Not sure how old your kids are, but they do need to use kids toothpaste up to 6 years of age at least, as adult toothpaste is apparently not suitable for their teeth. Here's some info about it from the Choice consumer site..
While it might be easy to dismiss cute, mini-sized tubes featuring cartoon characters, make no mistake: children’s toothpaste is necessary. For children 18 months to six years, the Australian Dental Association (ADA) recommends no more than a pea-sized smear of low-fluoride toothpaste on their brush. Adult-strength toothpaste is not suitable for children under the age of six (unless you live in a non-fluoridated area where it’s recommended to use adult-strength toothpaste).
Children’s’ toothpaste contains considerably less fluoride than the adult version, and too much fluoride can cause dental fluorosis, a condition where the teeth’s enamel surface appears mottled. Most dental fluorosis is very mild and doesn’t damage teeth, and occurs only during tooth development in early childhood, so older children and adults aren’t at risk.
Fluorosis levels have halved since the early 1990s, with the wider use of low-fluoride children’s toothpastes and recommendations that children use only very small amounts of it."