Your child's baby teeth have been with them since birth. You became aware of this first set of teeth when your child began to teethe as an infant and until your child is about six years old these are the only teeth he or she will have. Baby teeth are terribly important to the proper development of a child's mouth and jaw.
They set the tone for everything that will come after them, but they are always temporary, and when your child reaches the right age you will begin to see these early teeth give way before the permanent teeth that will define his or her adult life. For most children, this is an important milestone.
Your child will probably lose that first tooth when they are between four and six years old. Before the tooth goes, the roots that hold it into place must dissolve and be reabsorbed into the child's mouth. This is what causes the loose tooth that provides so much color and excitement to your young child's life. By this point in your child's life, he or she should be brushing twice a day regularly and perhaps even flossing with a little help from you. You want your child to be well prepared to take care of the healthy new teeth that are now coming in because this is the last set that they will develop.
Feel free to use the eruption of a new tooth and the loss of the old one to bring up the topic of dental hygiene and review. If your child has not developed a loose tooth or lost a tooth by the time they reach their seventh year, make an appointment with the dentist just to check things out.
In all probability, your child is fine even if he or she hasn't lost that first tooth, but it is important to check the issue out early in case something needs to be done. Loosing teeth can be hard work. If that loose tooth seems to be stuck encourage your child to help it along. Fiddling with a loose tooth is fine, but don't yank or pull on it and don't tie it to a string and shut the door. Pulling a tooth prematurely can expose an undissolved root and expose your child to potentially dangerous infections.
If your child complains of toothache or pain then you will want to have the dentist look at that as well, but if your child complains of gum pain, then assume its simply the new tooth coming in. You can treat the pain with a child safe painkiller or a gum-numbing agent. From now on, your child's mouth will be a constant mix of teeth that are old and new, coming and going. The final permanent teeth will probably be in place by the time your child reaches twelve or thirteen years old and then, finally, their wisdom teeth will begin to come in their late teens and early twenties.