• Imaging Science in Dentistry
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• v.51 no.1
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• pp.27-34
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• 2021

Purpose: This study was performed to compare the ability of limited- and large-volume cone-beam computed tomography (CBCT) to display isthmuses in the apical root canals of mandibular molars. Materials and Methods: Forty human mandibular first molars with isthmuses in the apical 3 mm of mesial roots were scanned by micro-computed tomography (micro-CT), and their thickness, area, and length were recorded. The samples were examined using 2 CBCT systems, using the smallest voxels and field of view available for each device. The Mann-Whitney, Friedman, and Dunn multiple comparison tests were performed (α=0.05). Results: The 3D Accuitomo 170 and i-Cat devices detected 77.5% and 75.0% of isthmuses, respectively (P>0.05). For length measurements, there were significant differences between micro-CT and both 3D Accuitomo 170 and i-Cat(P<0.05). Conclusion: Both CBCT systems performed similarly and did not detect isthmuses in the apical third in some cases. CBCT still does not equal the performance of micro-CT in isthmus detection, but it is nonetheless a valuable tool in endodontic practice.

• Physical Therapy Korea
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• v.29 no.3
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• pp.171-179
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• 2022

Background: The application of Kinesio tape (KT) has become an alternative treatment for the reduction of edema owing to its distinct characteristics that mimic skin behavior. Although many studies have found that KT application has a positive effect on edema related to breast cancer and rehabilitation following mandibular third molar surgery, there is little evidence to support the use of KT for musculoskeletal injuries. Objects: The purpose of this study was to review the literature related to KT application for reducing edema caused by musculoskeletal disorders. Methods: A literature search (July 2022) was performed on PubMed for articles published between January 2012 and June 2022. The following keywords were used: "Kinesio taping," "Kinesio tape," "swelling," and "edema," with different combinations and derivations. Only articles available in English were included in this study. Results: Among 68 identified studies, seven met our search strategy and criteria and were included in the literature review. Five of these studies investigated musculoskeletal disorders of the knee joint; two of them reported that KT application had a positive effect on edema measured using perimetry following total knee replacement and anterior cruciate ligament reconstruction. However, the KT application did not improve swelling in patients with acute lateral ankle sprains. Pediatric patients with acute proximal phalangeal joint sprain experienced a more significant improvement in the reduction of swelling than the group using a splint. Conclusion: This literature review found discrepant evidence to support using KT for edema control in musculoskeletal disorders. Further research is needed to determine the effectiveness of KT for controlling edema following musculoskeletal injuries.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.32 no.3
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• pp.199-206
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• 2010

This study investigated the effects of strontium on osteoblastic phenotypes of cultured human periostealderived cells. Periosteal tissues were harvested from mandible during surgical extraction of lower impacted third molar. Periosteal-derived cells were introduced into cell culture. After passage 3, the periostealderived cells were further cultured for 28 days in an osteogenic induction DMEM medium supplemented with fetal bovine serum, ascorbic acid 2-phosphate, dexamethasone and at a density of $3{\times}10^4$ cells/well in a 6-well plate. In this culture medium, strontium at different concentrations (1, 5, 10, and 100 ${\mu}g$/mL) was added. The medium was changed every 3 days during the incubation period. We examined the cellular proliferation, histochemical detection and biochemical measurements of alkaline phosphatase (ALP), the RT-PCR analysis for ALP and osteocalcin, and von Kossa staining and calcium contents in the periostealderived cells. Cell proliferation was not associated with the addition of strontium in periosteal-derived cells. The ALP activity in the periosteal-derived cells was higher in 5, 10, and 100 ${\mu}g$/ml strontium-treated cells than in untreated cells at day 14 of culture. Among the strontium-treated cells, the ALP activity was appreciably higher in 100 ${\mu}g$/ml strontium-treated cells than in 5 and 10 ${\mu}g$/ml strontium-treated cells. The levels of ALP and osteocalcin mRNA in the periosteal-derived cells was also higher in strontium-treated cells than in untreated cells at day 14 of culture. Their levels were increased in a dose-dependent manner. Von Kossa-positive mineralization nodules were strongly observed in the 1 ${\mu}g$/ml strontium-treated cells at day 21 and 28 of culture. The calcium content in the periosteal-derived cells was also higher in 1 ${\mu}g$/ml strontium-treated cells at day 28 of culture. These results suggest that low concentration of strontium stimulates the osteoblastic phenotypes of more differentiated periosteal-derived cells, whereas high concentration of strontium stimulates the osteoblastic phenotypes of less differentiated periosteal-derived cells. The effects of strontium on osteoblastic phenotypes of periosteal-derived cells appear to be associated with differentiation-extent.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.29 no.3
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• pp.197-205
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• 2007

