Study Models provide a 3-D view of your teeth and bite. That way you can see any issues there are in your mouth that can help you in making an informed decision regarding your treatment options.
A wax-up can be done on the study model if your want to see what your veneers would look like on your own teeth. It can help you and Dr. Heit determine if certain treatment options are possible. For instance, if Dr. Heit recommends 4 or 6 veneers to close a big gap, a wax-up using only 4 teeth would be tried to see if the result is acceptable.
If it is hard for you to visualize whether it would look good in your mouth by just looking at the model, Dr. Heit simply makes a quick mould of the wax up and puts the teeth design right in your own mouth as a temporary, completely reversable process that allows you to have some control in determining your results before proceeding. You can even wear it home and get the opinions of all your friends and family.
This process is a nice way to help with the predictablility of your result.
The same holds true for cases that involve changing the bite to treat or prevent TMD. A fully reversable process can find the bite in the physiologic rest position of the jaw first so you can feel and Dr. Heit can measure where the end point is before any dentistry is even started. You can then 'feel over time' the final result of your porcelain or orthodontic treatment option before the work is decided on. This diagnostic process is called TENS and Orthotic.
Dr. Heit is open to questions regarding the procedures she does. Some people want only a few details and others need more before making their decision. Your job is to make sure you have all your questions answered.