Cross Sectional Analysis of Eurasian Skull Anatomy for 3D Cephalometry-Normative Data Reveal Four Different Skull Types.

The unsolved problem in three-dimensional surgical planning for patients with facial deformity, dysgnathia, or asymmetry is the lack of a normative database of "norm skulls" that can be used as treatment objectives. A study was conducted on 90 Eurasian persons (46 male and 44 female adults) for whom cone beam-computed tomography images were available. Inclusion criteria were adult patients with a skeletal Class I pattern, proper interincisal relationship with normal occlusion, the absence of an open bite both in the anterior and posterior region, and a normal and balanced facial appearance; patients with dysgnathia and malformations were excluded. A total of 18 landmarks were digitized and 3D cephalometric measurements were performed and analyzed by means of proportions calculated from the landmarks. Male and female skulls were analyzed, as well as subdivisions revealed by cluster analysis. The data showed that four subtypes of skulls were distinguishable with statistical significance (p < 0.05). A male and a female type subdivided in a brachiocephalic and dolichocephalic phenotype could be identified. For each type, a mean shape was calculated by a Procrustes transformation, which, in turn, was used to create four template skulls from a male and a female skull. This was accomplished by fitting the polygon models of the two skulls to each of the two subtypes based on the landmarks marked on them using a thin plate spline transformation. The normative data of the subtypes can individually serve as a guide for orthodontic surgery in the Eurasian population, which is especially helpful in 3D planning and the execution of craniofacial operations.

Assessment of facial and cranial symmetry in infants with deformational plagiocephaly undergoing molding helmet therapy.

OBJECTIVES: The aim of this study was to determine the effects on facial and cranial symmetry through molding helmet therapy in infants with positional plagiocephaly. A 3D asymmetry index (3DAI), which measures both cranial and facial symmetry, was introduced and compared to the Cranial Vault Asymmetry Index (CVAI). MATERIAL & METHODS: Optical 3D-scans of children with positional plagiocephaly were evaluated retrospectively. Pre- and post-therapeutic asymmetry values of the cranium and face were determined and paired t-tests were applied. Pearson correlations were calculated for facial and cranial asymmetries. RESULTS: 65 children (age: 3-6 months) were included. Asymmetry values (mean/standard deviation, pre- and post-therapeutic) were for 3DAI determinations: cranium: 9.96/1.84-8.11/1.74 p < 0.001; face: 4.70/1.06-3.89/0.91 p < 0.001; and for CVAI measurements: 9.10/3.29-5.88/2.78 p < 0.001. No correlation was found between facial and cranial asymmetry (p > 0.05). CONCLUSION: Symmetry values improved significantly in post therapeutic 3D-scans for both asymmetry indices. The analysis of cranial symmetry by 3DAI should be preferred over the CVAI because it gives more comprehensive information, including the symmetry of the entire cranial surface and the face.