Grandaughter 17 months hasn't a tooth yet

she has been to a pediatric dentist several times,ex-ray showed that she has teeth but doesn't know why unable tobreak through the skin do you have any answers?

Well first of all, I suggest making a small edit to your post, seeing as teeth don't break through skin, they break through gum. Second of all, teething is important to bringing in baby teeth, as well as building strong gums, so you should buy a teething ring or something, just make sure she chews a lot (on soft things obviously). Some people just get their teeth later in life, it just happens.

Relax. I'm a mother of 3. My first born didnt get her first tooth (3 to be exact popped out at once) untill she was 23 months old!! I stressed, naturally as she was my first. However her pediatrician assured me that all was normal and perfectly fine. No special teething "exercises" or preperations needed!! Dr's orders only included that I should stop stressing over nothing! She 14 now with perfect teeth!