**Core Concept**
High speed cutting of enamel is a process that involves the interaction of a dental instrument, typically a drill, with the hard, calcified structure of enamel. This process requires a thorough understanding of the mechanical and thermal properties of enamel, as well as the principles of cutting and removal.

**Why the Correct Answer is Right**
The correct mechanism for high speed cutting of enamel is **abrasion**. This process involves the removal of small particles of enamel through a combination of mechanical stress and thermal expansion. The high speed drill creates a zone of thermal expansion within the enamel, causing it to expand and become more susceptible to removal by the drill. As the drill removes small particles of enamel, the process of abrasion continues, allowing for efficient and effective cutting of the enamel.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because **erosion** involves the chemical dissolution of enamel by acids, which is not relevant to high speed cutting. Erosion is a separate process that occurs through chemical means, not mechanical.
**Option B:** This option is incorrect because **fatigue** refers to the weakening of a material due to repeated stress, which is not the primary mechanism for high speed cutting of enamel. While fatigue may play a role in the failure of dental instruments, it is not the primary mechanism for cutting enamel.
**Option C:** This option is incorrect because **plastic deformation** involves the permanent change in shape of a material under stress, which is not relevant to high speed cutting. While enamel may undergo some degree of deformation during cutting, it is not the primary mechanism for removing enamel.

**Clinical Pearl / High-Yield Fact**
To efficiently cut enamel, dental instruments should be used at high speeds (typically above 100,000 rpm) and with adequate coolant to prevent thermal damage to the enamel.

**Correct Answer: C.