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In all, children have 20 baby teeth - 10 on the top and 10 on the bottom. These teeth act as placeholders for the adult teeth that grow in after the baby teeth fall out.
These come through at about 4 weeks old. Finally, the twelve Pre-molars which are the big 'double' teeth in the back of his mouth. There are three top and three bottom on each side of his jaw. These are usually all in place by 8 weeks of age. This makes a total of 28 'baby teeth' (aka 'milk' or 'deciduous' teeth), the image on the right shows how all of this looks and will help you identify your puppy's teeth properly.