Angiogenesis is a essential part for bone formation and bone fracture healing. Vascular endothelial growth factor (VEGF), one of the most important molecules among many angiogenic factors, is a specific mitogen for vascular endothelial cells. VEGF-mediated angiogenesis is required for bone formation and repair. However, the effect of VEGF on osteoblastic cells during osteogenesis is still controversial. In recent days, substantial progress have been made toward developing tissue-engineered alternatives to autologous bone grafting for maxillofacial bony defects. Periosteum has received considerable interest as a better source of adult stem cells. Periosteum has the advantage of easy harvest and contains various cell types and progenitor cells that are able to differentiate into a several mesenchymal lineages, including bone. Several studies have reported the bone formation potential of periosteal cells, however, the correlation between VEGF signaling and cultured human periosteal cell-derived osteogenesis has not been fully investigated yet. The purpose of this study was to examine the correlation between VEGF signaling and cultured human periosteal-derived cells osteogenesis. Periosteal tissues of $5\;{\times}\;20\;mm$ were obtained from mandible during surgical extraction of lower impacted third molar from 3 patients. Periosteal-derived cells were introduced into the cell culture and were subcultured once they reached confluence. After passage 3, the periosteal-derived cells were further cultured for 42 days in an osteogenic inductive culture medium containing dexamethasone, ascorbic acid, and ${\beta}-glycerophosphate$. We evaluated the alkaline phosphatase (ALP) activity, the expression of Runx2 and VEGF, alizarin red S staining, and the quantification of osteocalcin and VEGF secretion in the periosteal-derived cells. The ALP activity increased rapidly up to day 14, followed by decrease in activity to day 35. Runx2 was expressed strongly at day 7, followed by decreased expression at day 14, and its expression was not observed thereafter. Both VEGF 165 and VEGF 121 were expressed strongly at day 35 and 42 of culture, particularly during the later stages of differentiation. Alizarin red S-positive nodules were first observed on day 14 and then increased in number during the entire culture period. Osteocalcin and VEGF were first detected in the culture medium on day 14, and their levels increased thereafter in a time-dependent manner. These results suggest that VEGF secretion from cultured human periosteal-derived cells increases along with mineralization process of the extracellular matrix. The level of VEGF secretion from periosteal-derived cells might depend on the extent of osteoblastic differentiation.

• The korean journal of orthodontics
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• v.28 no.2 s.67
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• pp.189-201
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• 1998

The purpose of this study was to evaluate the characteristics of craniofacial skeleton on orthognathic surgical cases with skeletal Class III malocclusion. For this study, 74 students at the dental college of Chosun University volunteered as a normal occlusion group. They had well-balanced faces and good occlusions with acceptable Class I molar relationship. They had not received orthodontic treatment and had no signs or symptoms of temporomandibular joint dysfunction. 45 malocclusion patients enrolled for orthognathic surgical treatment with skeletal Class III malocclusion at the Department of Orthodontics, College of Dentistry, Chosun University. On the basis of this study. the results of this study were as follows: 1. Skeletal Class III malocclusion was largely due to the overgrowth of mandible in man and the undergrowth of maxilla in woman. 2. The mandible was antero-inferiorly overgrown by large MP-HP angle and large genial angle in orthognathic surgical cases with skeletal Class III malocclusion. And also, upper incisors were severely labioversioned, but on the other hand lower incisors were linguoversioned. 3. In female, lower-third facial height was characteristically shortened in comparison with middle-third facial height and also, lower facial throat angle was small in male.

• Restorative Dentistry and Endodontics
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• v.24 no.1
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• pp.49-54
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• 1999

Ko, Lim found some differences in the concentrations of bone resorptive cytokines, especially IL-$1{\alpha}$ and IL-$1{\beta}$ in periapical lesions and inflamed pulps. And they suppose that these differences may be due to the type of cells which produce each cytokine. The purpose of this study was to analyze the human odontogenic cysts & cystic fluid for their contents of IL-$1{\alpha}$, IL-$1{\beta}$ and TNF-$1{\alpha}$ and to compare the concentrations of each cytokine according to the cytokine producing cells. The cystic tissues used in this experiment, were obtained from periapical surgery or cyst enucleation surgery. Cystic fluid was obtained from root canal during routine endodontic therapy(n=5). Cystic tissues were subdivided into two groups, inflammatory radicular cyst group(n=15) and developmental odontogenic keratocyst group(n=3). Normal periapical tissues of extracted third molar(n=5) were also obtained to be used as control group. Each specimen was incubated in 0.5ml homogenizing buffer (0.1mol/L potassium chloride, 0.02mol/L TRIS;pH=7.6) for two hours and then homogenized with glass homogenizer. Each specimen was centrifuged in a microcentrifuge for 3 minutes, and supernatants were extracted. The concentrations of cytokines were measured with R&D ELISA kit. The data were analyzed by Mann-Whitney U test for the differences among the diseases and t test for the correlations among each cytokine. Following results were obtained ; 1. For IL-$1{\alpha}$ and IL-$1{\beta}$, all experimental groups showed significantly higher concentrations of each cytokine than the control group (p<0.05). 2. In radicular cysts, the concentrations of IL-$1{\alpha}$ were higher than IL-$1{\beta}$, but not stastically significant (p>0.05). In odontogenic keratocysts, the concentrations of IL-$1{\alpha}$ were significantly higher than IL-$1{\beta}$ (p<0.05). In cystic fluid, the concentration of IL-$1{\beta}$ was significantly higher than IL-$1{\alpha}$ (p<0.05). 3. Between odontogenic keratocysts and radicular cysts, the concentrations of IL-$1{\alpha}$ were significantly higher in odontogenic keratocysts than in radicular cysts (p<0.05). 4. For TNF-${\alpha}$, only cystic fluid group showed significantly higher concentrations than the control group (p<0.05).

