• Journal of Dental Rehabilitation and Applied Science
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• v.36 no.4
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• pp.242-253
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• 2020

Purpose: The aim of this study was to compare the accuracy of dies fabricated using 3D printing system to conventional method and to evaluate overall volumetric changes by arranging the superimposed surfaces. Materials and Methods: A mandibular right first molar from a dental model was prepared, scanned and fabricated with composites of polyetherketoneketone (PEKK). Master dies were classified into 4 groups. For the conventional method, the impression was taken with polyvinylsiloxane and the impression was poured with Type IV dental stone. For the 3D printing, the standard die was scanned and converted into models using three different 3D printers. Each of four methods was used to make 10 specimens. Scanned files were superimposed with the standard die by using 3D surface matching software. For statistical analysis, Kruskal-Wallis test and Mann-Whitney U test were done (P < 0.05). Results: Compared to the standard model, the volumetric changes of dies fabricated by each method were significantly different except the models fabricated by conventional method and 3D printer of Stereolithography (P < 0.05). The conventional dies showed the lowest volumetric change than 3D printed dies (P < 0.05). 3D printed dies fabricated by Stereolithography showed the lowest volumetric change among the different 3D printers (P < 0.05). Conclusion: The conventional dies were more accurate than 3D printed dies, though 3D printed dies were within clinically acceptable range. Thus, 3D printed dies can be used for fabricating restorations.

• Journal of Digital Convergence
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• v.19 no.1
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• pp.475-483
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• 2021

The purpose of this study is to identify the temporal and spatial characteristics of pass accuracy by utilizing the second processing data and official records collected from the 2018 FIFA World Cup Russia video data. For a total of 128 games, the success rate of passes based on the results of the game, passing time, and passing position was two-way ANOVA with repeated measure. The results showed no difference between winning and losing groups, and no interaction effects were found for passing time and location. The difference in passing time was high in the first half, with the highest success rate in the middle of the first half (79.2%) and the middle of the second half (77.9%) in the 15~30 minutes and the 60~75 minutes. Pass success rates were in the order of defense-midfield area (83.9%), midfield-attack area (81.7%), defense area (70.6%) and attack area (61.1%). In conclusion, there was no difference in the passing success rate of the winning and losing teams depending on the characteristics of the relative competitive strength of the World Cup games, and it is believed that follow-up research is needed to analyze the game contents rather than the factors of the winning and losing in the future.

• Journal of Dental Rehabilitation and Applied Science
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• v.37 no.4
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• pp.225-231
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• 2021

There are many studies on the indications and efficacy of splint therapy commonly used in patients with temporomandibular disorders (TMD). However, there have been no studies on the splint weaning in terms of the splint use tapering period in relation to symptom improvement of TMD. This retrospective study aims to analyze a proper splint weaning method in patients with TMD based on symptom improvement. Materials and Methods: The authors examined 130 TMD patients with TMJ disorders, masticatory muscle disorders, and clenching/bruxism who had received splint therapy (occlusion stabilization splint, anterior positioning splint) of patients who visited the Department of Orofacial Pain and Oral Medicine at Yonsei University Dental Hospital from 2015 to 2020. They were evaluated according to the method to wean splints. Results: The mean splint therapy period was 29.0 months, during which patients wore splints 7 days a week for 8.4 months, 3 - 4 days a week for 9.5 months, and finally 1 - 2 days a week for 11.1 months (a total of 29.0 months, about 2.5 years). Conclusion: It seems that TMD symptoms can be alleviated and side effects such as occlusal change can be minimized if patients wear a splint 7 days a week for the first 6 months, followed by 3 - 4 days a week for the next 6 to 18 months, and finally 1 - 2 days a week after 18 months.

