• The Journal of the Korea Contents Association
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• v.21 no.5
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• pp.1-10
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• 2021

This study empirically confirmed 'the political bias of the YouTube recommendation algorithm' and 'the selective exposure of user' to verify the Filter Bubble phenomenon of YouTube. For the experiment, two new YouTube accounts were opened and each account was trained simultaneously in a conservative and a liberal account for a week, and the "Recommended" videos were collected from each account every two days. Subsequently, through the text mining method, the goal of the research was to investigate whether conservative videos are more recommended in a righties account or lefties videos are more recommended in a lefties account. And then, this study examined if users who consumed political news videos via YouTube showed "selective exposure" received selected information according to their political orientation through a survey. As a result of the Text Mining, conservative videos are more recommended in the righties account, and liberal videos are more recommended in the lefties account. Additionally, most of the videos recommended in the righties/lefties account dealt with politically biased topics, and the topics covered in each account showed markedly definitive differences. And about 77% of the respondents showed selective exposure.

• The Journal of Korean Academy of Prosthodontics
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• v.60 no.2
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• pp.175-186
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• 2022

A crossed occlusion resulting from the presence of posterior teeth in one arch but no opposing teeth in the opposite arch results in collapse of the vertical dimension. In this case, the patient has a class III malocclusion with crossed occlusion and anterior crossbite. In order to evaluate the proper vertical dimension, provisional denture was used to stabilize the vertical occlusal dimension for 3 months. After, provisional fixed restoration was used for the stabilizing occlusal relationship and aesthetic improvement for lip support. Definitive prosthesis in implants in the mandible and abutments in the maxillary were using Porcelain-fused-to-metal crown (PFM) crown and the maxillary unilateral edentulous area was treated with removable partial dentures. Through this, proper support of the posterior region and normal anterior occlusal relationship were formed, and the patient was able to obtain aesthetically and functionally satisfactory treatment results.

• The Journal of Advanced Prosthodontics
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• v.13 no.6
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• pp.361-372
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• 2021

PURPOSE. To improve the clinical effects of complete denture use and simplify its clinical application, a digital complete denture restoration workflow (Functional Suitable Digital Complete Denture System, FSD) was proposed and preliminary clinical evaluation was done. MATERIALS AND METHODS. Forty edentulous patients were enrolled, of which half were treated by a prosthodontic chief physician, and the others were treated by a postgraduate student. Based on the primary impression and jaw relation obtained at the first visit, diagnostic denture was designed and printed to create a definitive impression, jaw relation, and esthetic confirmation at the second visit. A redesigned complete denture was printed as a mold to fabricate final denture that was delivered at the third visit. To evaluate accuracy of impression made by diagnostic denture, the final denture was used as a tray to make impression, and 3D comparison was used to analyze their difference. To evaluate the clinical effect of FSD, visual analogue scores (VAS) were determined by both dentists and patients. RESULTS. Two visits were reduced before denture delivery. The RMS values of 3D comparison between the impression made via diagnostic dentures and the final dentures were 0.165 ± 0.033 mm in the upper jaw and 0.139 ± 0.031 mm in the lower jaw. VAS ratings were between 8.5 and 9.6 in the chief physician group, while 7.7 and 9.5 in the student group; there was no statistical difference between the two groups. CONCLUSION. FSD can simplify the complete denture restoration process and reduce the number of visits. The accuracy of impressions made by diagnostic dentures was acceptable in clinic. The VASs of both dentists and patients were satisfied.

