This study presents a novel design of a ceramic/polymer biphasic combination scaffold that mimics natural bone structures and is used as a bone graft substitute. To mimic the natural bone structures, the outside cortical-like shells were composed of porous hydroxyapatite (HA) with a hollow interior using a polymeric template-coating technique; the inner trabecular-like core consisted of porous poly(D,L-lactic acid) (PLA) that was loaded with dexamethasone (DEX) and was directly produced using a particle leaching/gas forming technique to create the inner diameter of the HA scaffold. It was observed that the HA and PLA parts of the fabricated HA/PLA biphasic scaffold contained open and interconnected pore structures, and the boundary between both parts was tightly connected without any gaps. It was found that the structure of the combination scaffold was analogous to that of natural bone based on micro-computed tomography analysis. Additionally, the dense, uniform apatite layer was formed on the surface of the HA/PLA biphasic scaffold through a biomimetic process, and DEX was successfully released from the PLA of the biphasic scaffold over a 1-month period. This release caused human embryonic palatal mesenchyme cells to proliferate, differentiate, produce ECM, and form tissue in vitro. Therefore, it was concluded that this functionally graded scaffold is similar to natural bone and represents a potential bone-substitute material.

PURPOSEThe purpose of this study was to determine the effect of changes in the horizontal plane angle on the mesiodistal width ratios of the maxillary anterior teeth during the acquisition of frontal view photographs, derive these ratios for Korean adults on the basis of the data obtained, and analyze them using the Golden Proportion as a reference.MATERIALS AND METHODSIn experiment I, 30 plaster casts were mounted on an articulator and positioned on the angle-measuring device with a center setting of 0°. The device was rotated to 10° in 1° increments in a counterclockwise direction. At each angle, photographs were obtained and analyzed. Experiment II was based on 60 patients who visited the Department of Prosthodontics at Kyungpook National University Dental Hospital from February 2012 to February 2015. The patients were divided into three groups [Male (M), Female (F), Total (M + F)]. Frontal views were obtained for all groups and analyzed.RESULTSFrom 1° to 10°, the relative mesiodistal width ratios for the maxillary anterior teeth showed no significant differences from those at 0°. In all three groups, the relative width ratio of the maxillary central incisor was smaller than that specified in the Golden Proportion; the opposite was true for the canine.CONCLUSIONOur results suggest that the mesiodistal width ratios of the maxillary anterior teeth do not follow the Golden Proportion in Korean adults, and that a change in the horizontal plane angle from 1° to 10° during frontal photography does not affect these ratios.

Critically sized bone defects are often compounded by infectious complications. The standard of care consists of bone autografts with systemic antibiotics. These injuries and treatments lead to donor site morbidity, antibiotic resistant strains of bacteria, and often end stage amputation. This study proposes an alternative to the autograft using a porous, hydroxyapatite (HA) scaffold evaluated with and without infection and antibiotics. Twenty‐four New Zealand white rabbits received either our HA scaffold or a pulverized autograft (PBA) within a surgically created critical‐sized defect in the femur. The two grafts were evaluated in either septic or aseptic defects and with or without antibiotic treatment. The HA scaffolds were characterized with micro computed tomography. Post‐euthanasia, micro computed tomography, histology, and white blood cells component analysis were completed. The HA had significantly greater (p < .001) mineralization to total volume than the PBA groups with 27.56% and 14.88%, respectively, and the septic HA groups were significantly greater than the aseptic groups both with and without antibiotics (p = .016). The bone quality denoted by bone mineral density was also significantly greater (p < .001) in the HA groups (67.01 ± 0.38 mgHA/cm3) than the PBA groups (64.66 ± 0.85 mgHA/cm3). The HA scaffold is a viable alternative to the bone autograft in defects with and without infection as shown by the quality and quantity of bone.

Copper (Cu) nanoparticles as the metal nanoparticles in the conductive ink were synthesized using electrochemical reaction. This method is characterized as the synthesis process without any metal salts and the post-treatment of washing and drying. It means that it does not need to consider about oxidized and agglomerated metal nanoparticles during the extra treatments. The Cu nanoparticles were synthesized in the various conditions of electrolyte to investigate the mechanism of the synthesis reaction of Cu nanoparticles. And also, the synthesized Cu nanoparticles were controlled the dispersion stability with the addition of dispersion agent such as PVP and Dextran. Finally, it was achieved the ink-jet printed Cu patterns using the synthesized Cu nanoparticles, and examined the morphology of the patterns.

The aim of this study was to design an abutment with an esthetic emergence profile contour using CAD technology and compare the stress distribution within the structure between the custom abutment and conventional abutment according to the screw tightening torque using 3D finite element analysis (FEA). The maximum tensile principal stress was found in the endpoint of the screw head and the start point of the screw line with regard to the application of the tightening torque of the screw. A similar pattern was observed in all of the following screws: 10N·cm, 20N·cm, and 30N·cm. The tightening torque of the screw had a significant impact on the changes in the stress of the abutment and screw fixture. This study also found that the condition in which the screw load was applied showed a more realistic description of the behavior of a single fixed dental implant than the condition in which the screw load was not applied. This study examined the optimal tightening torque value of the screw for the denture used in this study at a location slightly higher than 20N·cm. The difference in the custom abutment and conventional abutment did not have a significant impact on the supporting bone with regard to the external load. In regard to the stress occurring in the screw, the custom abutment had a lower degree of stress than the conventional type. Therefore, a screw fracture would occur less frequently in a custom abutment than a conventional abutment.