What type of saw blade has a heat-treated tooth edge?

The correct answer is the type of saw blade that features a heat-treated tooth edge is the hard-edge, flexible-back blades. This treatment enhances the hardness and wear resistance of the blade's edge, making it suitable for cutting through various types of materials with greater efficiency and durability. The heat treatment process allows the teeth to withstand higher temperatures generated during cutting, reducing the likelihood of wear and prolonging the life of the blade.

Hard-edge, flexible-back blades are designed to flex slightly during cutting, which allows for smoother cuts and better performance in a variety of applications, particularly in metalworking and woodworking. This combination of properties makes them ideal for tasks that require precision and the ability to handle different materials effectively.

In contrast, other types of blades mentioned may not specifically feature a heat-treated tooth edge or are designed for different purposes, which is why they are not the correct answers in this context.