**Core Concept**
The concept of centric occlusion (CO) and centric relation (CR) is crucial in prosthodontics, particularly in edentulous patients. Centric occlusion refers to the occlusal contact between the maxillary and mandibular teeth when the mandible is in its most posterior position, while centric relation is the maxillomandibular relationship in maximum intercuspation when the condyles are in their most posterior and superior position.

**Why the Correct Answer is Right**
When centric occlusion is not equal to centric relation, it can lead to unstable dentures. This discrepancy can cause the dentures to shift or rotate, resulting in discomfort, difficulty in chewing, and overall poor denture stability. The reason behind this instability lies in the fact that the denture-bearing areas are subjected to abnormal forces, which can lead to tissue irritation, sore spots, and eventual denture failure.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to the concept of centric occlusion and centric relation. The relationship between the maxillomandibular joints and the occlusal contacts between the teeth is not related to the concept of proprioception.

**Option B:** This option is incorrect because it does not directly relate to the concept of centric occlusion and centric relation. While the temporomandibular joint (TMJ) is involved in the movement of the mandible, its position and function are not the primary factors influencing the relationship between CO and CR.

**Option C:** This option is incorrect because it is a distractor unrelated to the concept of centric occlusion and centric relation. The concept of prosthetic occlusion is related to the artificial occlusal relationship between the dentures, not the relationship between the maxillomandibular joints and the occlusal contacts between the teeth.

**Clinical Pearl / High-Yield Fact**
In edentulous patients, achieving a harmonious relationship between centric occlusion and centric relation is crucial for stable dentures. This can be achieved through proper denture design, occlusal adjustments, and maxillomandibular relationship recordings.

**Correct Answer:** C. **Discrepancy between centric occlusion and centric relation can lead to unstable dentures.**