• The Journal of Korean Academy of Prosthodontics
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• v.44 no.6
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• pp.712-721
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• 2006

Statement of problem. Acrylic resin is most commonly used for denture bases. However, acrylic resin has week points of volumetric shrinkage during polymerization that reduces denture fit. The expandability of POSS (Polyhedral Oligomeric Silsesquioxane) containing polymer could be expected to reduce the polymerization shrinkage of denture bases and would increase the adaptability of the denture to the tissue. Purpose. The purpose of this study was to compare the dimensional stability in the conventional acrylic resin base, POSS-containing acrylic resin base, and metal bases. Materials and methods. Thirty six maxillary edentulous casts and dentures of different base were fabricated. Tooth movement and tissue contour change of denture after processing (resin curing, deflasking, decasting and finishing without polishing) and immersion in artificial saliva at $37^{\circ}C$ for 1 week and 4 weeks were measured using digital measuring microscope and threedimensional laser scanner. Results. The results were as follows: 1. The conventional resin group showed significant (p<0.01) dimensional change throughout the procedure (processing and immersion in artificial saliva). 2. After processing, the metal group and POSS resin group showed lower linear and 3-dimensional change than conventional resin group (p<0.01). 3. There was no statistically significant linear and 3-dimensional change after immersion for 1 week and 4 weeks in metal and POSS resin group. 4. In all groups, the midline and alveolar ridge crest area presented smaller 3-dimensional change compared with vestibule and posterior palatal seal area after processing and soaking in artificial saliva for 1 week and 4 weeks (p<0.01). Conclusion. In this study, a reinforced acrylic-based resin with POSS showed good dimensional stability.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.669-670
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• 2015

Efficient management of the construction heavy equipment is required to reduce the rate of carbon emissions and on-site accidents. The intelligent excavation system (IES) will improve the construction quality and productivity through information technologies and efficient equipment operation, especially in large earthwork projects. Three-dimensional digitized ground data should be required for identifying the path of heavy equipment and work-site environment. Rapid development of terrain laser scanners (TLS) is more readily to acquire the digital data. This study suggests the '3D ground terrain processing platform (3DGTPP)' including data manipulating module and analyzing module of the scanned data for intelligent earthmoving equipment operation. The processing platform consists of six modules, including scanning, registering, manipulating, analyzing, transmitting, and storing. 3D ground terrain processing platform presented in this study will provide fundamental information for intelligent excavation system (IES), which will increase the efficiency of earthworks and safety of workers in significant.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.2
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• pp.270-277
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• 2005

The purpose of this study was to clarify the palatal volume and anterior palatal slope of the children with class II div.1 malocclusion and normal occlusion in mixed dentition(Hellman dental age III A) using three-dimensional laser scanner. Samples were consisted of 31 children with skeletal class II div.1 malocclusion in mixed dentition and 29 children with normal occlusion and profile among the contestants in 2000-2004 Healthy Dentition Contest in Seoul. Totally 60 maxillary study model were taken. Each cast was scanned by three-dimensional laser scanner (Breuckmann opto-TOP HE, INUS, Korea) and shaped into the three-dimension image by Rapidform 2004 program(INUS, Korea). And the palatal volume and anterior palatal slope of each cast were calculated by Rapidform 2004 program(INUS, Korea). The values were statistically compared and evaluated by independent samples t-test with 95% of significance level. The results were as follows: 1. Palatal volume was significantly lesser in children with class II div.1 malocclusion than that of normal occlusion in mixed dentition(p<0.05). 2. No significant difference in the anterior palatal slope and palatal height was found between the children with class II div.1 malocclusion and normal occlusion in mixed dentition(p>0.05). 3. Palatal length was significantly greater in children with class II div.1 malocclusion than that of normal occlusion in mixed dentition(p<0.01). 4. Intercanine and intermolar width were significantly lesser in children with class II div.1 malocclusion than those of normal occlusion in mixed dentition(respectively p<0.05 and p<0.01).

