To access, purchase, authenticate, or subscribe to the full-text of this article, please visit this link: http://dx.doi.org/10.1016/j.prosdent.2017.05.009 Byline: Ayca Tulga, DDS, PhD [email@example.com] (*) Abstract Statement of problem An annealing procedure is a heat treatment process to improve the mechanical properties of cobalt-chromium (Co-Cr) alloys. However, information is lacking about the effect of the annealing process on the bonding ability of ceramic to Co-Cr alloys fabricated by rapid prototyping. Purpose The purpose of this in vitro study was to evaluate the effects of the fabrication techniques and the annealing procedure on the shear bond strength of ceramic to Co-Cr alloys fabricated by different techniques. Material and methods Ninety-six cylindrical specimens (10-mm diameter, 10-mm height) made of Co-Cr alloy were prepared by casting (C), milling (M), direct process powder-bed (LaserCUSING) with and without annealing (CL+, CL), and direct metal laser sintering (DMLS) with annealing (EL+) and without annealing (EL). After the application of ceramic to the metal specimens, the metal-ceramic bond strength was assessed using a shear force test at a crosshead speed of 0.5 mm/min. Shear bond strength values were statistically analyzed by 1-way ANOVA and Tukey multiple comparison tests ([alpha]=.05). Results Although statistically significant differences were found among the 3 groups (M, 29.87 [plus or minus]2.06; EL, 38.92 [plus or minus]2.04; and CL+, 40.93 [plus or minus]2.21; P=.002), no significant differences were found among the others (P>.05). The debonding surfaces of all specimens exhibited mixed failure mode. Conclusions These results showed that the direct process powder-bed method is promising in terms of metal-ceramic bonding ability. The manufacturing technique of Co-Cr alloys and the annealing process influence metal-ceramic bonding. Author Affiliation: Assistant Professor, Department of Prosthodontics, Faculty of Dentistry, University of Ordu, Ordu, Turkey * Corresponding author: Dr Ayca Tulga, Department of Prosthodontics, University of Ordu, Faculty of Dentistry, Guzelyali Mah. 94. Sk. No: 2, 52100 Ordu, TURKEY
Byline: Tingfang Sun, Kui Zhou, Man Liu, Xiaodong Guo, Yanzhen Qu, Wei Cui, ZengWu Shao, Xianglin Zhang, Shuyun Xu Keywords: extrusion free-forming; sintering temperature; nano-hydroxyapatite; bone morphogenic protein 2-related peptide; bone regeneration; repetitive acidic amino acid Abstract Extrusion free-forming, as a rapid prototyping technique, is extensively applied in fabricating ceramic material in bone tissue engineering. To improve the osteoinductivity of nano-hydroxyapatite (nHA) scaffold fabricated by extrusion free-forming, in this study, we incorporated a new peptide (P28) and optimized the superficial microstructure after shaping by controlling the sintering temperature. P28, a novel bone morphogenic protein 2 (BMP-2)-related peptide, was designed in this study. Analysis of the structure, physicochemical properties and release kinetics of P28 from nHA sintered at temperatures ranging from 1000 [degrees]C to 1400 [degrees]C revealed that nHA sintered at 1000 [degrees]C had higher porosity, preferable pore size and better capacity to control P28 release than that sintered at other temperatures. Moreover, the nHA scaffold sintered at 1000 [degrees]C with P28 showed improved adhesion, proliferation and osteogenic differentiation of MC3T3-E1 cells compared with scaffolds lacking P28 or BMP-2. In vivo, nHA scaffolds sintered at 1000 [degrees]C with P28 or BMP-2 induced greater bone regeneration in critical-sized rat cranial defects at 6 and 12 weeks post-implantation compared with scaffolds lacking P28 or BMP-2. Thus, nHA scaffolds sintered at 1000 [degrees]C and loaded with P28 may be excellent biomaterials for bone tissue engineering. Copyright [c] 2016 John Wiley & Sons, Ltd. Article Note: Tingfang Sun and Kui Zhou contributed equally to this study.
Ciocca, L., Fantini, M., Crescenzio, F., Corinaldesi, G., and Scotti, R.
Medical & Biological Engineering & Computing. Nov 2011, Vol. 49 Issue 11, p1347, 6 p.
Rapid prototyping -- Analysis, Implants, Artificial -- Analysis, Prosthesis -- Analysis, Sintering -- Analysis, Titanium -- Analysis, Universities and colleges -- Analysis, and Air pollution -- Analysis
This study describes a protocol for the direct manufacturing of a customized titanium mesh using CAD--CAM procedures and rapid prototyping to augment maxillary bone and minimize surgery when severe atrophy or post-oncological deformities are present. Titanium mesh and particulate autogenous plus bovine demineralised bone were planned for patient rehabilitation. Bone augmentation planning was performed using the pre-op CT data set in relation to the prosthetic demands, minimizing the bone volume to augment at the minimum necessary for implants. The containment mesh design was used to prototype the 0.6 mm thickness customized titanium mesh, by direct metal laser sintering. The levels of regenerated bone were calculated using the post-op CT data set, through comparison with the pre-op CT data set. The mean vertical height difference of the crestal bone was 2.57 mm, while the mean buccal-palatal dimension of thickness difference was 3.41 mm. All planned implants were positioned after an 8 month healing period using two-step implant surgery, and finally restored with a partial fixed prosthesis. We present a viable and reproducible method to determine the correct bone augmentation prior to implant placement and CAD--CAM to produce a customized direct laser-sintered titanium mesh that can be used for bone regeneration.
The development of tissue engineering constructs (TEC) from three-dimensional (3D) biodegradable matrices, which are resorbed in vivo with the repair of the damaged, is one of the main trends in [...] We studied the biocompatibility of porous polylactide carrier matrices obtained by means of surface selective laser sintering. Carrier matrices had no cytotoxic activity, but maintained adhesion and proliferation of cells. Subcutaneous transplantation of tissue engineering constructions from these carriers and bone marrow-derived multipotent stromal cells did not cause the inflammatory response and pathological changes in rats. The conditions for organotypic regeneration were provided at the site of transplantation (high degree of blood supply and considerable amount of immature precursor cells). Key Words: tissue engineering construction; polylactide carriers; selective laser sintering; multipotent stromal cells; regeneration