When young children have a lot of cavities and their front teeth are decayed, often the front baby teeth have to be removed. This is actually not too hard for the kids but pretty hard on the parents because they are worried the missing teeth look bad and they are concerned about difficulty eating or speaking or having enough room for the permanent teeth to grow into the mouth.
Some background: the baby teeth (or milk teeth or primary teeth) grow in when a child is about 4 to 6 months of age until about 2 to 3 years of age. The front teeth are called incisors and they are usually the first to grow in and the first to fall out. The primary incisors normally start falling out starting age 6 with the lower central incisors, then the upper central incisors coming in about the same time as the lower lateral incisors (next to the central teeth) about age 7, and the upper lateral incisors usually come out about age 8. So the permanent incisors fall out starting about 6 and are usually all in by 8.
Most parents want the missing incisors replaced, if possible, and there are appliances to do just that. A fixed pedo partial (some call a Groper appliance) is a way to replace missing baby incisors with artificial teeth that do not come out until the permanent teeth start to grow in. This is different from a removable partial denture that can come out to be cleaned daily.
Making a fixed pediatric partial is done by taking an impression of the upper jaw and fitting orthodontic bands around the baby molars, sending the bands and impression to a laboratory for construction of artificial teeth attached by a thick wire to the molars.
These look great but there are some difficulties with them. First of all, all the upper baby molars must be erupted, usually by age 30 months. Next, the child must be fairly cooperative to get the impression of their teeth and upper jaw and even more cooperative to cement (glue) it into place. Many young children struggle to keep their fingers off of this new mouth toy and can pull on it enough to bend it out of shape. Finally, most dental insurance plans do not pay for the aesthetic replacement of missing baby teeth so it is paid for out of parent's pockets.
With all these challenges, almost all parents choose to wait for the permanent teeth to come in and not worry that their children look like a kindergartener, with an adorable gap-tooth smile.