This is the worst reasoning about the whole

thing I heared so far -- glad she is not my dentist! She might be a good dentist to you, but her claims as you described is just, well, wrong!

1. By simply looking at those pictures she can determine those teeth are baby(primary) teeth?

2. Basic human anatomy 101 here. During a "normal" smile, one will expose about 12 teeth -- 6 upper and 6 lower. They are the frontal and lateral incisors (8 of them, replaced by 8 years old already), and the 4 canines (replaced 9-12 yrs old). From those pictures, one can see less than 6 teeth. So those girls are around 8 years old?

BTW, please tell that dentist that she might have a stronger argument if she can see a missing tooth from the pictures because that means those girls have just sheded their baby teeth so they HAVE TO be less than 16 yrs old.

To answer your question: yes, there are methods to determine a person's age -- but not by looking at a randomly-taking picture.