353 results on '"Sung-Hwan Choi"'
Search Results
152. Effects of recycling on the biomechanical characteristics of retrieved orthodontic miniscrews
- Author
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Soon Dong Yun, Chung Ju Hwang, Sung Hwan Choi, Kwang Mahn Kim, Jin Kim, Jung Yul Cha, and Hyung Seog Yu
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Orthodontics ,Insertion torque ,Artificial bone ,Biomechanical characteristics ,Materials science ,030206 dentistry ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Chemical cleaning ,Reader’s Forum ,03 medical and health sciences ,0302 clinical medicine ,medicine.anatomical_structure ,Insertion time ,medicine ,Cortical bone ,Original Article ,Recycling ,Surface characteristics ,Retrieved orthodontic miniscrew ,0210 nano-technology ,Bone volume - Abstract
OBJECTIVE The aim of this study was to compare recycled and unused orthodontic miniscrews to determine the feasibility of reuse. The comparisons included both miniscrews with machined surfaces (MS), and those with etched surfaces (ES). METHODS Retrieved MS and ES were further divided into three subgroups according to the assigned recycling procedure: group A, air-water spray; group B, mechanical cleaning; and group C, mechanical and chemical cleaning. Unused screws were used as controls. Scanning electron microscopy, energy-dispersive X-ray spectrometry, insertion time and maximum insertion torque measurements in artificial bone, and biological responses in the form of periotest values (PTV), bone-implant contact ratio (BIC), and bone volume ratio (BV) were assessed. RESULTS Morphological changes after recycling mainly occurred at the screw tip, and the cortical bone penetration success rate of recycled screws was lower than that of unused screws. Retrieved ES needed more thorough cleaning than retrieved MS to produce a surface composition similar to that of unused screws. There were no significant differences in PTV or BIC between recycled and unused screws, while the BV of the former was significantly lower than that of the latter (p < 0.05). CONCLUSIONS These results indicate that reuse of recycled orthodontic miniscrews may not be feasible from the biomechanical aspect.
- Published
- 2017
153. Occurrence of Weed Species on Turf Sod Production Areas in Jangsung-gun, Jeonnam Province
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Dong Woon Lee, Sung Hwan Choi, and Soo Jeong Ahn
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Cyperus iria ,Perennial plant ,ved/biology ,ved/biology.organism_classification_rank.species ,Erigeron annuus ,Biology ,Weed control ,biology.organism_classification ,Horticulture ,Agronomy ,Digitaria ciliaris ,Alopecurus aequalis ,Conyza canadensis ,Weed - Abstract
This study was conducted to provide basic information for weed control by surveying the occurrence of weed species in turf sod production areas. Surveys of weed species occurred in turf sod production areas were conducted in Jangsunggun, Jeonnam province from September 2014 to May 2016. Total 50 sites of turf sod production areas in two soil conditions were investigated. On the upland soil condition in turf sod production areas, 66 weed species in 27 families were identified and classified to 49 annuals and 17 perennials and on the paddy soil condition, 69 weed species in 22 families were identified and classified to 53 annuals and 16 perennials. Based on the importance values, the most dominant weed species on the upland soil condition in the first survey (September 2014) was Digitaria ciliaris (8.49%), followed by Erigeron annuus (7.94%) and Rorippa indica (6.56%). In the second survey (May 2016) was Oxalis corniculata (7.26%), followed by Capsella bursa-pastoris (6.21%) and Conyza canadensis (6.21%). Whereas the most dominant weed species on the paddy soil condition in the first survey (September 2014) was Erigeron annuus (9.52%), followed by Mazus pumilus (7.41%) and Cyperus iria (6.82%). In the second survey (May 2016) was Commelina communis (5.08%), followed by Alopecurus aequalis (5.08%) and Erigeron annuus (4.79%). This information could be useful for estimation of future weed occurrence and effective weed control methods in turf sod production areas in Jangsung-gun, Jeonnam Province.
- Published
- 2016
154. Is There a Difference in Stability After Intraoral Vertical Ramus Osteotomy Between Vertically High-Angle and Normal-Angle Patients?
- Author
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Chung Ju Hwang, Hyoung Seon Baik, Jung Yul Cha, Da Young Kang, Sung Hwan Choi, and Young-Soo Jung
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Adult ,Male ,Adolescent ,Cephalometry ,medicine.medical_treatment ,Osteotomy, Sagittal Split Ramus ,Dentistry ,Mandible ,Overbite ,Osteotomy ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,Recurrence ,medicine ,Humans ,Aged ,Retrospective Studies ,Aged, 80 and over ,Orthodontics ,business.industry ,Vertical Dimension ,Retrospective cohort study ,030206 dentistry ,Middle Aged ,Craniometry ,medicine.disease ,Malocclusion, Angle Class III ,Treatment Outcome ,Otorhinolaryngology ,Sample size determination ,030220 oncology & carcinogenesis ,Maxilla ,Female ,Surgery ,Oral Surgery ,Malocclusion ,business ,Follow-Up Studies - Abstract
Purpose Few studies have evaluated the relapse pattern of intraoral vertical ramus osteotomy (IVRO) for the correction of mandibular prognathism with a high angle. The aim of this study was to measure the association between vertical facial types (high and normal mandibular plane angle) and relapse after IVRO for the management of mandibular prognathism. Materials and Methods The retrospective cohort study sample (skeletal Class III patients) was divided into 2 groups according to the angle of the sella-nasion plane relative to the mandibular plane (SN-MP) at the initial examination. Lateral cephalograms were analyzed for the predictor (facial type) and outcome (cephalometric changes over time) variables before surgery, 7 days after surgery, and 12 months after surgery. The 2 groups were matched for sample size (n = 20 in each). Data were analyzed using repeated-measures analysis of variance with Bonferroni correction. Results The normal-angle group (group N, SN-MP from 27° to 37°) and high-angle group (group H, SN-MP >37°) were not significantly different in terms of gender and age at the initial examination. Seven days after surgery, the mandibles in group H moved 2.5 mm more superiorly than those in group N (P = .013); consequently, the amount of overbite correction in group H was approximately 2 mm greater than that in group N (P = .002). Nevertheless, 12 months after surgery, there was no statistically significant difference in relapse of the maxilla and mandible between the 2 groups. In the 2 groups, the mandible moved approximately 0.7 mm superiorly during retention. Conclusions These findings suggest that IVRO is a clinically acceptable and stable treatment modality for mandibular prognathism with a high angle.
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- 2016
155. Retrospective study of maxillary sinus dimensions and pneumatization in adult patients with an anterior open bite
- Author
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Kee Joon Lee, Jung Yul Cha, Chung Ju Hwang, Jesung Ryu, and Sung Hwan Choi
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Adult ,Male ,0301 basic medicine ,Cone beam computed tomography ,Adolescent ,Maxillary sinus ,Dentistry ,Orthodontics ,Mandibular first molar ,Young Adult ,03 medical and health sciences ,Basal (phylogenetics) ,0302 clinical medicine ,Occlusion ,Alveolar Process ,Premolar ,medicine ,Humans ,Retrospective Studies ,Open bite ,business.industry ,Open Bite ,Retrospective cohort study ,030206 dentistry ,Cone-Beam Computed Tomography ,Maxillary Sinus ,medicine.anatomical_structure ,Case-Control Studies ,Female ,030101 anatomy & morphology ,business - Abstract
The aim of this study was to evaluate differences in the maxillary sinus floor levels between adults with an anterior open bite and those without.This retrospective study included 30 subjects: 15 adults with an anterior open bite (mean age, 21.5 ± 4.3 years) and 15 control subjects with normal occlusion (mean age, 21.7 ± 3.1 years). Cone-beam computed tomography and lateral cephalograms were analyzed before treatment.The open-bite group exhibited a significantly greater maxillary posterior alveolar height (P 0.05). The craniocaudal heights of the maxillary sinus in the region between the first and second molars and between the second premolar and first molar were significantly greater in the open bite group (40.5 and 39.0 mm, respectively) than in the control group (36.7 and 34.7 mm, respectively; P 0.05 for both). The basal bone heights in the regions between the first and second molars, the second premolar and first molar, and the first and second premolars were significantly smaller in the open-bite group than in the control group (P 0.001 for all).Vertical pneumatization of the maxillary sinus floor in the region between the first and second molars and between the second premolar and first molar is greater in adults with an anterior open bite than in those without, whereas basal bone height in the maxillary posterior region is lower in the open-bite patients.
- Published
- 2016
156. Changes in the craniofacial complex and alveolar bone height of young adults: Applications to dental medicine
- Author
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Sung Hwan Choi, Si Nae Jung, Hyoung Seon Baik, Kyung Seok Hu, Jung Yul Cha, Kee-Deog Kim, and Chung Ju Hwang
- Subjects
0301 basic medicine ,Orthodontics ,Histology ,business.industry ,Radiography ,Dentistry ,Soft tissue ,030206 dentistry ,General Medicine ,Craniometry ,03 medical and health sciences ,0302 clinical medicine ,medicine.anatomical_structure ,medicine ,030101 anatomy & morphology ,Anatomy ,Young adult ,Craniofacial ,business ,Prospective cohort study ,Nose ,Dental alveolus - Abstract
The few studies on craniofacial complex changes in adults have reported contradictory findings. The aim of this study was to radiographically evaluate changes in the craniofacial complex and alveolar bone height of young adults over a 4-year period. This prospective study included 82 young adults (62 men; mean age, 19.0 ± 0.8 years; 20 women; mean age, 18.8 ± 0.9 years). Three radiographic examinations were performed longitudinally: the first (T0) was conducted at the start of the study, the second (T1) was conducted 2 years later, and the third (T2) was conducted at the end of the study period. As part of these examinations, lateral cephalograms, maxillary and mandibular anterior periapical radiographs, and bilateral posterior bitewing radiographs were obtained. During the 4-year follow-up period, all linear cephalometric measurements were significantly greater in men than in women. The amount of increase in the anterior facial height between T1 and T2 was lower in women than in men (P = 0.029). The rate of uprighting of the upper incisors was lower in men than in women over time (P = 0.020). The apex of the nose moved inferiorly between T0 and T2 (P = 0.006). The average overall change in the alveolar bone height was 0.27 mm and the yearly change was 0.07 mm over the 4-year period (P< 0.001). Significant changes in the skeletal, dental, and soft tissue, as well as, natural changes in alveolar bone, occur in young adults over time. Clin. Anat. 29:1011-1017, 2016. © 2016 Wiley Periodicals, Inc.
- Published
- 2016
157. The effects of alveolar bone loss and miniscrew position on initial tooth displacement during intrusion of the maxillary anterior teeth: Finite element analysis
- Author
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Sun Mi Cho, Hyung Seog Yu, Chung Ju Hwang, Sang Jin Sung, and Sung Hwan Choi
- Subjects
Orthodontics ,Bone loss ,business.industry ,Intrusion ,Finite element analysis ,Dentistry ,030206 dentistry ,Finite element method ,03 medical and health sciences ,stomatognathic diseases ,0302 clinical medicine ,stomatognathic system ,Miniscrew ,Maxillary central incisor ,Displacement (orthopedic surgery) ,Original Article ,030212 general & internal medicine ,business ,Anterior teeth ,Dental alveolus ,Geology - Abstract
Objective The aim of this study was to determine the optimal loading conditions for pure intrusion of the six maxillary anterior teeth with miniscrews according to alveolar bone loss. Methods A three-dimensional finite element model was created for a segment of the six anterior teeth, and the positions of the miniscrews and hooks were varied after setting the alveolar bone loss to 0, 2, or 4 mm. Under 100 g of intrusive force, initial displacement of the individual teeth in three directions and the degree of labial tilting were measured. Results The degree of labial tilting increased with reduced alveolar bone height under the same load. When a miniscrew was inserted between the two central incisors, the amounts of medial-lateral and anterior-posterior displacement of the central incisor were significantly greater than in the other conditions. When the miniscrews were inserted distally to the canines and an intrusion force was applied distal to the lateral incisors, the degree of labial tilting and the amounts of displacement of the six anterior teeth were the lowest, and the maximum von Mises stress was distributed evenly across all the teeth, regardless of the bone loss. Conclusions Initial tooth displacement similar to pure intrusion of the six maxillary anterior teeth was induced when miniscrews were inserted distal to the maxillary canines and an intrusion force was applied distal to the lateral incisors. In this condition, the maximum von Mises stresses were relatively evenly distributed across all the teeth, regardless of the bone loss.
