Many qualified students don’t make it into dental school so don’t be too despondent. So what do you do? Perhaps apply again and improve in areas that were lacking such as DAT scores, grades, interview, etc. If you don’t get in the second time you may have to face the music and admit that you can’t cut the mustard. As an alternative you might consider the following:

• MBA/JD - combined with a science background you can do patent law, business development, investing, etc., all in a science atmosphere (biotech company). Law schools and MBA schools continue to admit tons of students.
• Optometry (less glamorous but it pays the bills)
• Pharmaceutical sales representative (quite lucrative)
• Research Associate (at a biotech company) and NOT at a University (low pay)