• Journal of Periodontal and Implant Science
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• v.52 no.3
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• pp.206-219
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• 2022

Purpose: This study was performed to evaluate the influence of local application of thymoquinone (TQ) on bone healing in experimental bone defects infected with Porphyromonas gingivalis (PG). Methods: Forty-two female rats were randomly divided into 6 groups. A bone defect was created on the right tibia of all animals. The PG, PG/collagen membrane (COL) and PG/TQ/COL groups were infected with PG. In the COL and PG/COL groups, the defects were covered with a COL; in the TQ/COL and PG/TQ/COL groups, the defects were covered with a TQ-containing COL. After 28 days, all animals were sacrificed. Quantitative measurements of new bone formation and osteoblast lining, as well as semiquantitative measurements of capillary density and tissue response, were analyzed. Furthermore, the presence of bacterial infections in defect areas was evaluated. Results: The new bone formation, osteoblast number, and capillary density were significantly higher in the TQ groups than in the control groups (P<0.001, P<0.001, and P<0.01, respectively). In a comparison between the TQ/COL group, with a TQ-containing COL (TQ/COL), and the PG-infected TQ-containing COL (PG/TQ/COL) group, the newly formed bone and capillary density were higher in the TQ/COL group (P<0.01). When the control group was compared to the PG, PG/COL, and PG/TQ/COL groups in terms of tissue response, the differences were statistically significant (P<0.001, P=0.02, and P=0.041, respectively). The intensity of the inflammatory cell reaction was higher in the PG, PG/COL, and PG/TQ/COL groups (P<0.05). Conclusions: Within the limitations of this study, the local application of a TQ-containing COL positively affected bone healing even if the bone defects were infected. The results suggest that TQ increased angiogenesis and showed promise for accelerating bone defect healing. Further research is warranted to support these findings and reach more definitive conclusions.

• The Journal of Korean Academy of Prosthodontics
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• v.60 no.3
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• pp.263-275
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• 2022

The loss of posterior occlusal support leads to further complications such as collapsed occlusal plane and reduced vertical dimension, and it may cause problems such as facial appearance change, reduced chewing efficiency, and temporomandibular joint disorders. In such case, it is necessary to re-establish occlusal plane and vertical dimension properly through accurate diagnosis and predictable treatment plan. This case report presents a 71-year-old female, whose occlusal plane was collapsed and posterior restorative space was insufficient. To perform a patient-friendly full mouth rehabilitation, proper vertical dimension and occlusal plane were decided by evaluation of interocclusal space at her physiologic mandibular rest position, swallowing, pronunciation, facial appearance, and the average length of anterior teeth. And then, the fixed provisional restorations were fabricated with the new occlusal position, and evaluated for 5 months with checking adaptation of masticatory muscles and any kind of clinical symptoms occurs or not. After confirmation of functional stability and esthetic satisfaction with the newly established occlusion, final definitive restorations were fabricated and inserted in the mouth. Through the above process, the treatment result was functionally and aesthetically satisfactory.

• The Journal of Korean Academy of Prosthodontics
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• v.60 no.4
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• pp.431-441
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• 2022

The digital facebow device records the trajectory of the mandibular movement where it is then reflected on the computer-aided design software, leading to an improvement on treatment outcomes of prosthetic restorations. In this clinical case, using a digital technology, an implant placement and prosthetic restoration were done in a patient who has lost maxillary and mandibular molars. Following an intraoral scan, a surgical stent for implant surgery was fabricated based on digital diagnostic wax-up, and implants were installed. After six months of sufficient osseointegration, customized abutments and the first temporary prostheses were delivered. Then two months later, at an abutment level, an intraoral scan and digital facebow transfer device were used to mount the intraoral scan data on a virtual articulator, and record the mandibular movements. Once the second temporary prostheses were fabricated and delivered on a basis of the mandibular movement, the definitive zirconia prostheses were designed and delivered based on a stabilized occlusion that was duplicated via double scan technique.

• Journal of the Korean Orthopaedic Association
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• v.55 no.6
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• pp.534-539
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• 2020

The management of severe scoliosis remains a challenge to spine surgeons. The rapid intraoperative correction of severe scoliosis may increase the risk of perioperative complications, such as neurological compromise and implant failure. To minimize these risks, various preoperative traction methods have been employed to achieve partial correction before performing definitive corrective surgery. On the other hand, some studies have shown that one of the complications associated with halo traction could lead to cranial nerve palsy, with the sixth nerve (abducens nerve) being most commonly affected. To reduce the complications, gradual increases in the traction weight and detailed neurological examinations are needed, particularly for patients who have previously undergone brain or cervical surgery. The authors report a case of sixth cranial nerve palsy by preoperative halo-pelvic traction in patients with severe scoliosis who underwent previous decompression surgery for a Chiari I malformation with a review of the relevant literature.