- Published
- 2016
158. Similarity index for intuitive assessment of three-dimensional facial asymmetry
- Author
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Sung Hwan Choi, Sun Mi Kwon, Chung Ju Hwang, Jae Joon Hwang, Kee Joon Lee, Bong-Hae Cho, and Yun Hoa Jung
- Subjects
Adult ,Male ,0301 basic medicine ,Adolescent ,Cephalometry ,medicine.medical_treatment ,media_common.quotation_subject ,Orthognathic surgery ,lcsh:Medicine ,Mandible ,Asymmetry ,Article ,Young Adult ,03 medical and health sciences ,Imaging, Three-Dimensional ,0302 clinical medicine ,Similarity (network science) ,medicine ,Humans ,lcsh:Science ,media_common ,Mathematics ,Orthodontics ,Multidisciplinary ,Orthognathic Surgical Procedures ,lcsh:R ,Soft tissue ,Translational research ,medicine.disease ,Sagittal plane ,Malocclusion, Angle Class III ,Treatment Outcome ,030104 developmental biology ,medicine.anatomical_structure ,Facial Asymmetry ,Outcomes research ,Face ,Female ,lcsh:Q ,Malocclusion ,030217 neurology & neurosurgery ,Facial symmetry - Abstract
Evaluation of facial asymmetry generally involves landmark-based analyses that cannot intuitively assess differences in three-dimensional (3D) stereoscopic structures between deviation and non-deviation sides. This study tested a newly developed similarity index that uses a mirroring technique to intuitively evaluate 3D mandibular asymmetry, and characterised the resulting lower facial soft tissue asymmetry. The similarity index was used to evaluate asymmetry before and after surgery in 46 adult patients (27 men, 19 women; age, 22 ± 4.8 years) with skeletal Class III malocclusion and facial asymmetry who underwent conventional bimaxillary orthognathic surgery. Relative to the midsagittal plane used as the reference plane, the non-overlapping volume of the mandible significantly decreased, and the similarity index significantly increased after surgery. Similarity indexes of the mandible and lower facial soft tissue were strongly negatively correlated with non-overlapping volumes of each measurement. Differences in bilateral hemi-mandibular and hemi-lower facial soft tissue surface and volume measurements before surgery were significantly negatively correlated with similarity indexes of the mandible before and after surgery. This newly developed similarity index and non-overlapping volume using a mirroring technique can easily and intuitively evaluate overall 3D morphological discrepancies, especially 3D mandibular asymmetry, before and after surgery in skeletal Class III patients with facial asymmetry.
- Published
- 2019
159. Evaluation of success rate and biomechanical stability of ultraviolet-photofunctionalized miniscrews with short lengths
- Author
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Jung Yul Cha, Jiuk Shin, Jae-Sung Kwon, Jae Kook Cha, Sung Hwan Choi, and Chung Ju Hwang
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Orthodontics ,Male ,Titanium ,business.industry ,Ultraviolet Rays ,Bone Screws ,030206 dentistry ,Osseointegration ,Bone and Bones ,Bone screws ,03 medical and health sciences ,0302 clinical medicine ,Dogs ,Torque ,Ultraviolet light ,Orthodontic Anchorage Procedures ,Medicine ,Animals ,business ,030217 neurology & neurosurgery - Abstract
The aim of this research was to verify that ultraviolet light (UV)-photofunctionalization improves the success rate and biomechanical stability of miniscrews regardless of length, and to evaluate the comparability of biomechanical stability between UV-photofunctionalized miniscrews with short lengths and untreated miniscrews with conventional lengths.Eight male beagles (age, 12-15 months; weight, 10-13 kg) received a total of 64 miniscrews, including 7-mm and 4-mm untreated and UV-photofunctionalized, acid-etched miniscrews with the use of a random block design. The cumulative success rates were examined in all studied groups. The insertion and removal torques and screw mobility were measured. Microcomputed tomographic scans and histomorphometric analyses were performed at 8 weeks postoperatively.The success rates of 7-mm UV-untreated and UV-photofunctionalized miniscrews were 87.5% and 100%, respectively, vs 43.8% for the 4-mm UV-untreated and 4-mm UV-photofunctionalized miniscrews. The rates were significantly different in accordance with the length (P 0.001). There were no differences in the insertion and removal torque and screw mobility between groups according to the length or UV treatment. However, the 4-mm UV-untreated miniscrews yielded a mean bone area ratio of 6.35 ± 7.43%, whereas the 7-mm UV-photofunctionalized miniscrew yielded a mean ratio of 32.17 ± 8.34% (P = 0.037).The UV-photofunctionalization significantly increased the biomechanical stability and led to increased bone and miniscrew contact area in dogs with miniscrews of the same length. However, the most important factor that affected the success rate of the miniscrew was the length.
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- 2019
160. Effect of Litter Quality on Needle Decomposition for Four Pine Species in Korea
- Author
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SangHoon Lee, Jae Kuk Shim, Sangsub Cha, Sung Hwan Choi, Keum Chul Yang, and Hee Myung Chae
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0106 biological sciences ,Litter (animal) ,biology ,Specific leaf area ,Pinus koraiensis ,Chemistry ,conifer ,Forestry ,lcsh:QK900-989 ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Pinus rigida ,Decomposition ,microcosm ,Horticulture ,Pinus thunbergii ,Pinus densiflora ,lcsh:Plant ecology ,physiochemical litter quality ,Microcosm ,Pinus ,needle litter decomposition ,010606 plant biology & botany - Abstract
Litter decomposition involves multiple complex processes, including interactions between the physicochemical characteristics of litter species and various environmental factors. We selected four representative pine species in South Korea (Pinus densiflora Siebold &, Zucc., Pinus thunbergii Parl., Pinus koraiensis Siebold &, Zucc., and Pinus rigida Miller) to investigate the decay rate and effects of the physicochemical properties on decomposition. Needle litters were incubated in microcosms at 23 °, C for 280 days and retrieved four times in about 70-day intervals. The mass loss showed significant differences among the species and was higher in the order of P. densiflora (30.5%), P. koraiensis (27.8%), P. rigida (26.5%), and P. thunbergii (23.6%). The needle litter decomposition showed a negative relationship with the initial surface area, volume, density, cellulose content, and lignin/nitrogen of the litter, and a positive relationship with the initial specific leaf area (SLA), surface-area-to-volume ratio (SA/V), and water- and ethanol-soluble substances. The decomposition rate was highly affected by the physical properties of litter when compared with the initial chemical litter quality, and it was strongly influenced by SLA and SA/V. Accordingly, the physical properties of pine needle litter, especially SLA and SA/V, may be the key factors, and they could be used as predictive indices for the decomposition rate of pine tree litters.
- Published
- 2019
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161. Novel anti-biofouling light-curable fluoride varnish containing 2-methacryloyloxyethyl phosphorylcholine to prevent enamel demineralization
- Author
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Sungil Jang, Sung Hwan Choi, Chung Ju Hwang, Jae-Sung Kwon, Ji-Young Kim, Jeong Hyun Ryu, Kwang Mahn Kim, Myung-Jin Lee, and Dohyun Kim
- Subjects
0301 basic medicine ,Phosphorylcholine ,Science ,Bacterial Adhesion ,Article ,Streptococcus mutans ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,immune system diseases ,medicine ,Actinomyces ,Animals ,Fluorides, Topical ,Bovine serum albumin ,Dental Enamel ,Tooth Demineralization ,Multidisciplinary ,biology ,Fluoride varnish ,biology.organism_classification ,Tooth enamel ,Cariostatic Agents ,Anti-Bacterial Agents ,Demineralization ,Streptococcus sanguinis ,030104 developmental biology ,medicine.anatomical_structure ,chemistry ,Actinomyces naeslundii ,biology.protein ,Methacrylates ,Medicine ,Cattle ,Fluoride ,030217 neurology & neurosurgery ,Nuclear chemistry - Abstract
We evaluated the efficacy of light-curable fluoride varnish (LCFV) that contains 2-methacryloyloxyethyl phosphorylcholine (MPC) in terms of anti-biofouling properties and prevention of tooth enamel demineralization. MPC was mixed with and incorporated into LCFV at 0 (control), 1.5, 3.0, 5.0, 10.0, 20.0, and 40.0 weight percentage (wt%). Addition of high wt% of MPC resulted in increased film thickness and decreased the degree of conversion, indicating loss of the advantageous properties of LCFV. Addition of 1.5, 3, or 5 wt% MPC significantly reduced the amount of bovine serum albumin adsorbed from a solution and proteins adsorbed from brain heart infusion medium compared to the control (P Streptococcus mutans cells adhered on the surface of LCFV with 1.5, 3, or 5 wt% MPC (P Actinomyces naeslundii and Streptococcus sanguinis adherence to LCFV with 3 wt% MPC. Finally, bacterial adhesion, surface microhardness loss, and the depth of demineralization were substantially lower on bovine tooth enamel surface coated with LCFV containing 3 wt% of MPC than in the control treatment (0 wt% MPC). Therefore, this novel LCFV containing a low concentration of MPC (e.g., 3 wt%) would be effective in anti-biofouling while maintaining the important advantageous features of light-curable fluoride in preventing demineralization.
- Published
- 2019
162. Differences in soft-tissue thickness changes after bimaxillary surgery between patients with vertically high angle and normal angle
- Author
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Hwi-Dong Jung, Sung Hwan Choi, Chung Ju Hwang, Hyemin Lee, Jae Joon Hwang, and Jung Yul Cha
- Subjects
Adult ,Male ,medicine.medical_specialty ,Adolescent ,Cephalometry ,Orthodontics ,Mandible ,03 medical and health sciences ,Young Adult ,0302 clinical medicine ,Maxilla ,Medicine ,Humans ,High angle ,In patient ,business.industry ,Soft tissue ,030206 dentistry ,Skeletal class ,medicine.disease ,Surgery ,Mandibular prognathism ,Linear relationship ,Malocclusion, Angle Class III ,Face ,Multiple linear regression analysis ,Female ,Malocclusion ,business ,030217 neurology & neurosurgery - Abstract
Introduction We evaluated soft-tissue thickness changes after bimaxillary surgery according to vertical facial patterns in patients with skeletal Class III malocclusion with mandibular prognathism. Methods Forty-three Korean patients (16 men and 27 women; mean age, 22.6 ± 4.1 years) with skeletal Class III malocclusion who underwent bimaxillary surgery were divided into 2 groups: normal-angle group (N group) and high-angle group (H group), on the basis of the presurgical angle of the mandibular plane relative to the sella-nasion plane (SN-MP). Changes in hard-tissue landmarks and soft-tissue thickness before and after surgery were analyzed from reconstructed 3-dimensional cone-beam computed tomography images. Postoperative soft-tissue thickness in both groups was compared with that in 40 patients with normal skeletal Class I malocclusion in the reference group. Results Group N (27°-37°) and group H (>37°) did not differ significantly in terms of sex and age before surgery. Preoperative pogonion (Pog) thickness was significantly less in group H (9.7 ± 1.6 mm) than in group N (10.8 ± 1.9 mm) (P = 0.042). Adjusted multiple linear regression analysis showed a weak positive linear relationship between the SN-MP before surgery and soft-tissue Pog thickness change (R2 of 0.361; P = 0.001) after surgery, but the area below the lower lips was not completely normalized despite surgery. Conclusions The thickness of the soft-tissue Pog may increase slightly after surgery in patients with skeletal Class III malocclusion with a higher preoperative mandibular plane angle, but normalization in the area cannot be completely achieved despite surgery.
