Papillon Puppies start getting their adult teeth by approximately 3-4 months of age. This teething stage, where puppy teeth are replaced by adult teeth, last about 3 months or so, during that time, just like a human baby, your puppy can have a sore mouth, and it may inflict their eating habits, if his mouth is really sore.
The shedding of the baby teeth and replacement with adult teeth end at about 8 months of age.
Most of the time, the puppy swallows the tooth, that is the reason, we never get to see them.
Retaining Puppy Teeth:
There are time when the baby teeth do not fall out, and the dog develops a double row of teeth.
Or you see a one adult tooth next to it's companion baby tooth. This can cause the adult tooth, or teeth being pushed out of alignment, which can cause malocclusion and gum injury.
Keep checking your your puppy's teeth, especially around the age of 6 months. If you see retained teeth, go to your vet; he will have the baby teeth removed.