissues, supporting both aesthetics and function. A line set too close to the free gingival margin could result in a denture that is too bulky or invasive, while a higher line may lead to unnecessary loss of tooth structure and impact denture stability. Therefore, the choice of marking a line 3 mm above the free gingival margin is based on achieving an optimal balance for comfort, fit, and function in immediate denture design.