- Published
- 2019
163. Durable Oral Biofilm Resistance of 3D-Printed Dental Base Polymers Containing Zwitterionic Materials
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Myung-Jin Lee, Jae-Sung Kwon, Jie Jin, Sung Hwan Choi, Ji Yeong Kim, Utkarsh Mangal, Ji-Young Seo, and Jaehun Yu
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3d printed ,Materials science ,Polymers ,Phosphorylcholine ,zwitterion ,Biocompatible Materials ,02 engineering and technology ,Methacrylate ,Composite Resins ,Bacterial Adhesion ,Article ,Catalysis ,Streptococcus mutans ,lcsh:Chemistry ,Inorganic Chemistry ,Dental Materials ,03 medical and health sciences ,0302 clinical medicine ,Materials Testing ,Humans ,Microbial colonization ,Physical and Theoretical Chemistry ,lcsh:QH301-705.5 ,Molecular Biology ,Spectroscopy ,dental base resin ,chemistry.chemical_classification ,Mouth ,oral salivary biofilm ,dentistry ,Organic Chemistry ,Biofilm ,3D printing ,030206 dentistry ,General Medicine ,Polymer ,021001 nanoscience & nanotechnology ,Computer Science Applications ,lcsh:Biology (General) ,lcsh:QD1-999 ,chemistry ,Chemical engineering ,Biofilms ,Printing, Three-Dimensional ,Methacrylates ,durability ,0210 nano-technology ,poly(methyl methacralyate) ,Dental Base - Abstract
Poly(methyl methacralyate) (PMMA) has long been used in dentistry as a base polymer for dentures, and it is recently being used for the 3D printing of dental materials. Despite its many advantages, its susceptibility to microbial colonization remains to be overcome. In this study, the interface between 3D-printed PMMA specimens and oral salivary biofilm was studied following the addition of zwitterionic materials, 2-methacryloyloxyethyl phosphorylcholine (MPC) or sulfobetaine methacrylate (SB). A significant reduction in bacterial and biofilm adhesions was observed following the addition of MPC or SB, owing to their protein-repellent properties, and there were no significant differences between the two test materials. Although the mechanical properties of the tested materials were degraded, the statistical value of the reduction was minimal and all the properties fulfilled the requirements set by the International Standard, ISO 20795-2. Additionally, both the test materials maintained their resistance to biofilm when subjected to hydrothermal fatigue, with no further deterioration of the mechanical properties. Thus, novel 3D-printable PMMA incorporated with MPC or SB shows durable oral salivary biofilm resistance with maintenance of the physical and mechanical properties.
- Published
- 2021
164. Primary Stability of Orthodontic Titanium Miniscrews due to Cortical Bone Density and Re-Insertion
- Author
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Kwang Mahn Kim, Kee Joon Lee, Jie Jin, Gi Tae Kim, Sung Hwan Choi, Utkarsh Mangal, and Jae-Sung Kwon
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primary stability ,Insertion torque ,Artificial bone ,Materials science ,medicine.medical_treatment ,Removal torque ,micromotion ,chemistry.chemical_element ,02 engineering and technology ,lcsh:Technology ,Article ,Abrasion (geology) ,03 medical and health sciences ,0302 clinical medicine ,medicine ,General Materials Science ,lcsh:Microscopy ,Reduction (orthopedic surgery) ,lcsh:QC120-168.85 ,Pound (force) ,lcsh:QH201-278.5 ,lcsh:T ,horizontal resistance ,retrieved miniscrew ,030206 dentistry ,021001 nanoscience & nanotechnology ,medicine.anatomical_structure ,chemistry ,lcsh:TA1-2040 ,cortical bone density ,re-insertion ,lcsh:Descriptive and experimental mechanics ,Cortical bone ,lcsh:Electrical engineering. Electronics. Nuclear engineering ,lcsh:Engineering (General). Civil engineering (General) ,0210 nano-technology ,lcsh:TK1-9971 ,Titanium ,Biomedical engineering - Abstract
The increasing demand for orthodontic treatment over recent years has led to a growing need for the retrieval and reuse of titanium-based miniscrews to reduce the cost of treatment, especially in patients with early treatment failure due to insufficient primary stability. This in vitro study aimed to evaluate differences in the primary stability between initially inserted and re-inserted miniscrews within different cortical bone densities. Artificial bone was used to simulate cortical bone of different densities, namely 20, 30, 40, and 50 pound per cubic foot (pcf), where primary stability was evaluated based on maximum insertion torque (MIT), maximum removal torque (MRT), horizontal resistance, and micromotion. Scanning electron microscopy was used to evaluate morphological changes in the retrieved miniscrews. The MIT, MRT, horizontal resistance, and micromotion was better in samples with higher cortical bone density, thereby indicating better primary stability (P <, 0.05). Furthermore, a significant reduction of MIT, MRT, and horizontal resistance was observed during re-insertion compared with the initial insertion, especially in the higher density cortical bone groups. However, there was no significant change in micromotion. While higher cortical bone density led to better primary stability, it also caused more abrasion to the miniscrews, thereby decreasing the primary stability during re-insertion.
- Published
- 2020
165. Stress distributions in peri-miniscrew areas from cylindrical and tapered miniscrews inserted at different angles
- Author
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Youn Sic Chun, Sung Hwan Choi, Sang Jin Sung, Seong Jin Kim, Kee Joon Lee, and Chung Ju Hwang
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Orthodontics ,Materials science ,Insertion angle ,business.industry ,Miniscrew design ,Orthodontic miniscrews ,Finite element analysis ,Dentistry ,030206 dentistry ,Stress ,Finite element method ,Stress (mechanics) ,03 medical and health sciences ,0302 clinical medicine ,medicine.anatomical_structure ,medicine ,Perpendicular ,von Mises yield criterion ,Cortical bone ,Original Article ,030212 general & internal medicine ,business ,Cancellous bone ,Bone surface - Abstract
Objective: The purpose of this study was to analyze stress distributions in the roots, periodontal ligaments (PDLs), and bones around cylindrical and tapered miniscrews inserted at different angles using a finite element analysis. Methods: We created a three-dimensional (3D) maxilla model of a dentition with extracted first premolars and used 2 types of miniscrews (tapered and cylindrical) with 1.45-mm diameters and 8-mm lengths. The miniscrews were inserted at 30°, 60°, and 90° angles with respect to the bone surface. A simulated horizontal orthodontic force of 2 N was applied to the miniscrew heads. Then, the stress distributions, magnitudes during miniscrew placement, and force applications were analyzed with a 3D finite element analysis. Results: Stresses were primarily absorbed by cortical bone. Moreover, very little stress was transmitted to the roots, PDLs, and cancellous bone. During cylindrical miniscrew insertion, the maximum von Mises stress increased as insertion angle decreased. Tapered miniscrews exhibited greater maximum von Mises stress than cylindrical miniscrews. During force application, maximum von Mises stresses increased in both groups as insertion angles decreased. Conclusions: For both cylindrical and tapered miniscrew designs, placement as perpendicular to the bone surface as possible is recommended to reduce stress in the surrounding bone.
- Published
- 2016
166. Subjective food intake ability related to oral health-related quality of life and psychological health
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Kee Joon Lee, Sung Hwan Choi, Chung Ju Hwang, J.-S. Kim, Hyung Seog Yu, and Jung Yul Cha
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Adult ,Male ,Gerontology ,Adolescent ,Anxiety ,Models, Psychological ,Eating ,Food Preferences ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,Quality of life ,Surveys and Questionnaires ,Adaptation, Psychological ,Republic of Korea ,medicine ,Humans ,Young adult ,General Dentistry ,Reference group ,Depression (differential diagnoses) ,030206 dentistry ,Odds ratio ,Middle Aged ,Mental health ,Self Concept ,Confidence interval ,Food ,Quality of Life ,Mastication ,Female ,Self Report ,medicine.symptom ,Psychology ,030217 neurology & neurosurgery - Abstract
Reduced food intake ability can restrict an individual's choice of foods and might have a significant impact on the individual's quality of life and mental health. The aim of this study was to evaluate the correlations between self-reported masticatory ability and oral health-related quality of life (OHRQOL) and psychological health. The study included 72 (26 men, 46 women) adults with a mean age of 26·4 ± 8·6 years. Each participant completed the key subjective food intake ability (KFIA) test for five key foods, the Korean version of the Oral Health Impact Profile-14 (OHIP-14K) and three questionnaires for measuring anxiety, depression and self-esteem. The participants were distributed into two groups by sex (a mean age of 23·9 ± 5·2 for men and 27·9 ± 9·8 for women) and by the median KFIA score. There were no significant differences in any of the variables according to sex. Thirty-two participants (12 men, 20 women) in the lower KFIA group had a higher total OHIP-14K (P < 0·001) and depression level (P < 0·05) than the 40 participants (14 men, 26 women) in the higher KFIA group. As the KFIA decreased, OHRQOL worsened (P < 0·001) and depression increased (P < 0·05). Participants with lower KFIA scores were more than 4·3 times as likely as to have a poor OHRQOL than the reference group (odds ratio, 4·348; 95% confidence interval, 1·554-12·170, P < 0·01). Lower subjective food intake ability is associated with a poor oral health-related quality of life and higher depression level.
- Published
- 2016
167. Nonsurgical miniscrew-assisted rapid maxillary expansion results in acceptable stability in young adults
- Author
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Kyung Keun Shi, Young Chel Park, Kee Joon Lee, Sung Hwan Choi, and Jung Yul Cha
- Subjects
Adult ,Palatal Expansion Technique ,Adolescent ,Adult patients ,Cephalometry ,business.industry ,Transverse maxillary deficiency ,Dentistry ,Orthodontics ,Mean age ,Original Articles ,030206 dentistry ,Molar ,Young Adult ,03 medical and health sciences ,Dental Arch ,0302 clinical medicine ,Suture (anatomy) ,Maxilla ,Humans ,Medicine ,Rapid maxillary expansion ,Young adult ,business ,030217 neurology & neurosurgery - Abstract
Objective: To evaluate the stability of nonsurgical miniscrew-assisted rapid maxillary expansion (MARME) in young adults with a transverse maxillary deficiency. Materials and Methods: From a total of 69 adult patients who underwent MARME followed by orthodontic treatment with a straight-wire appliance, 20 patients (mean age, 20.9 ± 2.9 years) with follow-up records (mean, 30.2 ± 13.2 months) after debonding were selected. Posteroanterior cephalometric records and dental casts were obtained at the initial examination (T0), immediately after MARME removal (T1), immediately after debonding (T2), and at posttreatment follow-up (T3). Results: Suture separation was observed in 86.96% of subjects (60/69). An increase in the maxillary width (J-J; 1.92 mm) accounted for 43.34% of the total expansion with regard to the intermolar width (IMW) increase (4.43 mm; P < .001) at T2. The amounts of J-J and IMW posttreatment changes were −0.07 mm (P > .05) and −0.42 mm (P = .01), respectively, during retention. The postexpansion change in middle alveolus width increased with age (P < .05). The postexpansion change of interpremolar width (IPMW) was positively correlated with the amount of IPMW expansion (P < .05) but not with IMW. The changes of the clinical crown heights in the maxillary canines, first premolars, and first molars were not significant at each time point. Conclusions: Nonsurgical MARME can be a clinically acceptable and stable treatment modality for young adults with a transverse maxillary deficiency.
