Papers by Keyword: Dog

Abstract: Dogs underwent high-frequency automated tibia lengthening with the Ilizarov apparatus over a 1.8-mm hydroxyapatite-coated intramedullary titanium wire. Daily distraction was 3.0 mm with a fraction of 0.125 mm/h and continued ten days. The regenerate was well vascularized, had zonal structure and was of normal or hyperplastic type to the end of distraction. Osteogenesis was fast and complete. The wire served for both mechanical and biological reinforcement of the bone callus and provided reduction of external fixation time. Mean consolidation time with the apparatus on the limb was 13.83±4.02 days. Overall, external fixation index was 10.5 days/cm and 4.8 days/cm in the consolidation phase.

Abstract: The high dimension and complexity of feature descriptor of Scale Invariant Feature Transform (SIFT), not only occupy the memory spaces, but also influence the speed of feature matching. We adopt the statistic feature point’s neighbor gradient method, the local statistic area is constructed by 8 concentric square ring feature of points-centered, compute gradient of these pixels, and statistic gradient accumulated value of 8 directions, and then descending sort them, at last normalize them. The new feature descriptor descend dimension of feature from 128 to 64, the proposed method can improve matching speed and keep matching precision at the same time.

Abstract: The objective of this series of experiments was to evaluate the effect of bioceramic coatings/ incorporations on implant surfaces as a function of implant and surgical drilling design. Methods: A series of four in vivo studies were conducted utilizing the dog proximal tibia model. The models provided implants that remained from 2 to 5 weeks implantation time. The different studies comprised the placement of implants with intimate contact with bone following placement and implant designs that resulted in healing chambers. The various implant types presented surfaces with and without Ca- and P-based bioceramic incorporations. Biomechanical and histomorphometric measurements along with qualitative bone-implant interface morphology evaluation were performed. For all studies, one-way ANOVA at 95% level of significance was employed along with Tukey's post-hoc multiple comparisons. Results: Close contact between cortical and trabecular bone and all the different implant surfaces irrespective of implant fit (with and without healing chambers) showed that all surfaces were biocompatible and osteoconductive. In general, appositional bone healing was observed at all implant regions that were in intimate contact with bone immediately after placement, and an intramembranous-like healing occurred throughout the whole volume of the healing chambers. Irrespective of implant + surgical drilling design, the presence of Ca and P resulted in a bone morphology that showed primary osteonic structures at earlier times than uncoated surfaces. Conclusion: Irrespective of implant design and surgical drilling combination, the presence of Ca and P on the implant surface positively modulated early healing around endosseous implants.

Abstract: Among surface modifications commercially available for dental implants, the incorporation of bioceramic coatings is one of the most popular. However, concerns regarding the effectiveness of the bond between the metallic surface and the coating have led to the development of thin-film Ca- and P- based bioceramic coatings. The purpose of this study was to evaluate the early bone response to a thin ion bean deposited (Test) bioceramic implant surface compared to an alumina-blasted/acid-etched (Control) surface in a canine model. Results showed that although no difference in bone-to-implant (BIC) could be noted between the two different surfaces, more organized bone architecture was present around the Test implants in 4 weeks. Based on this observation, the incorporation of a thin- film bioceramic coating positively influenced bone healing around dental implants at early times.

Abstract: This Study is based on the search and selection of suitable bioceramic materials as bone substitute in cases where the osseous tissue is lost. A total of 42 pieces were used divided in 3 groups: 14 of Alumina (Al2O3), 14 of Zirconia (ZrO2) and 14 of Zircon (ZrSiO4). The bioceramic materials were inserted on 21 adult dogs divided in 3 groups of 7 animals, implanted on both sides of the jaw. The main objective of this work is to evaluate the ceramic-bone interface. The results obtained were verified through clinical, radiographic and histological exams at the 40th day of the postoperatory time. A fibrous capsule was found in 36% of the cases where ZrO2 was inserted in contraposition with the Al2O3 and the ZrSiO4 where the bone formation was verified in 100 % and 92 % respectively.