Which type of brush is attached to a prophy angle slow-speed handpiece?

The correct answer is the flat-end brush. This type of brush is specifically designed to be used with a prophy angle slow-speed handpiece during dental prophylaxis. The flat-end brush's shape is ideal for effectively polishing the surfaces of the teeth, particularly in a manner that can reach the contours of the tooth surface.

Using a flat-end brush allows for adequate coverage and efficiency, as it can effectively clean and polish multiple surfaces of the teeth at once, which is essential during dental cleanings. In contrast, the other brush types do not provide the same benefits for polishing in a dental setting.

To summarize, the flat-end brush is essential for achieving optimal results during dental procedures involving tooth polishing, making it the preferred choice for use with a prophy angle slow-speed handpiece.