## Core Concept
The CAD-CAM (Computer-Aided Design/Computer-Aided Manufacturing) system is a technology used in dentistry for designing and manufacturing dental restorations, such as crowns, bridges, and implants. This system relies on the use of computer software to design the dental prosthesis and a milling machine to fabricate it.

## Why the Correct Answer is Right
The correct answer, , involves the use of **zirconia**, a popular material in dental restorations due to its strength, durability, and aesthetic properties. Zirconia is often used in the CAD-CAM system because it can be precisely milled into the required shape and form, providing an accurate fit and excellent clinical outcomes.

## Why Each Wrong Option is Incorrect
* **Option A:** - This option is incorrect because, although some CAD-CAM systems do work with metals, the specific mention of does not directly relate to the common materials associated with CAD-CAM technology in dentistry.
* **Option B:** - This option is incorrect because, while wax is used in dentistry for various applications, it is not typically associated with the CAD-CAM system for fabricating final restorations.
* **Option D:** - This option is incorrect because glass is not commonly used in the CAD-CAM system for dental restorations, especially when compared to the popularity and versatility of zirconia.

## Clinical Pearl / High-Yield Fact
A key point to remember is that the CAD-CAM system allows for **in-office milling** of dental restorations, significantly reducing the need for laboratory submissions and temporary restorations. This technology has revolutionized dental practice by providing same-day restorations, improving patient satisfaction and workflow efficiency.

## Correct Answer: .