It is normal for some babies to have delay in teething and can be of few reasons. If this past the mark of 15 months then you should consult doctor and clear your doubt.
My baby has also no teeth yet she is already 14 months old,am also worried,when does your baby first tooth erupted
Here's the chart to give you better guideline the stages of teeth growing.
Visit your doctor
Priyanka Manickavasagan