- Published
- 2016
168. The influence of age on lip-line cant in adults: a cross-sectional study
- Author
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Jung Suk Kim, Sung Hwan Choi, Cheol Soon Kim, and Chung Ju Hwang
- Subjects
medicine.medical_specialty ,business.industry ,Cross-sectional study ,Lip-line cant ,Orthodontics ,Retrospective cohort study ,030206 dentistry ,Predictor variables ,030230 surgery ,Cant (architecture) ,Surgery ,Menton deviation ,03 medical and health sciences ,stomatognathic diseases ,0302 clinical medicine ,Age ,Younger adults ,Medicine ,Adults ,Multiple linear regression analysis ,Original Article ,business ,Demography ,Lower degree - Abstract
Objective: The aims of this study were to assess the direction and degree of lip-line cant in Korean adult orthodontic patients and to identify the effects of sex and age on changes in the cant severity. Methods: In this cross-sectional retrospective study, lip-line cant was measured in the frontal photographs of 585 Korean patients (92 men and 493 women) aged 18−48 years. The outcome variables (direction and degree of lip-line cant) were assessed in terms of predictor variables (sex, age, sagittal skeletal relationship, and menton deviation angle). Results: The direction of lip-line cant did not differ according to sex, age, or skeletal classification. Patients had 1.6 o of lip-line cant on average before orthodontic treatment. Middle-aged adults displayed a significant trend toward a lower degree of lip-line cant compared to younger adults (p < 0.01). Multiple linear regression analysis showed that the degree of lip-line cant was weakly negatively correlated with age (p < 0.001). Conclusions: While the direction of lip-line cant did not differ according to the parameters explored here, the degree of cant was correlated with age in adults, independent of menton deviation. Specifically, middle-aged adults tended to display significantly lower degrees of lip-line cant than did younger adults. [Korean J Orthod 2016;46(2):81-86]
- Published
- 2016
169. Stability of Pre-Orthodontic Orthognathic Surgery Using Intraoral Vertical Ramus Osteotomy Versus Conventional Treatment
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Chung Ju Hwang, Kee Joon Lee, Sung Hwan Choi, Young-Soo Jung, and Hyoung Seon Baik
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Adult ,Male ,Adolescent ,Tooth Movement Techniques ,Cephalometry ,medicine.medical_treatment ,Bone Screws ,Mandibular Osteotomy ,Orthognathic surgery ,Dentistry ,Mandible ,Osteotomy ,Cohort Studies ,Young Adult ,03 medical and health sciences ,Orthognathic Surgical Procedures ,0302 clinical medicine ,Absorbable Implants ,Bone plate ,Maxilla ,medicine ,Humans ,Osteotomy, Le Fort ,Prognathism ,Retrospective Studies ,Orthodontics ,business.industry ,Vertical Dimension ,030206 dentistry ,Craniometry ,medicine.disease ,Jaw Fixation Techniques ,Malocclusion, Angle Class III ,Treatment Outcome ,Otorhinolaryngology ,030220 oncology & carcinogenesis ,Female ,Surgery ,Oral Surgery ,Malocclusion ,business ,Bone Plates ,Follow-Up Studies - Abstract
Postoperative skeletal and dental changes were evaluated in patients with mandibular prognathism who underwent mandibular setback surgery using an intraoral vertical ramus osteotomy (IVRO) with and without presurgical orthodontic treatment.This retrospective cohort study included consecutive patients with skeletal Class III malocclusions who underwent IVRO. Patients treated with pre-orthodontic orthognathic surgery (POGS) were compared with patients treated with conventional surgery (CS) with presurgical orthodontics (control) using lateral cephalograms (taken preoperatively, 7 days postoperatively, and 12 months postoperatively). Predictor (group and timing), outcome (cephalometric measurements over time), and other (ie, baseline characteristics) variables were evaluated to determine the differences in postoperative horizontal and vertical positional changes of the mandible, such as point B. Baseline demographics were similar between the groups (N = 37; CS group, n = 17; POGS group, n = 20). The data were analyzed with an independent t test, the Mann-Whitney U test, the Fisher exact t test, Pearson correlation analysis, and simple linear regression analysis.The mean setback of the mandible at point B was similar, but the mandible of the POGS group, particularly the distal segment, moved superiorly during the postoperative period in conjunction with the removal of premature occlusal contacts (P.001). In the CS group, the mandible had significantly more backward movement 12 months after surgery compared with the POGS group (P.01). In the POGS group, horizontal and vertical postsurgical changes were linearly correlated with the amount of setback and vertical movement of the mandible.Mandibular setback surgery using IVRO without presurgical orthodontics leads to considerably different postoperative skeletal and dental changes compared with conventional treatment, with more superior movement being observed at point B during the 1-year postoperative period.
- Published
- 2016
170. Evaluation of the surface characteristics of anodic oxidized miniscrews and their impact on biomechanical stability: An experimental study in beagle dogs
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Jung Yul Cha, Sung Ho Jang, Sung Hwan Choi, and Chung Ju Hwang
- Subjects
Male ,Materials science ,Surface Properties ,Scanning electron microscope ,Bone Screws ,chemistry.chemical_element ,Dentistry ,Orthodontics ,Mandible ,02 engineering and technology ,Surface finish ,Microscopy, Atomic Force ,Beagle ,Random Allocation ,03 medical and health sciences ,Dogs ,0302 clinical medicine ,Nickel ,Bone-Implant Interface ,Materials Testing ,Microscopy ,Alloys ,Orthodontic Anchorage Procedures ,Orthodontic Wires ,Surface roughness ,Animals ,Orthodontic Appliance Design ,Titanium ,Miniaturization ,business.industry ,Electrochemical Techniques ,Organ Size ,030206 dentistry ,021001 nanoscience & nanotechnology ,Biomechanical Phenomena ,Anode ,Machined surface ,Torque ,chemistry ,Microscopy, Electron, Scanning ,Stress, Mechanical ,0210 nano-technology ,business ,Oxidation-Reduction ,Dental Alloys ,Biomedical engineering - Abstract
In this study, we aimed to assess the surface characteristics and the biomechanical stability of miniscrews with an anodic oxidized surface compared with machined surface miniscrews in beagle dogs.Self-drilled, titanium-aluminum-vanadium alloy miniscrews with an anodic oxidized surface (n = 48) or a machined surface (n = 48) were placed into the mandibles of 12 beagle dogs. The surface characteristics of both types of miniscrews were analyzed before implantation with scanning electron microscopy and atomic force microscopy. Insertion torque was measured during placement of all 96 miniscrews. Half of the implants in each group (24 specimens per subgroup) received 200 to 250 g of tensile force for 3-week or 12-week loading periods. Removal torque was measured in 12 specimens of each subgroup, and bone-implant contact and bone volume were quantified in the other 12 specimens of each subgroup.Atomic force microscopy measurements demonstrated that the anodic oxidized surface miniscrews had significantly higher roughness parameters than did the machined surface miniscrews (P 0.001). The 2 types of miniscrews were not significantly different in insertion and removal torque values or in bone-implant contacts and bone volumes, regardless of the loading period.Anodic oxidized miniscrews have different surface roughness profiles but no clinically significant superiority in biomechanical stability compared with machined surface miniscrews.
- Published
- 2016
171. Evaluation of horticultural traits and genetic relationship in melon germplasm
- Author
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Juyeol Oh, Daeun Kim, Jaemin Jung, Young-Hoon Park, Beung-Gu Son, Sung-Hwan Choi, and Nahui Kim
- Subjects
Germplasm ,Melon ,UPGMA ,food and beverages ,Genetic relationship ,Plant Science ,Biology ,biology.organism_classification ,Agronomy ,Genetic distance ,Mantel test ,Cultivar ,Agronomy and Crop Science ,Cucumis ,Biotechnology - Abstract
Horticultural traits and genetic relationship were evaluated for 83 melon (Cucumis melo L.) cultivars. Survey of a total of 36 characteristics for seedling, leaf, stem, flower, fruit, and seed and subsequent multiple analysis of variance (MANOVA) were conducted. Principal component analysis (PCA) showed that 8 principle components including fruit weight, fruit length, fruit diameter, cotyledon length, seed diameter, and seed length accounted for 76.3% of the total variance. Cluster analysis of the 83 melon cultivars using average linkage method resulted in 5 clusters at coefficient of 0.7. Cluster I consisted of cultivars with high values for fruit-related traits, Cluster II for soluble solid content, and Cluster V for high ripening rate. Genotyping of the 83 cultivars was conducted using 15 expressed-sequence tagged-simple sequence repeat (EST-SSR) from the Cucurbit Genomics Initiative (ICuGI) database. Analysis of genetic relatedness by UPGMA resulted in 6 clusters. Mantel test indicated that correlation between morphological and genetic distance was very low (r = -0.11).
- Published
- 2015
172. The study of Influences of Physical Environment of Choir Performance Services on Quality of Interaction, Quality of Outcome and Behavioral Intention
- Author
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Sung-Hwan Choi, Yeong-ae Ku, and Eun-Ja Koo
- Subjects
Service (business) ,Value (ethics) ,Engineering ,Service quality ,business.industry ,media_common.quotation_subject ,Outcome (game theory) ,Order (business) ,Quality (business) ,Performing arts ,Marketing ,business ,Social psychology ,Tertiary sector of the economy ,media_common - Abstract
A cultural and art performance is a domain of the service from which consumers want to get a value through the experience, and a comprehensive study of the service quality the consumers judge to be important is necessary. Also, there are active studies of service quality in various service industries and fields, but there are not many studies related to service quality in the performance business. In the performance industry, the service quality of the theater has a great influence in order to express the distinct theme, and yet, there has been no study of theinfluences of the choice factors of performing arts, the quality of the physical environment, in other words, the qualityof interaction and the quality of the outcome of their selection of a performance of each type of use by the audienceof performing arts. Thus, this study aims to understand the quality of physical environment considered by the audience of a choir performance in the selection of the performance according to the type of use of the choir performanceand analyze the influences of these factors on the quality of interaction, the quality of outcome and behavioral intention to provide suggestions for the establishment of marketing strategies in the future.
- Published
- 2015
173. Effect of Audiovisual Treatment Information on Relieving Anxiety in Patients Undergoing Impacted Mandibular Third Molar Removal
- Author
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Chung Ju Hwang, Jung Yul Cha, Ji Hoon Won, and Sung Hwan Choi
- Subjects
Adult ,Male ,Dentistry ,Mandible ,Anxiety ,Trismus ,Audiovisual Aids ,law.invention ,Young Adult ,Randomized controlled trial ,law ,Informed consent ,medicine ,Humans ,Local anesthesia ,Prospective Studies ,Young adult ,Prospective cohort study ,business.industry ,Tooth, Impacted ,Otorhinolaryngology ,Tooth Extraction ,Female ,Surgery ,Oral Surgery ,medicine.symptom ,business - Abstract
The authors hypothesized that an audiovisual slide presentation that provided treatment information regarding the removal of an impacted mandibular third molar could improve patient knowledge of postoperative complications and decrease anxiety in young adults before and after surgery. A group that received an audiovisual description was compared with a group that received the conventional written description of the procedure.This randomized clinical trial included young adult patients who required surgical removal of an impacted mandibular third molar and fulfilled the predetermined criteria. The predictor variable was the presentation of an audiovisual slideshow. The audiovisual informed group provided informed consent after viewing an audiovisual slideshow. The control group provided informed consent after reading a written description of the procedure. The outcome variables were the State-Trait Anxiety Inventory, the Dental Anxiety Scale, a self-reported anxiety questionnaire, completed immediately before and 1 week after surgery, and a postoperative questionnaire about the level of understanding of potential postoperative complications. The data were analyzed with χ(2) tests, independent t tests, Mann-Whitney U tests, and Spearman rank correlation coefficients.Fifty-one patients fulfilled the inclusion criteria. The audiovisual informed group was comprised of 20 men and 5 women; the written informed group was comprised of 21 men and 5 women. The audiovisual informed group remembered significantly more information than the control group about a potential allergic reaction to local anesthesia or medication and potential trismus (P.05). The audiovisual informed group had lower self-reported anxiety scores than the control group 1 week after surgery (P .05).These results suggested that informing patients of the treatment with an audiovisual slide presentation could improve patient knowledge about postoperative complications and aid in alleviating anxiety after the surgical removal of an impacted mandibular third molar.
