Tax Question for dentists?

I know 2 dentists that have an immense amount of "trainees" and "interns" in their offices. I'm wondering if the bother of training these newbies and waiting for their learning curves to flatten out far outweigh a tax deduction that these guys might be getting. Some of the "trainees/interns" are absolutely not suited for dentistry, but the docs continue to court them through dental isting schools (that charge up to 11K for a certificate). Is there a tax deduction for dentists/physicians if there are trainees/interns and a willingness to give back to the community? Thanks