• Parasites, Hosts and Diseases
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• v.60 no.4
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• pp.241-246
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• 2022

Felids are the unique definitive host of Toxoplasma gondii. The intestine of felid is the only site for initiating Toxoplasma gondii sexual reproduction. T. gondii excretes millions of infectious oocysts from the intestine, which are the primary source of infection. There are many difficulties in developing vaccines and drugs to control oocyst excretion due to the lack of an appropriate experimental model. Here, we established an in vitro feline intestinal epithelial cell (IEC) infection system and an efficient animal model of T. gondii Chinese 1 genotype, Wh6 strain (TgCtwh6). The Kunming mice brain tissues containing TgCtwh6 cysts were harvested 42-day post-infection. The bradyzoites were co-cultured with cat IECs in vitro at a ratio of 1:10. Five 3-month-old domestic cats were orally inoculated with 600 cysts each. The oocysts were detected by daily observation of cat feces by microscopy and polymerase chain reaction. We found that the parasite adhered and invaded cat IECs in vitro, transformed into tachyzoites, and then divided to form rose-like structures. These parasites eventually destroyed host cells, escaped, and finished the asexual reproduction process. Schizonts associated with sexual reproduction have not been observed during development in vitro cultured cells. However, schizonts were detected in all infected cat intestinal epithelial cells, and oocysts were presented in all cat feces. Our study provides a feasible cell model and an efficient infection system for the following studies of T. gondii sexual reproduction, and also lays a foundation to develop drugs and vaccines for blocking excretion and transmission of oocysts.

• The Journal of Korean Academy of Prosthodontics
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• v.60 no.1
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• pp.44-54
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• 2022

Without proper treatment on the multiple tooth missing area, the lack of posterior support and the supra-eruption of the teeth cause many severe complications of occlusion, vertical dimension and masticatory function. This report is a case of full-mouth rehabilitation of a patient with loss of posterior support and collapsed occlusion due to missing teeth area left untreated for a long time. The patient who is 68-year old male patient had some teeth fallen out while removing his old maxillary denture and was complaining about pain in the region of anterior teeth due to traumatic contact. The vertical dimension was corrected by 4 mm from the top cervical point of the canine through various evaluations and the edentulous area was treated with the implant fixed prostheses through computer guided implant surgery based on the diagnosis and treatment plan for definitive prostheses supported by computed tomography (CT) data analysis and CAD-CAM (Computer-aided design/computer-aided manufacturing) technique. After full mouth rehabilitation, the patient was very satisfied with remarkable improvements in mastication, function, and aesthetics.

• The Journal of Korean Academy of Prosthodontics
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• v.60 no.1
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• pp.63-70
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• 2022

Teeth wear with loss of posterior support often leads to symptoms such as irregular occlusal plane and excessive wear of anterior teeth. In such environment, establishing proper posterior support and harmonious anterior guidance and occlusal plane is recommended. In this case, the patient had excessively worn dentition with loss of posterior support, while denying surgical treatment due to her(his) history of osteoporosis, ibandronate injection, and risk of medication-related osteonecrosis of the jaw (MRONJ). To recover the vertical space needed for prosthetic restoration, full mouth rehabilitation with vertical dimension increase of remaining teeth was decided. Missing teeth in the posterior area were restored with mandibular removable partial denture. The treatment plan was determined through careful diagnosis, and every step of procedures including tooth preparation, provisional phase with the increased vertical dimension, and definitive prosthetic phase were carried out accordingly. Once the treatment was completed, the patient was satisfied functionally and esthetically. Periodic examination of oral hygiene, occlusal stability was conducted.