The brain grows rapidly during the first 6 years of life and in turn, the cranium is growing, as well. This cranium growth influences the facial growth until about age 6 as this is when the cranium usually stops growing. However, the face continues to grow out from under the cranium until puberty.

After age 6, one of the key influences of facial growth is nasal breathing. In order for the face to grow as it should the tongue needs to be in the right position in the palate, the lips need to be sealed and breathing must be nasal. To achieve ideal function and aesthetics of the face these three things must happen during these key developmental years.