• Journal of Dental Rehabilitation and Applied Science
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• v.38 no.2
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• pp.71-80
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• 2022

Although low translucency 3 mol% yttria stabilized tetragonal zirconia polycrystal has excellent mechanical properties, it has limited application as a monolithic prosthesis. To improve these optical limitations, translucent zirconia has improved esthetics due to an increase in the cubic phase; however, it is accompanied by a decrease in mechanical properties simultaneously. Lithium disilicate has improved its mechanical properties through crystal size reduction and various heat treatment methods; therefore, its clinical application range is continuously increasing. Translucent zirconia shows a wide distribution of physical properties depending on the yttria content and lithium disilicate according to the size and density of crystal grains. As a result, the indications for translucent zirconia and lithium disilicate are increasing. Therefore, in this literature review, we intend to examine the rationale behind the material selection criteria in clinical situations and considerations for designing fixed dental prostheses including pontic, in particular, by summarizing recent studies.

• Journal of Korea Entertainment Industry Association
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• v.15 no.1
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• pp.171-180
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• 2021

The present study investigated the effects of dynamic tubing gait (DTG II) program on the balancing ability for the promotion of life care of patients with chronic stroke. In the study, 25 sessions of DTG II program (30 minutes per session, 5 sessions per week, for a total of 5 weeks) were applied to 10 patients with chronic stroke. To determine the effects of DTG II program for improving balance, surface electromyography(external oblique, erector spinae, iliopsoas, gluteus maximus), symmetry index test on three pelvic axes, and dynamic gait index test were performed before and after the intervention. The results showed statistically significant differences between preand post-intervention measurements of the gluteus maximus muscle at early and mid-stance phases(p<.05). The pelvic symmetry index differed significantly between pre- and post-intervention measurements of diagonal and rotational movement(p<.05). Comparison of dynamic gait index also showed statistically significant differences between pre- and post-intervention measurements(p<.05). Based on these findings, it was determined that the DTG II program was able to improve the balancing ability of patients with chronic stroke by activating their trunk muscles and improving the symmetry of diagonal pelvic movement and rotation. Therefore, DTG II program is recommended as an interventional method to improve life-care through improving the balancing ability of patients with chronic stroke.

• Journal of Korea Entertainment Industry Association
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• v.14 no.6
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• pp.269-277
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• 2020

The purpose of this study is to investigate the recovery of sensation and the restoration of upper limb function according to transcranial direct current stimulation over the primary somatosensory cortex in patients with chronic stroke with sensory deficit. 20 patients with chronic stroke divided into 10 experimental groups and 10 control groups. Patients received transcranial direct current stimulations over the primary somatosensory cortex on the side of the stroke lesion, and The control group applied sham tDCS to the same location. Intervention was conducted 5 times a week, 20 minutes per session for a total of 2 weeks. Assessment was performed using the Erasmus MC modifications to the Nottingham Sensory Assessment(EmNSA), Semmes-Weinstein monofilament examination(SWME) for somatosensory, and Fugle-Meyer Assessment(FMA), Motor Activity Log(MAL), and accelerometer for upper extremity function. Assessment was conducted before and after the intervention. As a result of the study, the experimental group showed a significant improvement in the overall tactile sense, proprioception, cortical sense, and perception sensitivity than the control group, and showed a statistically significant difference in the usage amount of the upper limb. Based on the results of this study, it is thought that the possibility of effective clinical application of transcranial direct current stimulation for recovery of somatosensory and upper extremity function is thought to be increased.

• Journal of Korea Entertainment Industry Association
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• v.14 no.8
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• pp.237-244
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• 2020

Sensory impairment is common following a stroke. Tactile afferent inputs from the plantar foot provide important information to the central nervous system to generate balance. The present study, which recruited 50 stroke patients, aims to determine the relationship between plantar tactile sensory threshold (PTST) and balance in patients with stroke. The PTST was evaluated at two sites (hallux and heel) using Semmes-Weinstein monofilaments. The balance abilities were measured by the degree of weight distribution in quiet standing (QS) and sitting-to-standing position (STS) using a MTD system and Berg balance scale (BBS). The hallux and heel sensory thresholds (ST) in the affected side were higher than the non-affected side (P < 0.05). The degree of weight distribution in the affected side was lower than the non-affected side. QS and STS showed P < 0.05, with BBS score of 36.00 ± 1.53. The hallux ST in the affected side correlated with BBS (r = -0.444, P < 0.05), QS (r = -0.332, P < 0.05), and STS (r = -0.390, P < 0.05), whereas the heel ST in the affected side correlated with BBS (r = -0.467, P < 0.05), QS (r = -0.532, P < 0.05), and STS (r = - 0.516, P < 0.05), suggesting that higher detected PTST might have an influence on the decreasing balance abilities. The study of sensory threshold in patients with stroke will help their rehabilitation and sensory evaluation.

