Lead to pain and infection. Early loss of primary molars can lead to space loss and orthodontic problems. Primary canines and molars stay in the mouth until between 9-12 years old. If you have a small cavity at age3- 4 and you leave it untreated it will turn into a big cavity and then you have a kid with a toothache and possible abscesses. Dental disease is the most common reason for a child missing school. What that tells us is that too many people think it’s overkill and unnecessary but it’s really not