SeanHurts,
Sorry about your injury.
Unfortunately, many patients who sustain a significant intraarticular distal radius fracture, never regain "normal" motion (or what it was before the injury). This is mainly due to the extensive scarring of the joint capsule and other soft tissues around the joint.
You are being a little impatient however. While it usually takes about 6 weeks for the bone to unite, it takes much longer for the soft tissues to heal and the scar tissue to mature and soften, sometimes many months. It varies, because each patient heals at their own rate.
And again, some patients regain motion, while others do not.
Your pronosupination has returned fairly quickly, mainly because that motion actually mostly comes from the elbow (head of the radius), with just some rotation at the DRUJ (distal radioulnar joint) of the wrist. And, as you have noted, extension is usually the most difficult to regain. This is not only due to the scarring, but due to the way the bony architecture of the wrist is constructed. The distal radius is normally tilted volarly (palmar) somewhat, so that flexion is easier to do than extension.
Dynamic bracing, itself, probably won't gain you a whole lot of motion, above what you can get with active therapy. Dynamic bracing is mostly used for situations like tendon injuries, where passive motion is desired.
Some patients can get a little more motion with the use of static bracing at the extremes (sometimes called turnbuckle braces) for extended periods (such as when sleeping). This static bracing places a continuous pressure (stretching) on the tissues. But, you have to have a brace made for both extension and flexion. And, they can be very uncomfortable.
But, the tried and true method of regaining motion is continued occupational therapy (hand therapy). Warming of the tissues before doing range of motion (ROM) will help, as warm tissues are more pliable and stretchable than cold ones. So, hot packs, hot bath, paraffin baths are all good for warming the tissues. You might look into getting a paraffin bath (they can be obtained at places like WalMart for not a large amount of money). The wax provides a warming of the tissues and are often used by hand therapists.
Then, the exercises you have mentioned. There is nothing really special about any of the exercises; it is just moving the wrist in all of the directions.
Hopefully, you were moving your fingers while you were in the cast, since surgery. We have our patients moving the fingers in the post-op recovery area and give them the "six pack" of finger motion to do six times a day while in the cast. If you have not been moving the fingers, you are sort of behind the eight ball already. The fingers get stiff and fibrotic very quickly. Though, sometimes that can be overcome with some diligent work.
But, again, it is not uncommon for the wrist joint to really sock in with scar tissue, how much, depends upon the patient's body. Some patients form abundant amounts of scar tissue.
The scar will mature and soften somewhat with time, during which it is important to be moving, so that it will stretch out as much as possible.
All you can do move and do it often. Placing a stretch at the extremes for a count of ten each time (using the other hand as you are doing).
Some patients, who have trouble doing therapy on their own, can benefit from the use of CPM (continuous passive motion). But, the machines for the wrist are not all that common and can usually only be found in large therapy departments. But, if you can do the therapy on your own, these usually don't provide anything above that.
Unfortunately, until we discover something to prevent extensive scarring after intraarticular fractures, decreased range of motion will continue to be a problem.
Keep working. It usually takes many weeks (sometimes months) of therapy before the final outcome is reached. You never know how much motion a patient will obtain, until they have finished therapy. Some patients surprise us, and regain a lot of motion. All you can do is keep working.
You should also start working on activities that you need to do in your occupation. (This is one reason why hand therapy is called occupational therapy.) You will be surprised, that motions you used to do without thinking about, will take some effort to do at first. You will have to relearn to do some of these activities. You may have to devise ways to get around your decreased motion. With elbow and shoulder motion, sometimes patients can make up for any deficits they have in the wrist.
Good luck. Keep working hard with therapy. It is going to take some time and effort, but you should be able to get back to what you need to do. It may not be exactly the way you did it before, but it should work.
Good luck, wishing you the best.
Saving 
