Three-dimensional characterization of soft silicone elements for intraoral device

Hard X-rays tomography enables us to determine the shape and inner microstructure of a wide variety of solid states and their combinations. Biological samples, and in particular soft tissues from animals and humans, can be encapsulated in suitable containers to avoid deformations during the rotation and radiograph acquisition. The quantitative characterization of soft silicone objects, however, is challenging, because their shape depends on the orientation with respect to the gravitation force. Solid supports may help, but have some impact on the more or less complex-shaped silicone part. In medicine, silicone implants and devices play a major role, since the mechanical properties can be easily tailored. Using the nanotom® m (phoenix|x-ray, GE Sensing & Inspection Technologies GmbH, Wunstorf, Germany), we measured the X-ray absorption of silicone with pre-defined softness. The density resolution of the CT-system was insufficient to establish a density-stiffness relationship. In addition, the shape of a silicone part of a soft intraoral device was measured for three angles with respect to the gravitation force, for which the bending was obvious. These successful tomographic measurements will become the basis of finite element modeling to extract the mechanical properties including their local variations.