American Board of Dental Examiners (ADEX) Dental Hygiene Licensing Examination 2025 – 400 Free Practice Questions to Pass the Exam

The recommended measurement for the undercut when using a wrought wire clasp is 0.5 mm. This measurement is significant because it ensures adequate retention while facilitating proper adjustments and placement of the clasp.

A 0.5 mm undercut creates a balance between securing the prosthesis and avoiding excessive force that could damage the supporting tissues or create trauma during insertion or removal. Wrought wire clasps are designed to flex slightly, and this degree of undercut accommodates that flexibility, allowing for optimal performance in maintaining the stability of the partial denture.

Measurements that are either too small or excessively large, such as 0.01 mm or 1 mm, do not provide the same level of functional retention or may complicate the fitting of the clasp. A smaller undercut might not retain the clasp adequately, leading to slippage, while a much larger undercut could risk over-retention, making it difficult for the patient to remove the appliance comfortably. Thus, 0.5 mm is the ideal choice for ensuring effective and safe clasp retention.