Prenatal indices for mandibular retrognathia/micrognathia.

OBJECTIVE: Micro- and retrognathia of mandibular origin may lead to life-threatening respiratory problems in connection with glossoptosis immediately after birth. Prenatal screening for this malformation is therefore increasingly important. Today this is accomplished by predominantly subjective standards. Objective criteria have been proposed but have not become established. We therefore made an effort to develop indices that would identify major skeletal discrepancies or micrognathia in as straightforward a fashion as possible during routine prenatal sonography. MATERIALS AND METHODS: Series of fetal jaw sonograms (Toshiba Aplio MX®) were obtained in 313 women with normal pregnancies from weeks 19-29 of gestation. Upper- and lower-jaw landmarks were interactively located on screen and evaluated for reproducibility. Linear parameters representative of maxillary and mandibular length (SpA'-SpP' and Rami-SymMe) were measured and related to femur length and gestational age. Based on these data, indices for maxillary, and mandibular length were derived and analyzed. RESULTS: High correlations were identified for mandibular length both with gestational age (R = 0.845; R(2) = 0.713) and with femur length (correlation coefficients (R) = 0.839; coefficients of determination (R(2)) = 0.704). For maxillary length, the respective correlation coefficients were 0.691 (R(2) = 0.477) and 0.656 (R(2) = 0.430). Estimates of mandibular and maxillary length based on gestational age and femur length were obtained by regression analysis. The mean bimaxillary length ratio was 0.628 ± 0.043. CONCLUSION: Maxillary and mandibular growth can be objectively evaluated via indices. It is conceivable to develop this approach into a sensitive and reliable method of prenatal jaw screening for major skeletal anomalies and congenital malformations.

Maxillary reaction patterns identified by three-dimensional analysis of casts from infants with unilateral cleft lip and palate.

OBJECTIVES: In order to visualize and quantify the direction and extent of morphological upper-jaw changes in infants with unilateral cleft lip and palate (UCLP) during early orthodontic treatment, a three-dimensional method of cast analysis for routine application was developed. In the present investigation, this method was used to identify reaction patterns associated with specific cleft forms. MATERIALS AND METHODS: The study included a cast series reflecting the upper-jaw situations of 46 infants with complete (n=27) or incomplete (n=19) UCLP during week 1 and months 3, 6, and 12 of life. Three-dimensional datasets were acquired and visualized with scanning software (DigiModel®; OrthoProof, The Netherlands). Following interactive identification of landmarks on the digitized surface relief, a defined set of representative linear parameters were three-dimensionally measured. At the same time, the three-dimensional surfaces of one patient series were superimposed based on a defined reference plane. Morphometric differences were statistically analyzed. RESULTS: Thanks to the user-friendly software, all landmarks could be identified quickly and reproducibly, thus, allowing for simultaneous three-dimensional measurement of all defined parameters. The measured values revealed that significant morphometric differences were present in all three planes of space between the two patient groups. Patients with complete UCLP underwent significantly larger reductions in cleft width (p<0.001), and sagittal growth in the complete UCLP group exceeded sagittal growth in the incomplete UCLP group by almost 50% within the first year of life. CONCLUSION: Based on patients with incomplete versus complete UCLP, different reaction patterns were identified that depended not on apparent severities of malformation but on cleft forms.