I get asked the question above quite frequently. Since I love every minute of my job (sometimes a little too much!), discussing this with me may turn into a longer conversation than you bargained for. Let's try to get a feel for what is involved in becoming a specialist in orthodontics.
Since dentistry is quite a competitive field to enter, your grades are very important. High school grades are looked at somewhat by your future dental school but it is the grades you earn in college that are most important to being accepted into a fine school of dentistry. As we all know, good grades are hard to obtain in any class but especially in the more difficult prerequisites that are necessary for your dental school application. Biology, chemistry, calculus, physics, anatomy and physiology are some of the courses required at most dental schools. These classes can turn you into the roommate that has to hit the books Monday nights instead of watching Monday Night Football on ESPN.
You usually apply for dental school during your fourth year in college after taking the Dental Admissions Test (DAT) previous to that. This test is equivalent to the MCAT necessary for admission to medical school. The admission committees usually look not only at your grades and DAT score but also what other extracurricular activities you were involved in. Working and volunteering in dental offices is important so that you have a knowledge of the dental profession. The personal interview also helps to distinguish you from other "would be dentists".
Once you start dental school the grades there continue to be of prime importance. Now you are taking the same classes as most other students that will be competing against you for the orthodontic school positions available after finishing your four year dental training. Those accepted into an orthodontic residency tend to be in the very top of their dental class. Many of them have also built up a rather student loan amount which may continue to rise the added cost of the orthodontic training.
Most orthodontic training programs now require form 30 to 36 months after completing four years of dental school. However, this is where the fun starts because you have finally made it to the instruction for which you have been yearning (for the last 8 years of college!). My orthodontic residency at Mayo Clinic was for 36 continuous months with no breaks other than the holidays themselves.
College was fun, dental school was interesting and challenging while orthodontic "school" was the most intellectual fun I have ever had. I would not change a thing about the whole process and am truly thankful for every day I have spent in the orthodontic profession.