Earticle

Purpose: This study was performed to investigate mechanical properties of the porous Ti implants according to porosity. Porous Ti implant will be had properties similar to human bone such as microstructure and mechanical properties. Methods: Porous Ti implant samples were fabricated by sintering of spherical Ti powders(below 25 ㎛, 25~32 ㎛, 32~38 ㎛, and 38~45 ㎛) in a high vacuum furnace. Specimen’s diameter and height were 4 ㎜ and 40 ㎜. Surface and sectional images of porous Ti implants were evaluated by scanning electron microscope(SEM). Porosity and average pore size were evaluated by mercury porosimeter. Young’s modulus and tensile strength were evaluated by universal testing machine(UTM). Results: Porosity of Implant was increased according to larger particle size of the powder. Boundary portions of particles are sintered fully and others portions were formed pore. Young’s modulus was decreased by formed porous structure. Tensile strength was decreased according to larger the particle size of the powder, but higher than human bone. Conclusion: If prepared by adjust the porosity of the porous Ti implant will be able to resolve the stress shielding phenomenon.

Purpose: This study, it was observed on the effect of material and thickness of the mouth guard on postural balance in order to assess the influence of the use of a mouth guard. Methods: The mouth guards of 10 adults selected as the experiment subject was sorted into each of hard and soft material, and these were made as thickness of 2.0 ㎜, 2.5 ㎜, 3.0 ㎜, 3.5 ㎜ by each of the material. Results: The results of this study are expected to wear the mouthguard hard to influence positive influence on the improvement of the muscle strength, static balance. Conclusion: Suggest the need for additional research on dynamic balance.

Purpose: In this study, the marginal fitness of ceramic Co-Cr metal crown made by precision casting, milling, and selective laser melting method were compared. Methods: The ceramic Co-Cr metal crown manufactured by precision casting used the lost wax(LC specimen) method. The abutment were scanned and then made by milling(CM specimen), selective laser melting(CS specimen) method. The specimen were cut bucco-lingual and mesio-distal, and absolute marginal discrepancy and marginal gap were measured using a digital microscope. The surface roughness of the crown was also observed. Results: On the bucco-lingual axial, absolute marginal discrepancy was the LC specimen 31.72(±4.58)㎛, the CM specimen 78.29(±3.28)㎛ and the CS specimen 143.13(±3.83)㎛, respectively. On the bucco-lingual axial, marginal gap was the LC specimen 22.70(±1.46)㎛, the CM specimen 22.70(±1.49)㎛ and CS specimen 99.60(±1.57)㎛, respectively. Conclusion: For ceramic Co-Cr metal crowns, LC specimen was superior for absolute marginal discrepancy and marginal gap. The surface of metal crowns by selective laser melting were the roughest.

Purpose: The main purposes of this study are to describe the organization effectiveness and to investigate the effects of dental technicians’ work ethic on job satisfaction, organization citizen’s action, and organizational commitment. Methods: A total of 300 dental technicians working at dental laboratories in the Daegu area were randomly selected and surveyed, 298 of them were used for the statistical analysis. Results: The work ethic sub-items, such as industry, work centrality, morality, time save, independence, and relation with co-worker are independent variables. The organization effectiveness subi-items, such as job satisfaction, organization citizen’s action, and organizational commitment are dependent variables. Sociodemographic variables are used for control variables. Findings are as follows: First, in terms of dental technicians’ work ethic, the level of relation with coworker was the highest, and work centrality was the lowest. Second, in terms of dental technicians’ organization effectiveness, the level of citizen’s organizational action was the highest followed by organizational commitment and job satisfaction in order. Third, the effects of industry, work centrality, time save, relation with coworker, and morality showed statistically significant relationships with organizational effectiveness. Fourth, the effects of industry, work centrality, time save, relation with co-worker, and morality statistically significant relationships with job satisfaction. Fifth, in terms of organization citizen’s action, the effects of industry, work centrality, and time save were statistically significant. Sixth, work centrality, time save, relation with coworker, and independence were statistically significant with organizational commitment. Conclusion: Some policy implications for the improvement of organizational effectiveness are introduced and discussed. Dental technicians are required to have vocation and work ethic for themselves and the organization, and by doing so, they may contribute to the improvement of national oral health. Policies and educational programs, which can support them may be necessary.