- Published
- 2015
174. Clinical applications of miniscrews that broaden the scope of non-surgical orthodontic treatment.
- Author
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Sung-Hwan Choi, Ji Yoon Jeon, Kee-Joon Lee, and Chung-Ju Hwang
- Subjects
ORTHOGNATHIC surgery ,MAXILLARY expansion ,CORRECTIVE orthodontics ,DENTAL arch ,TEETH ,MAXILLA ,MANDIBLE - Abstract
Previously, in the case of malocclusion owing to skeletal discrepancy in adults, the amount of tooth movement was limited since there was no reliable skeletal anchorage device. The only way to treat this case was by repositioning the maxilla and mandible via orthognathic surgery, but most patients are reluctant to undergo surgery owing to the risk and expenses incurred. However, with the current introduction and use of miniscrews as temporary anchorage devices, the entire dental arch can be relocated to a target position without surgery, thus broadening the scope of non-surgical orthodontic treatment compared to the past. For a non-surgical approach to improve skeletal discrepancy, anteroposterior, vertical and transverse displacements of the dental arch are necessary. In this case, the localization of the centre of resistance of the whole arch must precede the appliance design with an appropriate biomechanical design. Especially, in the transverse dimension, the envelope of discrepancy is reportedly narrow, and the tooth movement must accompany the orthopaedic correction involving the midpalatal suture expansion. Recently, in adults with transverse maxillomandibular discrepancy, miniscrew-assisted rapid palatal expansion (MARPE) can be performed. Moreover, compared to surgically assisted rapid palatal expansion, MARPE reduces the cost to the patient and achieves clinically acceptable stable maxillary expansion. In this article, we will discuss the role of total arch movement and MARPE in widening the scope of non-surgical orthodontic treatment, despite the inherent limitations of miniscrews' mechanical aspects. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
175. Ladder-like polysilsesquioxanes with antibacterial chains and durable siloxane networks
- Author
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Jinkee Hong, Sung Hwan Choi, Daheui Choi, Myung-Jin Lee, Sungwon Jung, Sohyeon Park, Jae-Sung Kwon, Jiwoong Heo, Woojin Choi, and Ji Yeong Kim
- Subjects
chemistry.chemical_classification ,Materials science ,General Chemical Engineering ,Quaternary ammonium cation ,02 engineering and technology ,General Chemistry ,Adhesion ,engineering.material ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Industrial and Manufacturing Engineering ,0104 chemical sciences ,chemistry.chemical_compound ,Membrane ,Chemical engineering ,chemistry ,Coating ,Siloxane ,Nano ,engineering ,Environmental Chemistry ,0210 nano-technology ,Hybrid material ,Alkyl - Abstract
Significant progress has been made in endowing biomedical materials with antibacterial properties. However, the commercialization of these systems still poses various practical challenges. In this study, we report a facile technique for the preparation of practical and efficient antibacterial coatings based on well-defined polysilsesquioxane (PSQ) structures containing quaternary ammonium cation and long alkyl chains. PSQ is a hybrid material containing organic groups within a flexible and robust siloxane network, and can be endowed with different functions according to the synthetic conditions employed in the sol-gel process. However, depending on the synthetic precursors, a non-uniform PSQ structure can be formed, which limits the functions and stability of the resulting material. Accordingly, we synthesized PSQs with homogeneously distributed quaternary ammonium cation and long alkyl chains, using optimized synthetic conditions. The PSQs were coated on devices via self-assembly, and the thickness of the coating could be controlled from the nano- to the microscale depending on the deposition time. All coated substrates exhibited more than 60% bacterial reduction rate for three types of bacteria compared to the control groups. The coating inhibited the activity of the membrane adhesins, which prevented the strong adhesion of bacteria to the surfaces. Furthermore, the coated substrates also showed an increased mechanical strength in bulk strength tests. The nanoscale coatings notably increased the hardness of the dental substrates more than twofold compared to that of the control. The easy preparation and efficacy of the PSQs highlight their applicability as antibacterial coatings in various medical devices requiring high durability.
- Published
- 2020
176. Environmental and economic loss analyses of the oil discharge from shipwreck for salvage planning
- Author
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Jung-Yeul Jung, Ki-Cheol Park, Sung-Hwan Choi, and Moonjin Lee
- Subjects
0106 biological sciences ,Pollution ,business.industry ,Oceans and Seas ,010604 marine biology & hydrobiology ,media_common.quotation_subject ,Wind ,010501 environmental sciences ,Aquatic Science ,Oceanography ,01 natural sciences ,Marine pollution ,Flood tide ,Aquaculture ,Environmental protection ,Open sea ,Oil spill ,Environmental science ,Petroleum Pollution ,Environmental Pollution ,business ,Environmental Monitoring ,0105 earth and related environmental sciences ,media_common - Abstract
In this study, we carry out environmental and economic loss analyses of the oil discharge from the shipwreck Jeh Hun. By performing 500 simulations of hypothetical oil spill cases, we obtain the minimum and worst damage cases. In the minimum damage case, there is just marine pollution without coastal pollution or aquaculture farm pollution. On the other hand, in the worst damage case, there is serious marine pollution, coastal pollution, and aquaculture pollution. The main purpose of the environmental and economic loss analyses is to support salvage planning for the shipwreck, because we have to consider the oil discharge from the shipwreck during oil removal and salvage. The results of this study show that the best salvage time is early morning in winter, when the northwest wind and maximum flood tide are dominant resulting in the spilt oil going forward into the open sea without coastal pollution and aquaculture pollution.
- Published
- 2020
177. Incorporating Aminated Nanodiamonds to Improve the Mechanical Properties of 3D-Printed Resin-Based Biomedical Appliances
- Author
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Sung Hwan Choi, Ji-Young Seo, Jaehun Yu, Utkarsh Mangal, and Jae-Sung Kwon
- Subjects
Materials science ,General Chemical Engineering ,aminated nanodiamond ,02 engineering and technology ,mechanical properties ,Article ,lcsh:Chemistry ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Flexural strength ,nanocomposites ,General Materials Science ,Composite material ,Methyl methacrylate ,Nanodiamond ,Elastic modulus ,Nanocomposite ,Izod impact strength test ,030206 dentistry ,021001 nanoscience & nanotechnology ,Poly(methyl methacrylate) ,lcsh:QD1-999 ,chemistry ,visual_art ,Vickers hardness test ,visual_art.visual_art_medium ,poly (methyl methacrylate) ,0210 nano-technology ,additive manufacturing - Abstract
The creation of clinically patient-specific 3D-printed biomedical appliances that can withstand the physical stresses of the complex biological environment is an important objective. To that end, this study aimed to evaluate the efficacy of aminated nanodiamonds (A-NDs) as nanofillers in biological-grade acrylate-based 3D-printed materials. Solution-based mixing was used to incorporate 0.1 wt% purified nanodiamond (NDs) and A-NDs into UV-polymerized poly(methyl methacrylate) (PMMA). The ND and A-ND nanocomposites showed significantly lower water contact angles (p <, 0.001) and solubilities (p <, 0.05) compared to those of the control. Both nanocomposites showed markedly improved mechanical properties, with the A-ND-containing nanocomposite showing a statistically significant increase in the flexural strength (p <, 0.001), elastic modulus (p <, 0.01), and impact strength (p <, 0.001) compared to the control and ND-containing groups. The Vickers hardness and wear-resistance values of the A-ND-incorporated material were significantly higher (p <, 0.001) than those of the control and were comparable to the values observed for the ND-containing group. In addition, trueness analysis was used to verify that 3D-printed orthodontic brackets prepared with the A-ND- and ND-nanocomposites exhibited no significant differences in accuracy. Hence, we conclude that the successful incorporation of 0.1 wt% A-ND in UV-polymerized PMMA resin significantly improves the mechanical properties of the resin for the additive manufacturing of precisive 3D-printed biomedical appliances.
- Published
- 2020
178. Comprehensive orthodontic treatment of a young girl with an odontogenic keratocyst and impacted teeth in the mandible
- Author
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Hyoung Seon Baik, Won-Kyeong Baik, and Sung Hwan Choi
- Subjects
050402 sociology ,Mandibular symphysis ,media_common.quotation_subject ,medicine.medical_treatment ,Marsupialization ,Case Report ,Orthodontics ,Orthodontic traction ,03 medical and health sciences ,0302 clinical medicine ,stomatognathic system ,0504 sociology ,medicine ,Premolar ,Cyst ,Girl ,Keratocyst ,media_common ,Impacted teeth ,Impaction ,business.industry ,05 social sciences ,030206 dentistry ,medicine.disease ,Odontogenic keratocyst ,Odontogenic ,stomatognathic diseases ,medicine.anatomical_structure ,medicine.symptom ,business - Abstract
Odontogenic keratocysts (OKCs) are one of the most aggressive cysts in the oral and maxillofacial area because of their high recurrence rate and infiltrative behavior. In growing patients with OKCs, a radical treatment approach might cause numerous complications, including the disturbance of jaw growth and loss of the involved tooth. This case report describes successful comprehensive orthodontic treatment combined with marsupialization of the cyst in a young girl who exhibited an OKC with impacted teeth. The 10-year-old girl presented with an OKC extending from the mandibular symphysis through the left mandibular body, with ectopic impaction of the mandibular left canine and first premolar, as well as congenitally missing bilateral mandibular second premolars. Interestingly, spontaneous improvement of the positions of the ectopic impacted teeth, along with a reduction in the size of the cyst, occurred during marsupialization. The sequential use of removable and fixed appliances enabled orthodontic traction of the impacted teeth. The treatment outcome was stable at 2.5 years after the end of the treatment. We speculate that comprehensive orthodontic treatment combined with marsupialization can be an effective treatment strategy for patients with OKCs, especially when they are encountered in young, growing patients with impacted teeth.
- Published
- 2020
179. Changes in position of the hyoid bone and volume of the pharyngeal airway after mandibular setback: three-dimensional analysis
- Author
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Jin Hoo Park, Hee-Sung Kim, Sung Hwan Choi, Young-Soo Jung, and Hwi-Dong Jung
- Subjects
Three dimensional analysis ,Cephalometry ,medicine.medical_treatment ,Orthognathic surgery ,Mandible ,03 medical and health sciences ,0302 clinical medicine ,stomatognathic system ,Tongue ,medicine ,Humans ,Reduction (orthopedic surgery) ,Orthodontics ,Soft palate ,business.industry ,Hyoid bone ,Hyoid Bone ,030206 dentistry ,Position (obstetrics) ,medicine.anatomical_structure ,Malocclusion, Angle Class III ,Otorhinolaryngology ,030220 oncology & carcinogenesis ,Prognathism ,Pharynx ,Surgery ,sense organs ,Oral Surgery ,business ,Airway - Abstract
Important aspects of orthognathic surgery are the effects of skeletal movement and changes in the position of the hyoid bone, tongue, soft palate, and dimensions of the pharyngeal airway. Our aims were to evaluate the 3-dimensional changes in the pharyngeal airway and in the position of the hyoid bone after mandibular setback in 30 patients who were diagnosed with mandibular prognathism and were treated by intraoral vertical ramus osteotomy (IVRO). Three-dimensional cone-beam computed tomographic (CT) images were obtained preoperatively, one month postoperatively, and one year postoperatively. The total pharyngeal volume decreased between the preoperative state and one month and one year afterwards. The hyoid bone had moved 2.0 mm posteriorly and 3.15 mm superiorly by one month postoperatively. The position of the hyoid bone was affected by changes in posterior and superior movement of the B point at one month (r = 0.44, p = 0.015 and R = 0.63, p = 0.000, respectively) and also by superior movement of the B point at one year (r = 0.57, p = −0.001). There was an advantageous relation between posterior positional changes in the B point (mandibular setback), and volumetric changes in the hypopharyngeal and total pharyngeal airway, so maxillofacial surgeons should consider the reduction in airway when planning excessive mandibular setback.
- Published
- 2018
180. Evaluation of characteristics of the craniofacial complex and dental maturity in girls with central precocious puberty
- Author
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Hee Kyung Lee, Chung Ju Hwang, Kyung Mi Jang, Dong Fan, Min Seon Kim, and Sung Hwan Choi
- Subjects
Cephalometry ,Central precocious puberty ,Puberty, Precocious ,Orthodontics ,Mandible ,Facial Bones ,03 medical and health sciences ,0302 clinical medicine ,stomatognathic system ,Radiography, Panoramic ,Medicine ,Humans ,Gonial angle ,030212 general & internal medicine ,Craniofacial ,Child ,Lower anterior ,business.industry ,Mandibular teeth ,Skull ,Bone age ,030206 dentistry ,Original Articles ,body regions ,stomatognathic diseases ,Case-Control Studies ,Female ,Mandibular plane angle ,business ,Dental maturity ,Tooth - Abstract
Objectives: To identify unique characteristics of the craniofacial complex and dental maturity in girls with central precocious puberty (CPP). Materials and Methods: This study included 34 Korean girls with idiopathic CPP (mean age, 8.6 ± .5 years) and 28 normal healthy girls of the same chronological age. An initial evaluation of the growth pattern of the craniofacial complex and dental maturity was conducted by analyzing lateral cephalometric and panoramic radiographs. Results: The mandibular ramus height (44.4 ± 4.1 mm) and total mandibular length (10.8 ± 4.3 mm) (P = .004 and .021, respectively) were greater and the lower anterior facial height was lesser (63.2 ± 2.4 mm) (P = .040) in the CPP group than in the reference group. In addition, the gonial angle (12.9 ± 6.1°; P = .045) and the mandibular plane angle (34.9 ± 4.8°; P = .012) were smaller in girls with CPP than in normal healthy girls. All the mandibular teeth were more mature in girls with CPP (P < .001). A strong positive correlation was observed between the mandibular tooth formation stages and the presence of CPP in girls (r = .756 to .957; P < .001). Conclusions: CPP had an effect on the anteroposterior growth of the mandible in the craniofacial complex and the rotation of the mandibular plane angle. Early maturation of the mandibular teeth was observed in girls with CPP.
