• Journal of the Korean Society of Industry Convergence
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• v.5 no.2
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• pp.141-146
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• 2002

Stereolithography is the best known as rapid prototyping system. It uses the STL format data which is generated from CAD system. In this study, One of the main function of this developed CAM system deals with shape modification which divide a shape into two parts or more. The cross section of a STL part by a z-level is composed with nested or single polygonal closed loop. In order to make RP product, closed loops must fill with triangular facets from SSET and recover sliced triangular facets which is located normal direction to the cross sectional plane. The system is development by using Visuall C++ compiler in the environment of pentium PC. Operating system is Windows NT workstaion from Micro-Soft.

• Korean Journal of Materials Research
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• v.29 no.4
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• pp.221-227
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• 2019

This study examines the role of the nano- and micro-particle ratio in dispersion stability and mechanical properties of composite resins for SLA(stereolithography) 3D printing technology. VTES(vinyltriethoxysilane)-coated $ZrO_2$ ceramic particles with different nano- and micro-particle ratios are prepared by a hydrolysis and condensation reaction and then dispersed in commercial photopolymer (High-temp) based on interpenetrating networks(IPNs). The coating characteristics of VTES-coated $ZrO_2$ particles are observed by FE-TEM and FT-IR. The rheological properties of VTES-coated $ZrO_2/High-temp$ composite solution with different particle ratios are investigated by rheometer, and the dispersion properties of the composite solution are confirmed by relaxation NMR and Turbiscan. The mechanical properties of 3D-printed objects are measured by a tensile test and nanoindenter. To investigate the aggregation and dispersion properties of VTES-coated $ZrO_2$ ceramic particles with different particle ratios, we observe the cross-sectional images of 3D printed objects using FE-SEM. The 3D printed objects of the composite solution with nano-particles of 80 % demonstrate improved mechanical characteristics.

• Journal of Periodontal and Implant Science
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• v.37 no.4
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• pp.805-824
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• 2007

Purpose: Developments in micro/macrostructures of implants and surgical techniques brought out stable outcomes of implant dentistry. The aim of this study was to evaluate the distributions of implant patients, the types of implanted sites, and the success or survival rates of various implant systems and to analyze the implant placement done at each specificintraoral site and situation. Materials and Methods: The data of dental implantations collected between 1992 and 2006 at the Department of Periodontology in 00000 University Hospital were analyzed. Results: 1. Largest part of the patients were at the age of 40s and 50s in bothgender who lost their teeth mostly by periodontaldiseases and caries at the posterior intraoral sites as major ones. Bone densities of type II(mandible) and III(maxilla) were likely to be seen with quantity of type B. Lengths of the implants between 10 and 15 mm and wide platform took the largest part. 2. Survival rates of $Implantium^{(R)}(98.8%)$, $Xive^{(R)}(100%)$ and ITI $TE^{(R)}(100%)$ were high when $Frialit-2^{(R)}$ showed 82%(poor bone density area) or 87.2%(combined with additional therapy). $IMZ^{(R)}$ had lowest cumulative survival(67.5%) and success rate(49.4%) amongst all. 3. Replacement with 2 wide or 3 regular platforms showed no significant differences in survival rate and marginal bone loss atmandibular posterior area. In single restoration of mandibular second molar, 5-year success rate of machined surface $Br{\aa}nemark^{(R)}(70.37%)$ was lower than that of rough surface $ITI^{(R)}$ SLA(100%). 4. Replacement of single tooth in anterior area showed high survival rate of 94.5%. 5. The success rates of $Br{\aa}nemark$ Ti-Unite and ITI SLA at posterior maxilla with poor bone density both showed stable outcomes. 6. 10-year cumulative survival rate of implants with maxillary sinus augmentation by lateral window approach appeared to be 96.60%. Low survival rate(75%) was shown when there were more than two complications combined. Height of grafted bone remained stable above the implant apex. Conclusions : Rough surfaced implants showed stable outcomes in most of the situation including poor bone density and additional therapy combined.