Great detective work! Who assigned you to be Sherlock Holmes? I am sure that you did the world and to that other student a grand favor! You sure taught her a lesson. You and I both know, I did not teach that girl a lesson. She taught herself a lesson.
Personally, I am not a fan about this snitching business- dental school applications, homework, essays or whatever the case. This just reminds me of a an incident in DS Anatomy class, where this one classmate never came in for cadaver lab, and there was one guy telling another guy in our class to snitch on the frequently absent student because it was a mandatory lab. Hmm... Would I be doing society a favor for snitching? So that my classmate can learn a lesson in life- not to cheat or cut corners?
Don't worry about other people. Worry about yourself. You can't change the world by snitching on a fellow. 60 hrs or 1000 hrs of shadowing a dentist- this is not the main thing that got your friend's friend into "multiple schools". I am sure his application had more to offer. How can you be sure their application had so much to offer when they were quick to lie on it? Obviously they did not feel that their application was sufficient, why should you?
On last note, quite frankly I don't give a rats azz if my dentist can't write essays or didn't conduct "extensive" research. I want my dentist to do a good job on my teeth! IMHO