- Published
- 2018
181. Debonding force and shear bond strength of an array of CAD/CAM-based customized orthodontic brackets, placed by indirect bonding- An In Vitro study
- Author
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Chung Ju Hwang, Jung Yul Cha, Kwang Mahn Kim, Sung Hwan Choi, Ha Na Sha, and Hyung Seog Yu
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Dental Stress Analysis ,Materials science ,Orthodontic Brackets ,lcsh:Medicine ,Dental bonding ,03 medical and health sciences ,0302 clinical medicine ,Group (periodic table) ,Materials Testing ,Premolar ,medicine ,Shear strength ,Humans ,Bicuspid ,030212 general & internal medicine ,lcsh:Science ,Orthodontics ,Universal testing machine ,Multidisciplinary ,Bond strength ,Bracket ,lcsh:R ,Dental Bonding ,030206 dentistry ,Resin Cements ,medicine.anatomical_structure ,Microscopy, Electron, Scanning ,Computer-Aided Design ,lcsh:Q ,Adhesive ,Shear Strength - Abstract
Based on three-dimensional scanning and computer-aided design and computer-aided manufacturing (CAD/CAM) techniques, customized bracket systems are increasingly used. However, data remain limited regarding customized bracket design, characteristics, and stability. This study was undertaken to evaluate the design, bond strength, and residual adhesives of four different CAD/CAM customized brackets that were attached to human tooth specimens by indirect bonding. Thirty extracted human upper premolars were divided into five groups: Group 1, preadjusted self-ligating labial metal bracket; Group 2, lingual self-ligating metal injection molding customized bracket; Group 3, gold-casted lingual customized bracket; Group 4, labial self-ligating milled customized bracket; Group 5, labial customized resin base bracket. Except in Group 1, premolar specimens were scanned via model scanner, and the images were sent to each manufacturing company to fabricate customized brackets and transfer trays/jigs. Debonding force (DF; N) was measured by Instron universal testing machine and shear bond strength (SBS; MPa) was calculated via dividing DF by bonding area. Adhesive remnants were analyzed via stereo microscopic images. Group 2 (196.90±82.75 N) exhibited significantly higher DF than Group 1 (62.77±12.65 N); other groups exhibited similar DFs, compared with Group 1. No customized bracket groups exhibited significant differences in SBS, relative to Group 1 (6.73±1.36 MPa). However, SBS in Group 5 (11.46±7.22 MPa) was significantly higher than in Group 3 (3.58±2.14 MPa). Group 3 had significantly lower ARI scores than other groups (P
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- 2018
182. Effect of wet storage on the bioactivity of ultraviolet light- and non-thermal atmospheric pressure plasma-treated titanium and zirconia implant surfaces
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Kee Joon Lee, Hyung Seog Yu, Chung Ju Hwang, Jae-Sung Kwon, Sung Hwan Choi, Kwang Mahn Kim, Jong-Eun Kim, Jung Yul Cha, Jeong Hyun Ryu, and Eun Ha Choi
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Materials science ,Plasma Gases ,Surface Properties ,Ultraviolet Rays ,viruses ,chemistry.chemical_element ,Bioengineering ,Atmospheric-pressure plasma ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Cell Line ,Biomaterials ,Mice ,Implants, Experimental ,Materials Testing ,Ultraviolet light ,Animals ,Cubic zirconia ,Irradiation ,Titanium ,Aqueous solution ,fungi ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Atmospheric Pressure ,chemistry ,Mechanics of Materials ,Implant ,Zirconium ,0210 nano-technology ,Protein adsorption ,Nuclear chemistry - Abstract
The aim of this study was to evaluate whether combining two treatments to avoid biological aging of the surface of titanium and zirconia implants; i.e., storage in an aqueous solution after ultraviolet light (UV) or non-thermal atmospheric pressure plasma (NTP) treatment, yielded surface bioactivity comparable to that following post-15-min UV or NTP treatment storage under air or immediately after UV or NTP treatment. Grade IV titanium discs modified by large grit sand-blasting and acid-etching (SLA) and smooth zirconia discs were irradiated with UV or NTP and their surface properties were evaluated immediately and after storage for 8 weeks in distilled H2O (dH2O) and a sealed container under air. Approximately 15–30 nm-sized nano-protrusions were formed only on SLA surfaces in dH2O immediately after UV or NTP treatment. Immediate dH2O storage after UV or NTP treatment prevented hydrocarbon contamination and maintained elevated amounts of Ti and Zr. After 8 weeks, unlike zirconia, protein adsorption, cellular adhesion, and cytoskeletal development of MC3T3-E1 cells on SLA surfaces stored in dH2O immediately after UV treatment were further exceeding those immediately after UV or NTP treatments. UV treatment of SLA implants followed by wet storage can not only maintain but also strengthen bioactivity during shelf storage.
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- 2018
183. Model Analysis of Digital Models in Moderate to Severe Crowding: In Vivo Validation and Clinical Application
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Jae Hee Yoon, Tae Hyun Choi, Hyung Seog Yu, Sung Hwan Choi, Yoon Jeong Choi, and Jung Yul Cha
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Moderate to severe ,Dental Impression Technique ,Article Subject ,genetic structures ,lcsh:Medicine ,Mandible ,General Biochemistry, Genetics and Molecular Biology ,03 medical and health sciences ,Imaging, Three-Dimensional ,0302 clinical medicine ,Image Processing, Computer-Assisted ,Maxilla ,Humans ,Tooth crowding ,Mathematics ,Orthodontics ,Reproducibility ,Crowding in ,General Immunology and Microbiology ,Significant difference ,lcsh:R ,Reproducibility of Results ,Dental Models ,030206 dentistry ,General Medicine ,Crowding ,Models, Dental ,Calipers ,Malocclusion ,Software ,030217 neurology & neurosurgery ,Research Article - Abstract
Objective. We investigated the suitability of intraoral-scan models for measuring tooth dimensions and the amount of crowding in patients with severe tooth crowding. Materials and Methods. Fifty-eight patients who had undergone intraoral scans for diagnosis were included. Cast models were divided into two groups depending on the amount of crowding, as determined by initial caliper-based measurements (mild crowding [MC] group: 4.5 mm). Twenty maxillary models and 20 mandibular models were used in this study. For the three types of models (i.e., IS digital model, C cast model, and CS digital model), the reproducibility and the precision of linear measurements were evaluated. Results. We found that linear measurements made using digital calipers on a plaster model and on the relevant software were reproducible. There was no significant difference in most linear measurements between digital models and the C model. There were differences in the amount of crowding (p<.05), although these were not clinically significant. There was no relationship between the precision of crowding in the three types of models and the severity of crowding. Conclusions. Digital models can be used for measuring crowding in both mild and severe crowding cases. However, crowding measured by digital models tends to be lesser than that measured by cast models, and this should be considered during clinical application.
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- 2018
184. Analysis of the Morphological Characteristics of the Palatal Rugae for Three-Dimensional Superimposition of Digital Models in Korean Subjects
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Jung Yul Cha, Kee Joon Lee, Kyongmin Koh, Chung Ju Hwang, and Sung Hwan Choi
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Adult ,Male ,Palate, Hard ,Article Subject ,lcsh:Medicine ,General Biochemistry, Genetics and Molecular Biology ,03 medical and health sciences ,0302 clinical medicine ,Initial visit ,Superimposition ,Medicine ,Humans ,030216 legal & forensic medicine ,Orthodontics ,General Immunology and Microbiology ,business.industry ,Rugae ,lcsh:R ,Mouth Mucosa ,Mean age ,030206 dentistry ,General Medicine ,Models, Dental ,Palatal rugae ,Female ,business ,Research Article - Abstract
Objective. The aim of this study was to evaluate the morphological characteristics of the palatal rugae in Korean subjects to determine whether the palatal rugae can be used as an appropriate reference area for three-dimensional digital model superimpositions. Materials and Methods. In total, 343 patients (110 men, 233 women; mean age, 25.6±8.2 years) who had a digital model taken at their initial visit were included, and the numbers and types of right and left palatal rugae were investigated according to the primary, secondary, and fragmentary rugae. Finally, the differences in the positions of the third primary ruga were investigated according to the presence of additional rugae posterior to the third primary ruga. Results. The number of primary palatal rugae ranged from one to six, with 43.5% of the subjects having three primary rugae and 36.1% having four primary rugae; there were no significant differences between sexes. Except for the fragment rugae, the numbers of primary and secondary rugae were not significantly different between the left and right sides. The third primary ruga was located more significantly anteriorly when there was an additional ruga posterior to the third primary ruga (P < 0.001). Conclusions. The numbers of the palatal rugae vary greatly among individuals, and this affects the anteroposterior position of the third primary ruga. When the third primary ruga is located anteriorly, care should be taken when using it as a reference area for superimposition with a digital model before and after orthodontic treatment.
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- 2018
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185. Comparative study of hydrodynamic characteristics with respect to direction of installation of gas-liquid ejector system
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Sung Hwan Choi, Ho Seong Ji, and Kyung Chun Kim
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Flow visualization ,Engineering ,Engineering drawing ,business.industry ,Water flow ,Mechanical Engineering ,Airflow ,Injector ,Mechanics ,Local Void ,law.invention ,Physics::Fluid Dynamics ,Mechanics of Materials ,law ,Homogeneity (physics) ,Air entrainment ,business ,Porosity ,Physics::Atmospheric and Oceanic Physics - Abstract
The gas-liquid two-phase ejector is a device without moving parts, in which a liquid is used to drive a gas of a low-pressure source. In this study, the effect of the direction of installation on hydrodynamic characteristics was examined using the same air/water ejector loop. The entrained air flow rates and local void fraction profiles were also measured at various water flow rates for three types of installation: horizontal, vertical-upward, and vertical-downward, and were compared. From the study, the vertical-downward installation was found to be the best in terms of air entrainment ratio and homogeneity of bubbles.
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- 2015
186. Tachycardia-bradycardia syndrome in a patient with atrial fibrillation: a case report
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Sung Lark Choi, Mi Ae Jeong, Sung Hwan Choi, and Bong Yeong Lee
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medicine.medical_specialty ,Lidocaine ,Case Report ,Sick sinus syndrome ,lcsh:RD78.3-87.3 ,sick sinus syndrome ,Internal medicine ,medicine ,artificial cardaic pacing ,Sinus rhythm ,atrial fibrillation ,cardiovascular diseases ,Sinus (anatomy) ,business.industry ,Atrial fibrillation ,medicine.disease ,Tachycardia-bradycardia syndrome ,Anesthesiology and Pain Medicine ,Blood pressure ,medicine.anatomical_structure ,lcsh:Anesthesiology ,Cardiology ,cardiovascular system ,Propofol ,business ,medicine.drug - Abstract
An 83-year-old woman was scheduled for a second transurethral resection of a bladder tumor. The preoperative electrocardiogram evaluation revealed atrial fibrillation with a slow ventricular response (ventricular rate: 59 /min). After intravenous injection of 1% lidocaine 40 mg and propofol 60 mg, the ventricular rate increased to 113 beats/min and then fell rapidly to 27 beats/min. Blood pressure was 70/40 mmHg. Later an atrial fibrillation rhythm, with a ventricular rate of 100-130 beats/min, was observed together with a sinus pause and sinus rhythm with a ventricular rate of 40-50 beats/min. An external pacemaker was applied and set at 60 mA, 40 counts. After the patient regained consciousness, she presented an alert mental state and had no chest symptoms. She was discharged 2 weeks later without complications after insertion of a permanent pacemaker.
