California Registered Dental Assistant (RDA) Written Practice Exam

In dental practice, when trimming models for procedures such as crafting custom trays or preparing diagnostic casts, the maxillary model is typically the first to be trimmed. This approach is taken because it provides a stable reference point for orientation and allows the dental professional to have a clear view of the occlusal plane. Starting with the maxillary model helps in achieving the correct anatomical relationships and ensures that the mandibular model can be accurately aligned to it afterward.

Trimming the maxillary model first can also aid in setting up the mandibular model, as the occlusion can be assessed and adjusted more effectively. The maxillary arch usually has unique landmarks, such as the tuberosities and the midline, which need to be clearly defined to inform subsequent trimming efforts regarding the mandibular arch. Consequently, this systematic approach makes for more efficient workflow and better fitting dental devices.