**Core Concept**
The ultimate strength of a material, in this context, refers to the maximum stress that a tooth or dental restoration can withstand before failing or fracturing. This concept is crucial in dentistry as it helps determine the durability and longevity of various dental materials and appliances.

**Why the Correct Answer is Right**
The ultimate strength of a material is directly related to its ability to resist deformation and fracture. It is measured by applying a gradually increasing load until the material fails. In dentistry, the maximum stress a tooth can bear before fracturing is influenced by factors such as the type of tooth, the presence of any pre-existing cracks or defects, and the forces applied to the tooth. The ultimate strength of a tooth is often assessed using mechanical testing methods, which provide valuable information for dental restorations and prosthetics.

**Why Each Wrong Option is Incorrect**
**Option A:** Stress at the point of fracture refers to the breaking strength of a material, which is not the same as ultimate strength. Breaking strength is the stress at which a material fails, whereas ultimate strength is the maximum stress a material can withstand before failing.

**Option B:** Total energy stored in the body at the point of fracture is not a relevant concept in this context. Energy is related to the deformation of a material, but it is not directly related to the ultimate strength of a material.

**Option D:** None of the above is incorrect because option C is a correct description of ultimate strength.

**Clinical Pearl / High-Yield Fact**
When assessing the ultimate strength of a tooth or dental restoration, it is essential to consider the type of force applied, the direction of the force, and the duration of the force. This information can help dental professionals determine the most suitable materials and designs for various dental applications.

**✓ Correct Answer: C. Maximum stress beared by body before fracture.**