California Registered Dental Assistant (RDA) Written Practice Exam

The dentist uses a diamond bur to reduce the height and contour of a tooth for casting because diamond burs are specifically designed for efficient cutting and shaping of dental hard tissue. They are made with diamond particles that provide a rough texture, allowing for precise adjustments in contour and height. This is essential, especially in restorative procedures, where accurate tooth preparation is crucial for the fit and function of the cast restoration.

Diamond burs come in various shapes and grits, enabling dentists to achieve specific contours as needed. Their use in procedures like crown and bridge preparations is common because they can quickly and effectively remove enamel and dentin while providing a smooth surface suitable for casting.

While other tools like hand files, slow-speed rotary instruments, and chisels are available and used for various purposes in dentistry, they do not offer the same level of efficiency and precision in contouring and height reduction as diamond burs do in this specific context.