When the baby teeth start to come through (around six to nine months), the front teeth could have a gap and the fraenum may be attached low to the gum. In most cases, these gaps can close by themselves with growth and time.
In some cases of severe tongue-tie (a condition caused by a restrictive fraenum that stops the tongue from poking out past the lips), the fraenum may cause a gap in the front teeth of the lower jaw.
The fraenum inside the upper lip is a fold of skin that attaches the top lip to the upper gum. The most common cause of gapped front teeth is a fraenum that sits lower than usual and keeps the two top front teeth apart. A diastema is a gap or space between any two teeth, but it is particularly common between the upper front teeth.