Development of intracranial relations in patients aged 10 to 18 years with clefts of the lip and palate, using cluster analysis.

The investigation is based on a longitudinal cephalometric investigation of lateral teleroentgenographic pictures of male patients with a complete unilateral cleft of the lip and palate. Using cluster analysis the authorsinvestigated the relationship of 75 craniofacial characteristics of size, shape and position during the time interval from 10 to 18 years of age. The main objective of the work was to characterize the development of intracranial relations during the pubertal spurt and compare the final condition in adulthood with a control group. The angle of the cranial base and its effect on the position of the mandibular joint did not change during the investigation period. The relationship between the rotation of the mandible and the Inclination of the upper alveolar process with the protrusion of different parts of the skeletal profile also remained constant. Up to adulthood, the rotation of the mandible developed independently of the sagittal intermaxillary relations. The relationship between the sagittal intermaxillary relations and other parts of the face did, however, change. Before the onset of puberty it was influenced most by the reduced length of the maxilla. The inadequacy of maxillary growth was balanced during this period by a change in the shape and position of the mandible. Its adaptative capacities could not compensate later for this uneven development of the jaws potentiated by the pubertal growth spurt. Due to this the intermaxillary relations deteriorated at the end of development in the majority of patients. The association of the restricted vertical maxillary growth with its retroposition was manifested only in adulthood. Intracranial relations of the control group differed from those in the group with clefts. Sagittal intermaxillary and dental relations were not associated in healthy men. As individual probands were not linked by any restriction of growth or development, no close relationship developed between the shape characteristics of the lower jaw, which is the main compensatory adaptative mechanism.