• Therapeutic Science for Rehabilitation
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• v.11 no.4
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• pp.85-97
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• 2022

Purpose : This study aimed to investigate the effects of a digital pegboard training program with visual and auditory feedback on hand function and visual perception in stroke patients. Methods : Twenty two participants were randomly assigned to an experimental or control group. The experimental group received training using a digital pegboard training program with visual and auditory feedback (n=11), while traditional occupational therapy was administered to the control group (n=11). Hand function was assessed before and after the intervention using the Nine-Hole Peg Test and manual function test (MFT), while visual perception was assessed using the Motor-Free Visual Perception Test-3rd edition (MVPT-3). Results : Following the intervention, both the experimental and control groups showed significant improvements in performance in the Nine-Hole Peg Test and MVPT-3 (p<.05). The improvement on both tests was significantly greater in the experimental group than in the control group (p<.05). Conclusion : The results suggest that digital pegboard training with visual and auditory feedback may improve hand function and visual perception in stroke patients. Therefore, this intervention can be effective in occupational therapy to aid the recovery of stroke patients.

• Journal of Korea Entertainment Industry Association
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• v.14 no.7
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• pp.539-548
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• 2020

TTH(tension-type headache) is the most common primary headache among adults. Long-term headaches cause chronic headaches and have a better impact on daily life. The purpose of this study is to compare the contributions to TTH through AVE(audio-visual entertainment) and STM(soft tissue mobilization) suitable for management of pathogenic and psychogenic factors of TTH. The participants of this study were from 30 people who complained of intermittent or persistent headaches for more than 6 months, and 10 participants each in the AVE group, STM group, and AVE plus STM group. In the assigned group, a total of 12 sessions were performed three times a week for 4 weeks after the baseline, followed by post-test. Outcome measures measured PPTs(pressure pain thresholds), psychophysiological parameters, and EEG(electroencephalogram). The measured results were analyzed for interaction between time and group through a two way rmANOVA(repeated measurement variance analysis). As a result of the PPTs, interaction was found in the results of the right trapezius (p<.05), and the more improvement was observed in the AVE group. Therefore, through AVE based on psychological factors rather than direct access to the muscles of pathogenic factors, a positive impact on the PPTs was shown, but the average value of the psychophysiological parameters and brain waves that were not statistically significant. The amount of change was observed. Through this, it is suggested that audio-visual stimulation could be considered in the management of TTH.

• Journal of Dental Rehabilitation and Applied Science
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• v.38 no.3
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• pp.138-149
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• 2022

The clinical applicability of ceramics can be increased by analyzing the causes of fractures after fracture testing of dental ceramics. Fractography to analyze the cause of fracture of dental ceramics is being widely applied with the development of imaging technologies such as scanning electron microscopy. Setting the experimental conditions is important for accurate interpretation. The fractured specimens should be stored and cleaned to avoid contamination, and metal pretreatment is required for better observation. Depending on the type of fracture, there are dimple rupture, cleavage, and decohesive rupture mainly observed in metals, and fatigue fractures and conchoidal fractures observed in ceramics. In order to reproduce fatigue fracture in the laboratory, which is the main cause of fracture of ceramics, a dynamic loading for observing slow crack growth is essential, and the load conditions and number of loads must be appropriately set. A typical characteristic of a fracture surface of ceramic is a hackle, and the causes of fracture vary depending on the shape of hackle. Fractography is a useful method for in-depth understanding of fractures of dental ceramics, so it is necessary to follow the exact experimental procedure and interpret the results with caution.