INTRODUCTION: Cervical vertebrae shape has been proposed as a diagnostic factor for assessing skeletal maturation in orthodontic patients. However, evaluation of vertebral shape is mainly based on qualitative criteria. Comprehensive quantitative measurements of shape and assessments of its predictive power have not been reported. Our aims were to measure vertebral shape by using the tools of geometric morphometrics and to evaluate the correlation and predictive power of vertebral shape on skeletal maturation. METHODS: Pretreatment lateral cephalograms and corresponding hand-wrist radiographs of 98 patients (40 boys, 58 girls; ages, 8.1-17.7 years) were used. Skeletal age was estimated from the hand-wrist radiographs. The first 4 vertebrae were traced, and 187 landmarks (34 fixed and 153 sliding semilandmarks) were used. Sliding semilandmarks were adjusted to minimize bending energy against the average of the sample. Principal components analysis in shape and form spaces was used for evaluating shape patterns. Shape measures, alone and combined with centroid size and age, were assessed as predictors of skeletal maturation. RESULTS: Shape alone could not predict skeletal maturation better than chronologic age. The best prediction was achieved with the combination of form space principal components and age, giving 90% prediction intervals of approximately 200 maturation units in the girls and 300 units in the boys. Similar predictive power could be obtained by using centroid size and age. Vertebrae C2, C3, and C4 gave similar results when examined individually or combined. C1 showed lower correlations, signifying lower integration with hand-wrist maturation. CONCLUSIONS: Vertebral shape is strongly correlated to skeletal age but does not offer better predictive value than chronologic age.

Abstract Pataky, K., Villanueva, G., Liani, A., Zgheib, O., Jenkins, N., Halazonetis, D. J., Halazonetis, T. D. and Brugger, J. Microcollimator for Micrometer-Wide Stripe Irradiation of Cells Using 20-30 keV X Rays. Radiat. Res. 172, 252-259 (2009). The exposure of subnuclear compartments of cells to ionizing radiation is currently not trivial. We describe here a collimator for micrometer-wide stripe irradiation designed to work with conventional high-voltage X-ray tubes and cells cultured on standard glass cover slips. The microcollimator was fabricated by high-precision silicon micromachining and consists of X-ray absorbing chips with grooves of highly controlled depths, between 0.5-10 microm, along their surfaces. These grooves form X-ray collimating slits when the chips are stacked against each other. The use of this device for radiation biology was examined by irradiating human cells with X rays having energies between 20-30 keV. After irradiation, p53 binding protein 1 (53BP1), a nuclear protein that is recruited at sites of DNA double-strand breaks, clustered in lines corresponding to the irradiated stripes.

OBJECTIVE: Fluctuating dental asymmetry is considered a sensitive indicator of environmental stress. We used fluctuating asymmetry of teeth in Greek children to assess the effect of the Chernobyl accident to the Greek population, which received relatively large radiation exposure compared to other European countries. DESIGN: Sixty dental casts were divided into two groups according to date of birth prior to or after the Chernobyl accident. The intercuspal distances of the mandibular first permanent molars were measured with digital calipers. We followed the data analysis procedure proposed by Palmer and Strobeck (2003). RESULTS: Fluctuating asymmetry was found at levels above measurement error in all traits except for the buccal measurement. Overall, there were no significant differences in the fluctuating asymmetry between the two groups, after removal of outliers. CONCLUSIONS: These results suggest that environmental radioactivity from the Chernobyl incident did not significantly affect the symmetry of lower permanent molar intercuspal distances in the specific population, even though increased levels of radionuclides have been reported in teeth and other tissues.

This case report describes the treatment of a patient whose maxillary left first premolar was impacted horizontally, and both maxillary canines were transposed relative to the first premolars. The patient was treated without extractions, and both canines were brought to their correct positions in the maxillary arch. Treatment mechanics during the various stages are discussed.