• Korean Journal of Optics and Photonics
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• v.27 no.5
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• pp.165-173
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• 2016

In this paper, we propose a three-dimensional (3D) scanning system based on two line lasers. This system uses two line lasers with different wavelengths as light sources. 532-nm and 630-nm line lasers can compensate for missing scan data generated by geometrical occlusion. It also can classify two laser planes by using the red and green channels. For automatic registration of scanning data, we control a stepping motor and divide the motor's rotational degree of freedom into micro-steps. To this end, we design a control printed circuit board for the laser and stepping motor, and use an image processing board. To compute a 3D point cloud, we obtain 200 and 400 images with laser lines and segment lines on the images at different degrees of rotation. The segmented lines are thinned for one-to-one matching of an image pixel with a 3D point.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.31 no.2
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• pp.149-157
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• 2009

Purpose: This study was to evaluate the validity of superimposition range at facial images constructed with 3-dimensional (3D) surface laser scanning system. Materials and methods: For the present study, thirty adults, who had no severe skeletal discrepancy, were selected and scanned twice by a 3D laser scanner (VIVID 910, Minolta, Tokyo, Japan) with 12 markers placed on the face. Then, two 3D facial images (T1-baseline, T2-30 minutes later) were reconstructed respectably and superimposed in several manners with $RapidForm^{TM}2006$ (Inus, Seoul, Korea) software program. The distances between markers at the same place of face were measured in superimposed 3D facial images and measurement were done all the 12 makers respectably. Results: The average linear distances between the markers at the same place in the superimposed image constructed by upper 2/3 of the face was $0.92{\pm}0.23\;mm$, in the superimposed image constructed by upper 1/2 of the face was $0.98{\pm}0.26\;mm$, in the superimposed image constructed by upper 1/3 of the face and nose area was $0.99{\pm}0.24\;mm$, in the superimposed image constructed by upper 1/3 of the face was $1.41{\pm}0.48\;mm$, and in the superimposed image constructed by whole face was $0.83{\pm}0.13\;mm$. There were no statistically significant differences in the liner distances of the makers placed on the area included in superimposition range used for partial registration methods but there were significant differences in the linear distances of the markers placed on the areas not included in superimposition range between whole registration method and partial registration methods used in this study. Conclusion: The results of the present study suggest that the validity of superimposition is decreased as superimposition range is reduced in the superimposition of 3D images constructed with 3D laser scanner for the same subject.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.1
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• pp.132-142
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• 2003

This study is performed to investigate the characteristics of the palatal morphology of the children with anterior crossbite in Hellman dental age IIIA by 3-dimensional laser scanner. Totally 40 study casts were taken; 20 were from children with crossbite and another 20 were from normal occlusion as a control. Each cast was scanned by 3 dimension laser scanner and shaped by the 3 dimension image by rapidform 2000 program(INUS, Korea). And finally it was calculated by Rhino 3D program(Rhinoceros, USA). The intercanine, intermolar cross-sectioned transverse plane and sagittal plane were measured. Due to the variations in palatal morphology, each group was standardized into 25mm, 35mm, 35mm. By sectioning standardized curves of the Palatal morphology per 1mm, the palatal depth of each point was calculated. Through these complex methods, the mean curves of the palatal morphology could be obtained and the values were statistically compared and evaluated by T-test with 95% of significance level. The results were as follows: 1. In the intercanine cross-sectioned transverse plane, the mean curve of palatal morphology of crossbite group was flatter V shape than that of control group, however, there was no statistical significance was found between two groups(P>0.05). 2. In the intermolar cross-sectioned transverse plane, the mean curve of palatal morphology of crossbite was deeper all over the area than that of control group, and the statistical significance was found in the middle area from point 8 to 21(P<0.05). 3. In the sagittal plane, the mean curve of palatal morphology of crossbite group was more deepening as approaching posteriorly than that of control group, and the statistical significance was found in all over the area(P<0.01).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.10
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• pp.346-351
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• 2018

Metal three-dimensional (3D) printing technologies are mainly classified as powder bed fusion (PBF) and direct energy deposition (DED) methods according to the method of application of a laser beam to metallic powder. The DED method can be used to fabricate fine and hard 3D metallic structures by applying a strong laser beam to a thin layer of metallic powder. The PBF method involves slicing 3D graphics to be a certain height, laminating metal powders, and making a 3D structure using a laser. While the DED method has advantages such as laser cladding and metallic welding, it causes problems with low density when 3D shapes are created. The PBF method was introduced to address the structural density issues in the DED method and makes it easier to produce relatively dense 3D structures. In this paper, thin lines were produced by using PBF 3D printers with stainless-steel powder of roughly $30{\mu}m$ in diameter with a galvano scanner and fiber-transferred Nd:YAG laser beam. Experiments were carried out to find the optimal conditions for the width of a line depending on the processing times, laser power, spot size, and scan speed. The optimal conditions were two scanning processes in one line structure with a laser power of 30 W, spot size of $28.7{\mu}m$, and scan speed of 200 mm/s. With these conditions, a minimum width of about $85.3{\mu}m$ was obtained.

