What type of repair technique uses heat to restore the shape of metal?

The technique that uses heat to restore the shape of metal is Paintless Dent Repair (PDR). This method involves applying controlled heat to the affected area of the metal, which causes it to expand and then return to its original shape as it cools down. By carefully manipulating the metal from behind using specialized tools, the technician can eliminate dents without the need for additional painting or extensive bodywork. This approach preserves the vehicle's original finish and is particularly effective for minor dents and dings.

The other options involve different processes. Spot welding is a joining method that creates a bond between two metal surfaces by using electrical resistance and does not address shaping the metal. Plastic welding is applicable to plastic materials, not metal, and is used to join plastic parts. Laser welding uses a high-energy laser beam to join metals but is not primarily aimed at restoring the shape of the metal like PDR does. This distinction highlights why Paintless Dent Repair is the correct choice when discussing techniques specifically aimed at restoring the shape of metal using heat.