A puppy typically has 28 teeth, whereas the average adult will have 42. Great Dane puppies start to lose their baby teeth as early as three months of age. Most teeth fall out on their own accord while eating or during play. Yet in some cases they remain, even though a permanent tooth is growing in. It is not a concern for a few days, but if the baby tooth remains for a week or more, it may need to be extracted by a veterinarian.