**Core Concept**
The vertical dimension of occlusion is a critical concept in prosthodontics and restorative dentistry, referring to the optimal position of the mandible in relation to the maxilla during rest or function. The established vertical dimension freeway space is a key component of this concept, representing the difference between the rest position of the mandible and the position of maximum intercuspation.

**Why the Correct Answer is Right**
The established vertical dimension freeway space, also known as the rest position, is typically measured between 4-6 mm in most adults. This measurement is essential for proper occlusion and to prevent excessive wear on the teeth and surrounding tissues. The freeway space is determined by the anatomical relationship between the mandible and the maxilla, including the position of the condyles in the glenoid fossae and the length of the mandibular and maxillary dental arches.

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect, as 2 mm is generally considered too small for a freeway space, potentially leading to excessive wear on the teeth and surrounding tissues.
**Option B:** Incorrect, as 10 mm is generally considered too large for a freeway space, potentially leading to instability and discomfort during function.
**Option C:** Incorrect, as 0 mm is generally considered too small, potentially leading to excessive wear on the teeth and surrounding tissues.

**Clinical Pearl / High-Yield Fact**
A useful mnemonic for remembering the established vertical dimension freeway space is "4-6 mm: the magic number for a healthy occlusion."

**Correct Answer:** C. 5 mm