Invisalign is great for arch expansion which can help give a wider "Hollywood" smile as well as make space to alleviate the crowding. It is hard to put an exact time on it but usually takes between 6 and 10 months.
Orthodontists receive an additional 2-3 years of education after dental school (during their residencies). They were also in the top 5-10% of their dental school classes. After that every patient that walks in the door is an orthodontic patient compared to the general dentist who sees a...
If your teeth are unusually small, it may not be aesthetically appealing to you to simply close the spaces. However, if they are narrow and all of your teeth are also smaller than typical, it may be perfectly acceptable for you to have the spaces closed.
If certain of your teeth are small...