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- 2015
187. Impact of malocclusion and common oral diseases on oral health–related quality of life in young adults
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Baek Il Kim, Sung Hwan Choi, Jung Yul Cha, and Chung Ju Hwang
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Adult ,Male ,Index of Orthodontic Treatment Need ,Activities of daily living ,Adolescent ,Cross-sectional study ,Pain ,Dentistry ,Oral Health ,Orthodontics ,Physical examination ,Social Skills ,Young Adult ,Quality of life ,Activities of Daily Living ,Humans ,Medicine ,Young adult ,medicine.diagnostic_test ,DMF Index ,business.industry ,Odds ratio ,Temporomandibular Joint Disorders ,medicine.disease ,Confidence interval ,stomatognathic diseases ,Cross-Sectional Studies ,Quality of Life ,Educational Status ,Female ,Periodontal Index ,Malocclusion ,Mouth Diseases ,business ,Stress, Psychological - Abstract
The aim of this study was to assess the association between malocclusion and oral health-related quality of life in young adults without orthodontic treatment, controlling for sociodemographic factors and common oral diseases.The sample consisted of 429 Korean patients (328 men, 101 women) 18 to 32 years of age. They completed the Korean version of the oral health impact profile-14 questionnaire and had a clinical examination, including an assessment with the index of orthodontic treatment need-dental health component. We collected sociodemographic information (age, sex, and education level) and evaluated other common oral diseases (decayed, missing, and filled teeth; periodontal health status; temporomandibular disorder; and oral soft tissue diseases).Multiple logistic regression analysis showed that patients requiring extensive orthodontic treatment were more than 2.7 times as likely to have poor oral health-related quality of life as the corresponding "no treatment needed" reference group (odds ratio, 2.74; 95% confidence interval, 1.60-4.59; P0.001). Severe malocclusion is significantly associated with functional limitations, physical pain, and social disability in young adults.Malocclusion is a key factor associated with poor quality of life caused by limited oral function, pain, and social disability in young adults.
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- 2015
188. Fibrillation Number Based on Wavelength and Critical Mass in Patients Who Underwent Radiofrequency Catheter Ablation for Atrial Fibrillation
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Sung Hwan Choi, Junbeum Park, Jae Hyung Park, Minki Hwang, Young-Seon Lee, Hui Nam Pak, and Eun Bo Shim
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Male ,medicine.medical_specialty ,Refractory period ,Neural Conduction ,Biomedical Engineering ,Action Potentials ,Nerve conduction velocity ,Pulmonary vein ,Refractory ,Heart Conduction System ,Internal medicine ,Atrial Fibrillation ,medicine ,Humans ,Computer Simulation ,In patient ,Coronary sinus ,Fibrillation ,business.industry ,Models, Cardiovascular ,Atrial fibrillation ,Organ Size ,Middle Aged ,medicine.disease ,Treatment Outcome ,Pulmonary Veins ,Anesthesia ,Catheter Ablation ,Cardiology ,Female ,medicine.symptom ,business - Abstract
The heart characteristic length, the inverse of conduction velocity (CV), and the inverse of the refractory period are known to determine vulnerability to cardiac fibrillation (fibrillation number, FibN) in in silico or ex vivo models. The purpose of this study was to validate the accuracy of FibN through in silico atrial modeling and to evaluate its clinical application in patients with atrial fibrillation (AF) who had undergone radiofrequency catheter ablation. We compared the maintenance duration of AF at various FibNAF values using in silico bidomain atrial modeling. Among 60 patients (72% male, $54\pm 13$ years old, 82% with paroxysmal AF) who underwent circumferential pulmonary vein isolation (CPVI) for AF rhythm control, we examined the relationship between FibN AF and postprocedural AF inducibility or induction pacing cycle length (iPCL). Clinical FibNAF was calculated using left atrium (LA) dimension (echocardiogram), the inverse of CV, and the inverse of the atrial effective refractory periods measured at proximal and distal coronary sinus. In silico simulation found a positive correlation between AF maintenance duration and FibNAF ( $R = 0.90$ , $p ). After clinical CPVI, FibNAF ( $0.296\pm 0.038$ versus $0.192\pm 0.028$ , $p ) was significantly higher in patients with postprocedural AF inducibility ( $n = 41$ ) than in those without ( $n = 19$ ). Among 41 patients with postprocedural AF inducibility, FibNAF ( $P = 0.935$ , $p ) had excellent correlations with induction pacing cycle length. FibNAF, based on LA mass and wavelength, correlates well with AF maintenance in computational modeling and clinical AF inducibility after CPVI.
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- 2015
189. Comparison of emergence times with different fresh gas flow rates following desflurane anaesthesia
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Sung Lark Choi, Bong Yeong Lee, Sung Wook Yoon, Sung Hwan Choi, Ji Seon Jeong, and Mi Ae Jeong
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Adult ,Male ,medicine.medical_specialty ,Eye opening ,Adolescent ,Consciousness ,Time based ,Biochemistry ,Time ,Remifentanil ,Young Adult ,Desflurane ,Piperidines ,Low flow anaesthesia ,Humans ,Medicine ,Fresh gas flow rate ,Isoflurane ,business.industry ,Biochemistry (medical) ,Cell Biology ,General Medicine ,Middle Aged ,Surgery ,Discontinuation ,Fresh gas flow ,Anesthesia ,Bispectral index ,Anesthesia Recovery Period ,Anesthetics, Inhalation ,Airway Extubation ,Female ,business ,Anesthetics, Intravenous ,medicine.drug - Abstract
ObjectiveTo investigate emergence times with different fresh gas flow rates, following desflurane anaesthesia.MethodsPatients undergoing surgery with desflurane anaesthesia were randomly assigned to receive fresh gas flow rates of 100% oxygen during emergence of 2 l/min (group D2), 4 l/min (group D4) or 6 l/min (group D6). Time to eye opening, spontaneous movement and extubation (emergence time) were assessed after desflurane discontinuation. The end-tidal concentration of desflurane and bispectral index were recorded at each of these timepoints.ResultsA total of 105 patients were included in the study, with 35 in each of the three groups. Mean times to extubation were 17.6 min, 9.9 min and 9.1 min in groups D2, D4 and D6, respectively. Times to eye opening, spontaneous movement and extubation in group D2 were significantly longer than in groups D4 and D6.ConclusionsThese results suggest that there is the potential to predict emergence time based on fresh gas flow rate following desflurane anaesthesia. It should therefore be possible to use a low-flow technique during the emergence period, in addition to the maintenance period, without delaying recovery if the inhaled anaesthetic is stopped at the predicted time before the end of surgery.
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- 2014
190. Antifibrotic effects of sulforaphane treatment on gingival elasticity reduces orthodontic relapse after rotational tooth movement in beagle dogs.
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Kyong-Nim Kim, Jue-Young Kim, Jung-Yul Cha, Sung-Hwan Choi, Jin Kim, Sung-Won Cho, and Chung-Ju Hwang
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OSTEOCLASTOGENESIS ,SULFORAPHANE ,CORRECTIVE orthodontics ,DOGS ,GINGIVAL fluid - Published
- 2020
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191. Stability of bimaxillary surgery involving intraoral vertical ramus osteotomy with or without presurgical miniscrew-assisted rapid palatal expansion in adult patients with skeletal Class III malocclusion.
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Yoon-Soo Ahn, Sung-Hwan Choi, Kee-Joon Lee, Young-Soo Jung, Hyoung-Seon Baik, and Hyung-Seog Yu
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MAXILLA surgery ,OSTEOTOMY ,MALOCCLUSION ,DENTAL screws ,DENTAL occlusion - Published
- 2020
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192. P-12: 3-D TCAD Simulation for Describing Intrinsic Fluctuations in Polycrystalline Silicon Thin Film Transistors
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Gun-Shik Kim, Seunghyun Jang, Dongjo Kim, Sung-Hwan Choi, Moon-Hyun Yoo, and ByoungTaek Son
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010302 applied physics ,Materials science ,business.industry ,Transistor ,engineering.material ,01 natural sciences ,law.invention ,Condensed Matter::Materials Science ,AMOLED ,Polycrystalline silicon ,law ,Thin-film transistor ,0103 physical sciences ,engineering ,Electronic engineering ,Optoelectronics ,Grain boundary ,Crystallite ,business ,Voronoi diagram ,Diode - Abstract
In this work, we investigate the influence of grain boundaries on the performance of polycrystalline silicon thin-film transistors (poly-Si TFTs) for high resolution active-matrix organic light-emitting diode (AMOLED) displays using Voronoi diagram. The novel 2-D Voronoi polycrystalline grain structure can show a more realistic electrical parameter variability when the channel dimension is scaled down for high-resolution display. Using a proposed method, the impact of polycrystalline granular structure controlled by crystallization process is identified. Further, we predict the effect of grain boundary-induced variations under different laser annealing process, such as Excimer Laser Annealing (ELA).
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- 2016
193. Effect of the ultraviolet light treatment and storage methods on the biological activity of a titanium implant surface
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Jae Hoon Lee, Kwang Mahn Kim, Chung Ju Hwang, Eun Ha Choi, Sung Hwan Choi, Hyung Seog Yu, Kee Joon Lee, Jung Yul Cha, and Won Seok Jeong
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Materials science ,Time Factors ,Vacuum ,Surface Properties ,Ultraviolet Rays ,Analytical chemistry ,chemistry.chemical_element ,02 engineering and technology ,Dielectric barrier discharge ,Microscopy, Atomic Force ,Contact angle ,03 medical and health sciences ,Mice ,0302 clinical medicine ,Adsorption ,X-ray photoelectron spectroscopy ,X-Ray Diffraction ,Albumins ,Ultraviolet light ,Cell Adhesion ,Animals ,General Materials Science ,Irradiation ,General Dentistry ,Titanium ,Osteoblasts ,Air ,Photoelectron Spectroscopy ,technology, industry, and agriculture ,Water ,030206 dentistry ,021001 nanoscience & nanotechnology ,chemistry ,Mechanics of Materials ,0210 nano-technology ,Hydrophobic and Hydrophilic Interactions ,Protein adsorption ,Nuclear chemistry - Abstract
Objective We evaluated whether the biological activity of the surface of titanium, when stored in an aqueous solution, in low vacuum, and under ambient conditions after ultraviolet light (UV) treatment is comparable to that of the surface immediately after UV treatment for 15 min and that after dielectric barrier discharge (DBD) plasma treatment for 15 min. Methods Grade IV titanium discs with machined surfaces were irradiated with UV and their surface properties were evaluated immediately and after storage for 28 days in distilled H 2 O (dH 2 O), a vacuum desiccator (31.325 kPa), and a sealed container under air. Their surface characteristics were evaluated by atomic force microscopy, X-ray diffraction, contact angle analysis, and X-ray photoelectron spectroscopy. Biological activities were determined by analyzing the albumin adsorption, MC3T3-E1 cell adhesion, and cytoskeleton development. Results Hydrophilicity of titanium surfaces stored in dH 2 O was comparable to that immediately after UV treatment and higher than that immediately after DBD plasma treatment ( P 0.001). Storage in dH 2 O and in low vacuum immediately after UV treatment prevented hydrocarbon contamination and maintained elevated amounts of titanium and oxygen. After 28 days, protein adsorption, cellular adhesion, and cytoskeletal development of MC3T3-E1 cells on the titanium surfaces stored in dH 2 O were significantly enhanced compared to those stored in low vacuum and under ambient conditions while being comparable to those immediately after UV and DBD plasma treatments. Significance UV treatment of the titanium implants followed by wet storage is useful for maintaining enhanced biological activity and overcoming biological aging during shelf storage.
