Three-dimensional analysis of casts of the maxilla in infants with cleft lip and palate

For the investigation of three-dimensional morphological changes in the max illa of children with cleft lip and palate, the use of two-dimensional cast analysis is inadequate. Since no standardised three-dimensional method has so far been available, a three-dimensional digital, computer-aided procedu re was developed to visualize and metrically analyse the growth of the eden tulous maxilla of infants with cleft lip and palate. Chronologically consec utive casts of the maxillas (obtained at the ages of one week, and three, s ix and twelve months) of five children with complete unilateral CLP were me asured optically with the instrument Micromeasure 70 (R). Following digitat ion, the casts were reconstructed in the computer, aligned and superimposed using the Orthosurf(R) program. The distances between the surfaces were th en measured; in addition, the surfaces were segmented perpendicular to the alveolar crest at reference points CL, C1', C2, C2' and I. The volumes of t he resulting segments were determined and compare with one another. Special ly designed software automated the following steps: 1. identification of re ference points; 2. alignment of the cloud of points in a system of coordina tes, and 3. identification of the alveolar crest. Our initial results show that (1) the new method enables Visualization of the extent and direction o f morphological changes of the mucosal surface, and (2) reproducible quanti fication of these changes via the determination of changes in the volume of defined alveolar segments. The three-dimensional. analysis presented here permits a comprehensive three-dimensional measurement of the models of the edentulous maxilla of infants with cleft lip and palate.