Anatomical and functional custom made restoration techniques with Direct Metal Laser Forming technology: systematic workflow and CAD-CAM

Introduction Bone defects are usually repaired by the body’s healing process itself. If severe fracture, tumor or infection occur on large bones, it poses a serious challenge to the regeneration ability of the bones. One of the latest advancement in medical science is the rapid prototyping technologies. Therefore, the aim of the present study was the developing and testing of a reliable workflow to fabricate custom-made grafts in the field craniofacial surgery. Material and Methods In this study 14 patients with different cranio-facial bone defects were enrolled. Two evaluation methods were associated to test the results of the workflow. Surveys were given to patients undergone surgery and their surgeons to have a subjective analysis of the workflow. For each patient the produced prosthesis was superimposed on the original prosthesis design, the displacement between was evaluated. Results Significant level of discomfort at 4 weeks after surgery compared to 2 days after surgery, aesthetic improvement significant improved 1 year after surgery compared to 4 weeks after surgery. Aesthetic improvement 1 year after surgery and aesthetic improvement according to expectations showed correlation, aesthetic improvement 1 year after surgery and aesthetic improvement according to expectations showed correlation. The mean distance of the printed model was significant smaller than the virtual model, with a mean difference of -0.075 mm. Conclusion According to the results of the present study custom made bone graft made with laser sintering technique represents a valid alternative to traditional bone grafts with high clinical accuracy and the advantage to avoid morbidity of the donor site or of the patient due to animal grafting

Total cross sections for positron scattering from H2 at low energies

This paper revisits positron scattering from molecular hydrogen, in an attempt to provide accurate total cross-section data against which theoretical calculations might be benchmarked. The present data were measured over the energy range 0.1–50 eV and, where possible, are compared to results from previous experiments and calculations. Agreement with the earlier data was typically very good at energies above 10 eV but becomes progressively more marginal as we go to lower energies. None of the current theories quantitatively reproduce our measurements over the entire energy range, although at a qualitative level the main features driving the scattering dynamics are apparent

Positron scattering from formic acid

We report on measurements of total cross sections for positron scattering from the fundamental molecule formic acid (HCOOH). In this case, the energy range of our experimental work is 0.3-50.2 eV. Our interpretation of these data was somewhat complicated by the fact that at room temperature, formic acid vapor consists of about 95% monomer and 5% dimer forms, so that the present cross sections represent an average for that ensemble. To assist us in interpreting the data, rigorous Schwinger multichannel level calculations for positron elastic scattering from the formic acid monomer were also undertaken. These calculations, incorporating an accurate model for the target polarization, are found to be in good qualitative agreement with our measured data, particularly when allowance is made for the target beam mixture (monomer versus dimer) in the experiment

Total cross section measurements for positron scattering from acetone

We report results from total cross section measurements for positron-acetone scattering. The energy range of these experiments was 0.2-23 eV, while the energy resolution of our positron beam was ~260 meV. The present data clearly highlight the important role played by the strong permanent dipole moment and significant dipole polarisability of the acetone molecule on the low-energy scattering dynamics of this system. For positron energies above about 6 eV the present data is found to be in quite good agreement with the only other total cross section results available in the literature from the Yamaguchi group, however, at lower energies the level of agreement is rather poor. To the best of our knowledge, no theoretical calculations are currently available for positron-acetone scattering