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- 2017
194. Overcoming the biological aging of titanium using a wet storage method after ultraviolet treatment
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Jae Hoon Lee, Kwang Mahn Kim, Chung Ju Hwang, Sung Hwan Choi, Kee Joon Lee, Eun Ha Choi, Jung Yul Cha, Won Seok Jeong, and Hyung Seog Yu
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Surface Properties ,Ultraviolet Rays ,Science ,Cell Culture Techniques ,chemistry.chemical_element ,02 engineering and technology ,medicine.disease_cause ,Article ,Cell Line ,Contact angle ,03 medical and health sciences ,Mice ,0302 clinical medicine ,Adsorption ,X-ray photoelectron spectroscopy ,Albumins ,medicine ,Cell Adhesion ,Animals ,Humans ,Irradiation ,Titanium ,Multidisciplinary ,Aqueous solution ,030206 dentistry ,021001 nanoscience & nanotechnology ,chemistry ,Medicine ,0210 nano-technology ,Reactive Oxygen Species ,Ultraviolet ,Nuclear chemistry ,Protein adsorption - Abstract
We evaluated whether the biological activity of the surface of titanium, when stored in an aqueous solution after ultraviolet (UV) treatment, is comparable to that of the surface immediately after UV treatment. We subjected Grade IV titanium discs with machined surfaces to UV radiation for 15 min and then tested them immediately and after storage for 28 days, with and without distilled H2O (dH2O). We evaluated the surface characteristics using surface profiling, contact angle analysis, X-ray photoelectron spectroscopy, and in terms of the surface zeta-potential. We determined the level of biological activity by analysing albumin adsorption, MC3T3-E1 and human mesenchymal cell adhesion and cytoskeleton development, as well as the production of intracellular reactive oxygen species between groups. The surface characteristics produced by the UV irradiation were maintained in dH2O for 28 days. We found that titanium stored in dH2O for 28 days after UV treatment exhibited enhanced protein adsorption, cell attachment, and cytoskeleton development. Titanium stored in dH2O for 28 days after UV irradiation exhibited a lower level of oxidative stress, comparable to that of the titanium immediately after UV treatment. UV treatment combined with wet storage can be used as a means of overcoming the biological aging of titanium.
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- 2017
195. Rock preference of planulae of jellyfish Aurelia aurita (Linnaeus 1758) for settlement in the laboratory
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Changhoon Han, Won-Gyu Park, Sung-Hwan Choi, and Won Duk Yoon
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Basalt ,Gabbro ,biology ,Schist ,Geochemistry ,Mineralogy ,Oceanography ,biology.organism_classification ,Conglomerate ,Rhyolite ,Substrate (aquarium) ,Aurelia aurita ,Geology ,Gneiss - Abstract
Planulae of Aurelia aurita were exposed to 11 types of rocks (basalt, gabbro, granite, rhyolite, sandstone, limestone, conglomerate, gneiss, quartzite, marble and schist) to examine their attachment preference among rock material and position. Numbers of attached polyps was the highest on marble and the least on limestone. Their preference with regard to settling position was the same among the rocks, showing the highest density of polyps on the underside (88.5%) compared to upper (23.6%) and perpendicular sides (10.3%) of rock. The results showed that while position preference is more important than rock property, higher numbers of polyps were observed in rocks with a medium surface hardness.
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- 2014
196. Unpredictability of soft tissue changes after camouflage treatment of Class II division 1 malocclusion with maximum anterior retraction using miniscrews
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Yoon Jeong Choi, Sung Hwan Choi, Kayoung Kim, Jung Yul Cha, Chung Ju Hwang, and Eunhee Choi
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Male ,Cephalometry ,Bone Screws ,Dentistry ,Orthodontics ,Mandibular incisor ,Malocclusion, Angle Class II ,Orthodontics, Corrective ,03 medical and health sciences ,Young Adult ,0302 clinical medicine ,Incisor ,stomatognathic system ,Maxilla ,Orthodontic Anchorage Procedures ,Medicine ,Class II division 1 malocclusion ,Humans ,In patient ,030212 general & internal medicine ,Retrospective Studies ,business.industry ,Lateral cephalograms ,Soft tissue ,030206 dentistry ,Original Articles ,Craniometry ,Lip ,stomatognathic diseases ,medicine.anatomical_structure ,Treatment Outcome ,Female ,business - Abstract
Objective: To compare soft and hard tissue responses based on the degree of maxillary incisor retraction using maximum anchorage in patients with Class II division 1 malocclusion. Materials and Methods: This retrospective study sample was divided into moderate retraction ( Results: There were 2.3 mm and 3.0 mm of upper and lower lip retraction, respectively, in the moderate group; and 4.0 mm and 5.3 mm, respectively, in the maximum group. In the moderate group, the upper lip was most influenced by posterior movement of the cervical point of the maxillary incisor (β = 0.94). The lower lip was most influenced by posterior movement of B-point (β = 0.84) and the cervical point of the mandibular incisor (β = 0.83). Prediction was difficult in the maximum group; no variable showed a significant influence on upper lip changes. The lower lip was highly influenced by posterior movement of the cervical point of the maxillary incisor (β = 0.50), but this correlation was weak in the maximum group. Conclusions: Posterior movement of the cervical point of the anterior teeth is necessary for increased lip retraction. However, periodic evaluation of the lip profile is needed during maximum retraction of the anterior teeth because of limitations in predicting soft tissue responses.
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- 2016
197. Novel anti-biofouling bioactive calcium silicate-based cement containing 2-methacryloyloxyethyl phosphorylcholine
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Ji-Young Kim, Jae-Sung Kwon, Myung-Jin Lee, Sungil Jang, Dohyun Kim, Chung Ju Hwang, Kwang Mahn Kim, Sung Hwan Choi, and Jeong Hyun Ryu
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Glycerol ,Dental Cements ,02 engineering and technology ,Pathology and Laboratory Medicine ,Physical Chemistry ,Mineralization (biology) ,chemistry.chemical_compound ,0302 clinical medicine ,Coated Materials, Biocompatible ,Medicine and Health Sciences ,Materials ,Multidisciplinary ,Antimicrobials ,Monomers ,Drugs ,Adhesion ,021001 nanoscience & nanotechnology ,Bacterial Pathogens ,Chemistry ,Compressive strength ,Medical Microbiology ,Physical Sciences ,Cements ,Calcium silicate ,Medicine ,Methacrylates ,Sorption ,Pathogens ,0210 nano-technology ,Research Article ,Science ,Phosphorylcholine ,Bacterial Disk Diffusion ,Materials Science ,chemistry.chemical_element ,Balanced salt solution ,Enterococcus Faecalis ,Calcium ,Microbiology ,Antibiotic Susceptibility Testing ,03 medical and health sciences ,Microbial Control ,Binders ,Microbial Pathogens ,Pharmacology ,Bacteria ,Silicates ,Organisms ,Biology and Life Sciences ,030206 dentistry ,Calcium Compounds ,Polymer Chemistry ,Pharmacologic Analysis ,chemistry ,Antibacterials ,Adsorption ,Enterococcus ,Nuclear chemistry - Abstract
Calcium silicate-based cements (CSCs) are commonly used for endodontic procedures; however, their antibacterial effects are limited. The objective of this study was to develop a 2-methacryloyloxyethyl phosphorylcholine (MPC)-incorporated CSC with improved antibacterial properties, while maintaining the original advantageous features of CSC. MPC was incorporated into a commercial CSC (Endocem MTA) at 0 wt% (control), 1.5%, 3.0 wt%, 5.0 wt%, 7.5 wt%, and 10 wt%. The setting time, compressive strength, water sorption, and glycerol contact angle were measured. Protein absorption was measured and bacterial adhesion on the surface was evaluated using Enterococcus faecalis. The bactericidal effect was examined by the disc diffusion test. Mineralization ability was assessed based on calcium ion deposition, as assessed by alizarin red staining, after immersion into Hank's balanced salt solution for 7 days. High concentrations of MPC in CSC (7.5 wt% and 10 wt%) increased the setting time, reduced compressive strength, and reduced wettability. MPC (3 wt%) had greater protein repellent and anti-biofouling effects than those of control and test materials (P < 0.001). However, no bactericidal effect was observed for any control or test materials. There was greater calcium ion deposition on the surface of MPC-supplemented CSC than on the control (P < 0.001). The addition of 3 wt% MPC polymer to CSC confers protein-repellent properties and reduced bacterial attachment, with the potential for improved mineralization.
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- 2019
198. Evaluation of skeletal maturity in the cervical vertebrae and hand-wrist in relation to vertical facial types
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Ye Seul Lee, Kyung Ho Kim, Sung Hwan Choi, and Chung Ju Hwang
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050402 sociology ,Radiography ,Orthodontics ,Mandibular angle ,03 medical and health sciences ,0302 clinical medicine ,0504 sociology ,Vertical facial type ,medicine ,Skeletal maturity ,Hand wrist ,business.industry ,05 social sciences ,Bone age ,030206 dentistry ,medicine.disease ,medicine.anatomical_structure ,Original Article ,Skeletal maturity indicators ,Mandibular plane angle ,Malocclusion ,business ,Cervical vertebrae - Abstract
Objective To evaluate differences in skeletal maturity in relation to vertical facial types and to compare differences in the skeletal maturity of the cervical vertebrae and hand-wrist in females. Methods This study included 59 females aged 7 to 9 years with skeletal Class I malocclusion. The participants were categorized into three groups (low, normal, and high) according to the mandibular plane angle. Skeletal maturity was measured using skeletal maturity indicators (SMIs) and the Tanner-Whitehouse III (TW3) method on hand-wrist radiographs and by using cervical vertebrae maturation indicators (CVMIs) on lateral cephalometric radiographs. Results The SMI was higher in the high-angle group than in the low-angle group (p = 0.014). The median TW3 bone age was 11.4 months higher in the high-angle group than in the low-angle group (p = 0.032). There was no significant difference in CVMI among the three groups. Skeletal maturity showed a weakly positive correlation with the mandibular plane angle (SMI, r = 0.391; TW3, r = 0.333; CVMI, r = 0.259). Conclusions The skeletal maturity of the hand-wrist in females with a high mandibular plane angle was higher than that in females with a low mandibular plane angle. Obtaining additional hand-wrist radiographs may facilitate evaluation of skeletal maturity of females. In females with a high mandibular angle, the time to commence orthodontic treatment may be earlier than that in females with a low mandibular angle.
- Published
- 2019
199. Respiratory Outcomes at 12 Months of Corrected Age of Preterm Infants with Severe Bronchopulmonary Dysplasia Requiring Protracted Invasive Ventilation
- Author
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Sung Hwan Choi, Seung Han Shin, Ee-Kyung Kim, and Han Suk Kim
- Subjects
Pediatrics ,medicine.medical_specialty ,business.industry ,Postmenstrual Age ,Gestational age ,Lung injury ,medicine.disease ,Bayley Scales of Infant Development ,Cerebral palsy ,Bronchopulmonary dysplasia ,Breathing ,medicine ,Pulmonary hemorrhage ,business - Abstract
Objective: The objective of this study was to describe respiratory and neurodevelopmental outcomes in infants with severe bronchopulmonary dysplasia (BPD) who needed invasive ventilation until 36 weeks’ postmenstrual age (PMA). Methods: A retrospective observational single-center study was conducted in our hospital. Eighty preterm infants born between January 2007 and December 2016 with less than 28 weeks’ gestational age and classified as having severe BPD were included in the study. Patients with invasive ventilation at 36 weeks’ PMA (invasive group) were compared with those with noninvasive ventilation (noninvasive group) in terms of perinatal characteristics and postnatal outcomes. Results: Antenatal characteristics and basic patient characteristics were comparable between the two groups. Incidence of pulmonary hemorrhage (13.6 vs. 1.7%, P=0.061) and clinical sepsis (66.7 vs. 31.0%, P=0.004) was more in the invasive group. Invasive group had longer hospital stay (133.50± 104.52 vs. 114.00±24.71 days, P=0.031), higher rates of readmission due to respiratory problems before 12 months of corrected age (57.1 vs. 32.1%, P=0.045), higher rates of having a tracheostomy (22.7 vs. 1.7%, P=0.005), and higher rates of infants with respiratory support at a corrected age of 6 months (22.7 vs. 3.5%, P=0.016). Neurodevelopmental outcomes including Bayley Scales of Infant Development-III, cerebral palsy, hearing aid, blindness, and composite outcome of them revealed no differences between the two groups. Conclusion: Invasive ventilation until postmenstrual age of 36 weeks does not predict poorer neurodevelopmental outcomes in infants with severe BPD. However, the invasive group was more prone to develop respiratory problems after discharge.
- Published
- 2019
200. Effect of wet storage on the bioactivity of ultraviolet light- and non-thermal atmospheric pressure plasma-treated titanium and zirconia implant surfaces
- Author
-
Sung Hwan Choi, Sun Mi Kwon, and Hwang Chung-Ju
- Subjects
Materials science ,chemistry ,Thermal ,Ultraviolet light ,chemistry.chemical_element ,Cubic zirconia ,Atmospheric-pressure plasma ,Implant ,Oral Surgery ,Composite material ,Titanium - Published
- 2018
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