For long span distal extension bases where rigidity is critical the major connector of choice is:
**Core Concept**
The question is testing the student's knowledge of removable partial denture design principles, specifically the selection of a major connector for long span distal extension bases. In removable partial denture design, a major connector is a rigid component that connects multiple components or clasps together, and its selection depends on the location, size, and type of the denture.
**Why the Correct Answer is Right**
For long span distal extension bases, rigidity is critical to distribute the masticatory forces and prevent denture displacement. A rigid major connector, such as a metal clasp assembly, is used to ensure the stability of the denture. The metal clasp assembly provides a rigid connection between the clasp and the major connector, thus maintaining the integrity of the distal extension base.
**Why Each Wrong Option is Incorrect**
* **Option A:** A mucostatic impression is not a type of major connector, but rather an impression technique used to record the dimensions of the oral tissues.
* **Option B:** A precision attachment is a type of clasp assembly, not a major connector.
* **Option C:** A resilient liner is a type of material used to line the denture base for patient comfort, not a major connector.
**Clinical Pearl / High-Yield Fact**
When designing a removable partial denture for a long span distal extension base, always select a major connector that provides rigidity and stability to the denture. A metal clasp assembly is a suitable choice for this type of denture design.
**Correct Answer:** C. Metal clasp assembly.