This chapter provides a brief summary of the palate development and the craniofacial anomaly associated with the lip and palate. The depth of cleft palate and cleft treatment is beyond the scope of this textbook. However, a brief summary will aid in creating a better understanding of this aspect of orthodontics.

Palate Formation

The completion of the palate takes up to 12 weeks in utero and initiated by the sixth week of pregnancy. Two events occur for the maxilla to be structured:

1. Development of the maxillary alveolar process and the primary palate formation. The primary palate (also known as the premaxilla) is located anterior to the incisive foramen. These structures form the body of the maxilla. The medial and lateral nasal processes fuse with the maxillary processes.
2. Formation of the secondary palate as the lateral palatine shelves elevate and fuse (Figure 9.1). The secondary palate is located posterior to the incisive foramen and gives rise to the soft and hard palates. Any disturbances at this stage may cause a defect in the fusion of the plates and may result in a cleft palate.

Cleft lip and cleft palate are two distinct defects that commonly occur concomitantly (Figure 9.2). These defects occur when the merging between mesenchymal connective tissues during the embryonic development miscarries, resulting in malformation of the lip and/or the palate. If the medial nasal process fails to fuse with the maxillary process, a cleft in the lip develops which may be unilateral or bilateral (Figure 9.3). If the lip is only affected by this deformity, generally there are minimal dental concerns, although it may involve the alveolar process. A cleft in the palate can affect the alveolus, leading to other dental defects. Examples of the dental anomalies associated with cleft palate include hypodontia, hyperdontia, delayed eruption and enamel defects such as enamel hypoplasia. The shape of the cleft also affects the eruption pattern and alignment of the teeth.

Treatment of Cleft Palate