• Journal of Technologic Dentistry
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• v.45 no.1
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• pp.1-7
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• 2023

Purpose: To evaluate the marginal and internal fit of metal coping fabricated by a metal three-dimensional (3D) printer that uses selective laser melting (SLM). Methods: An extraoral scanner was used to scan a die of the prepared maxillary right first molar, and the coping was designed using computer-aided design software and saved as an stereo lithography (STL) file. Ten specimens were printed with an SLM-type metal 3D printer (SLM group), and 10 more specimens were fabricated by casting the castable patterns output generated by a digital light processing-type resin 3D printer (casting the 3D printed resin patterns [CRP] group). The fit was measured using the silicon replica technique, and 8 points (A to H) were set per specimen to measure the marginal (points A, H) and internal (points B~G) gaps. The differences among the groups were compared using the Mann-Whitney U-test (α=0.05). Results: The mean of marginal fit in the SLM group was 69.67±18.04 ㎛, while in the CRP group was 117.10±41.95 ㎛. The internal fit of the SLM group was 95.18±41.20 ㎛, and that of the CRP group was 86.35±32 ㎛. As a result of statistical analysis, there was a significant difference in marginal fit between the SLM and CRP groups (p<0.05); however, there was no significant difference in internal fit between the SLM group and the CRP group (p>0.05). Conclusion: The marginal and internal fit of SLM is within the clinically acceptable range, and it seems to be applicable in terms of fit.

• The Research Journal of the Costume Culture
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• v.10 no.6
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• pp.709-717
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• 2002

In the apparel industry, the technology has been advanced rapidly. The use of 3D scanning systems fur the capture and measurement of human body is becoming common place. Three dimensional digital image can be used for design, inspection, reproduction of physical objects. The purpose of this study is to develop a method that drafts men's basic bodice pattern from scanned 3D body surface shape data. In order to pursue this purpose the researchers developed pattern drafting algorithm. The 3D scanner used in this study was Cyberware Whole Body Scanner WB-4. The bodice pattern drafting algorithm from 3D body surface shape data developed in this study is as follows. First, convert geometric 3D body surface data to 3D polygonal mesh data. Second, develop algorithm to lay out 3D polygonal patches onto a plane using Auto Lisp program. The polygon meshes are coplanar, and the individual mesh is continuously in contact with next one The bodice front surface shape data in polygonal patches form was lined up in bust and waist levels. The back bodice was drafted by lining up the polygonal mesh in scapula, chest, and waist levels. in the drafts, gaps between polygons were formed into the darts.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.4
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• pp.643-652
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• 2006

The purpose of this study was to elucidate the size and morphologic characteristics of maxillary primary first molars in Korean children using three-dimensional laser scanner and compare three-dimensional image with preformed stainless steel crown. Scanned three-dimensional images of dental cast taken from 132 children(male 62, female 70) by three-dimensional laser scanner(Breuckmann opto-Top HE100, INUS, Korea) were used. Mesiodistal diameter, buccolingual diameter, occlusogingival height and crown shape of each image were calculated by Rapidform 2004 program(INUS, Korea). The values were statistically compared by independent samples t-test with 95% of significant level. The results were as follows : 1. No significant difference in crown size was found between left and right maxillay primary first molar(p>0.05). 2, Significant difference in mesiodistal diameter, buccolingual diameter, buccal occlusogingival height was found between male and female (p<0.05), and crown size of male was bigger than that of female. 3. Average image of maxillay primary first molar was shaped three-dimensionally and measured. In comparison with 3M stainless steel crown, this image was similar with No.4 or No.5 SS crown in male, No.4 in female. In comparison with ILSUNG SS crown, this image was similar with No.5 in male, No.4 in female. 4 Mesiolingual line angle area, distolingual line angle area and buccogingival ridge were more obvious in average image than 3M stainless steel crown. ILSUNG SS crown was more square and had longer mesiodistal diameter than average 3D image.