Which type of handpiece is used for polishing and smoothing completed restorations?

The most suitable type of handpiece for polishing and smoothing completed restorations is the high-speed handpiece. This tool operates at a significantly higher rotational speed than other types, providing the precision and efficiency needed to achieve a smooth finish on restorative materials such as composite or amalgam.

High-speed handpieces are designed for specific dental procedures that require fine, detailed work, making them essential in the final stages of restoration work. Their performance allows dental professionals to effectively refine surfaces, removing any minor imperfections left after the initial restoration process.

The other options do not serve this purpose as effectively. Slow-speed handpieces are primarily employed for tasks such as removing decay or adjusting restorations, but they lack the speed and efficiency needed for polishing. Carbide burs are tools that might be used within a handpiece but are not handpieces themselves; they usually serve as the cutting instruments rather than the delivery mechanism for polishing actions.