In the future, we will use 3D printing and scanning tech for perfect shoes, shirts, and even braces. Take Curatio for instance. It is an innovative 3D hand scanner that relies on 32 cameras and laser projection to capture your hand in 3D. The lasers create reference points to enable the software to 3D visualize the scanned object.
Such a technology can be used to build perfectly fit hand braces. The above video provides more information on this 3D hand scanner.