Oral cleft volumetric assessment by 3D multislice computed tomographic images.

The aim of this study was to determine the quantitative assessment of bone volume defects using multislice computed tomography (CT), and to establish an image processing protocol that enables this analysis. Bone defects were created in nine dry skulls, to mimic oral clefts. All the defects were modelled with wax, following the contralateral shape of the alveolo-palatal region. The wax was used to obtain the real volume of the cleft (gold standard). The skulls (with and without wax) were submitted to multislice CT examination, and the images were processed in an independent workstation using volumetric software. All the images were analysed twice, by two examiners at different times, performing intra- and inter-examiner analyses. The results show that the protocol for image processing has high efficiency (P=0.995). Multislice CT showed excellent results, with high reliability in the study of bone defect volume (P=0.997). The intra- and inter-observer analysis showed no statistically significant differences. It was demonstrated that multislice CT is a reliable technique in the volumetric assessment of bone defects in the alveolar and palatal regions, and that this method was efficient for calculating the volume of the clefts.