hey butchh
as far as i knw the bench exam is a basic hand skill test conducted by some colleges to evaluate prospective dental students whereas a wreb is an exam for licensure to practice after u have completed ur education.
WREB member states are Alaska, Arizona, California, Idaho, Kansas, Missouri, Montana, New Mexico, Oklahoma, Oregon, Texas, Utah, Washington, and Wyoming. Other states currently accepting successful completion results of the WREB exam for licensure are Colorado, Connecticut, Iowa, Kentucky, Louisiana, Maine, Massachusetts, Nevada, New Hampshire, Ohio, South Dakota, Tennessee, Vermont, Virginia and West Virginia.
hope this helps....