As a international student, I can assure the OP that if somebody doesn't get in, its probably not because an internatioal kid is taking up his/her spot.
I go to UC Davis, which consists of 1.6% of international students. That being said, I am absolutely positive that the number of international denal applicants are probably even less, why?
1. The pool of dental applicants also consists of those from CC and State school, which are not allowed to issue I-20 and therefore have no international students.
2. Some d-schools dont take international students (asdoh, UCLA etc)
3. Most d-schools require transciprt from US/Canadian Universities, so only the international applicants that went to schools in US are considered pretty much.
4. Even if they do get in and end up with DDS, they cannot practice in their own country, unlike PhD and Masters, which leave them less incentives to apply to US dental schools.
5. They have no state schools to fall back on, hence they must be more competitive to be considered acceptance.
6. Financing d-school is going to be extremely dificult for them, because their tuition is general higher, (I alreadypay 8000 a quarter in UCD, whereas residents pay 3000) and also because they cannot take out loans by themselves.
That being said, out of 10,000+ d-school applicants last year, there were probably less than 100 international students...and out of those, how many do you think are really "competitive"? Therefore, do you REALLY think accepting international students would have that much of an impact?