Hello!
While I'm not pre-dent, I'm pre-med, and I'm currently applying while teaching in Asia. I'll be flying back for interviews...oh god, it's tomorrow now, isn't it! In addition, one of my parents was the Dean of Admissions at a dental school for almost a decade, so hopefully I can offer some advice!
Basically, applying from abroad sucks, but so far I've found it doable. While I'm sure that some schools will be more difficult than others, admissions staff are people and will generally be understanding of your situation (if you are applying from abroad, it's probably one of the things that made you stand out in the first place!) Particularly if you plan a date well in advance, I don't think most schools will have too much of a problem with it, and every school that's offered me an interview has let me choose dates that were the most convenient for me.
That being said, they really don't seem to be receptive of skype/phone interviews. Very few actually offer them, and to be honest, even the ones that do wouldn't look favorably upon them. After everything you've worked for, it would suck to put yourself at a disadvantage right at the finish line. There's really no way around making at least one trip back, and probably two, unless you get really lucky. When I told my boss that I wanted to return to the US, his gut reaction was definitely a big "NO." However, when I explained that it wasn't just for fun, that I was actually going to help my career, he took a completely different tone and my request was processed that day. Obviously, I don't know your work situation, but that has just been my personal experience.
I hope this helps! If you have any other questions, please let me know!
