It may be split on one side and have only a groove or indentation on the other side. On very rare occasions, when the bone is separated completely on both sides, the middle bony segment may grow beyond the limits of the alveolar arch and protrude forward and even downward. This middle segment of the alveolar bone is called the premaxilla. When this occurs, the treatment requires high expertise from the orthodontist and surgeon who place the premaxilla within the alveolar arch to assure normal dental occlusion. Orthodontic treatment starts as early as possible.
Lip repair is performed at approximately three months of age.
Depending on the position of the premaxilla, it may require surgical-orthodontic treatment and bilateral bone grafting at a later age. Bilateral Cleft of the Lip and Alveolus. There is a cleft on both sides of the lip which extends into each nostril and through the alveolus on each side. The prolabium is isolated in the middle and contains no miuscle or vermilion. Since the defect follows the philtral columns, the philtral columns are absent as is the Cupid's bow.