• Journal of Periodontal and Implant Science
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• v.24 no.3
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• pp.661-670
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• 1994

It is well known that the application of dressings after periodontal surgery have benefits to provide the comforts to patient and to promote the healing process with action of bleeding control and temporary stabilization for the operated mobile teeth. But until recently the relationship between periodontal dressings and cells which are composed of periodontium has not been clear. The purpose of this study was to evaluate the cytotoxic effect of soluble extracts from the four different kinds of periodontal dressings, two of them were eugenol type (K.H.pack, Wondrpak) and the others were non-eugenol type (Coe-pak, Periocare), on the human gingival fibroblasts in vitro. Human gingival fibroblasts were primarily cultured from gingiva around third molar during the extraction for preventive purposes. Extracts solution were prepared with culture medium by means of imersing the consistent size of periodontal dressing made from plastic mold. Cell were inoculated into the 24 well plate with $3\;{\times}\;10^4\;cells/well$ of medium at $37\;^{\circ}C$, 100% of humidity, 5% of $CO_2$, incubator for 24 hours. After discard of the supernatant of medium, those cells were cultured with original, 1/2, 1/5, 1/10 diluted soluble extract for 24, 48 and 72 hours, and counted the number of cells using the hemocytometer at each designed time and concentration. Also, the cytotoxic effect of soluble extract was measured by Wataha's MTT assay method. In briefly, cells were inoculated and cultured into 96 well culture plate with $2\;{\times}\;10^4\;cells/well$ for 24 hours. Soluble extracts were applied to cultured cells and incubated for 48 hours at same condition. $50\;{\mu}l$ of MTT solution and DMSO were added into each well for the detection of absorbance with ELISA reader. The measured data were calculated by value of colorimetric assay for survival rate. The results were as follows ; In the case of eugenol type of dressing, original, 1/2 and 1/5 diluted extracts of K.H.pack showed very low survival rate. And original extract of Wondrpak showed strong cytotoxic effect and 1/2 diluted extract showed moderate cytotoxic effect. In the case of Non-eugenol type of dressings, only original extract of Coe-pak revealed strong cytotoxic effect and Periocare had little cytotoxic effect. It is concluded that eugenol type of dressings showed more cytotoxic effect than non-eugenol types. This study suggest that use of non-eugenol dressings after periodontal surgery is recommended.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.28 no.3
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• pp.196-204
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• 2002

For the study of its stability when the screw has been fixed after sagittal split ramus osteotomy(SSRO) of the mandible, the methods of screw arrangement are classified into two types, triangular and straight. The angles of screws to the bone surface are classified as perpendicular arrangements, the $60^{\circ}$ anterioinferior screw, known as triangular, and the most posterior screw, called straight arrangement, thus there are four types. The finite element method model has been made by using a three dimensional calculator and a supercomputer. The load directions are to the anterior teeth, premolar region, and molar region, and the bite force is 1 Kgf to each region. The distribution of stress, the von-Mises yield strength, and safety of margin refer to the total sum of transformed energy have been studied by comparison with each other. The following conclusion has been researched : 1. When shear stress is compared, in the triangular arrangement in the form of "ㄱ", the anterosuperior screw is seen at contributing to the support of the bone fragment. In the straight arrangement, substantial stress is seen to be concentrated on the most posterior angled screw. 2. When the von-Mises yield strength is compared, it seemed that the stress concentration on the angled anteroinferior screw is higher, it shows a higher possibility of fracture than any other screw. In the straight arrangement, stress appeared to be concentrated on the most posteriorly angled screw. 3. When the safety margins of the transfomed energy are compared, the energy conduction is much greater in the case of the angled screw than in the case of the perpendicular screw. The triangular arrangement in the form of "ㄱ" shows a superior clinical sign to that of the straight arrangement. Judging from the above results, when the screw fixation is made after SSRO in practical clinical cases, two screws should be inserted in the superior border of mandibular ramus and a third screw of mandibular inferior border should be inserted in the form of triangular. All screws on the bony surface should be placed perpendicularly-$90^{\circ}$ angles apparently best promote bony support and stability.

• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.4
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• pp.476-483
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• 2021

Traumatic bone cyst (TBC) is an asymptomatic lesion seen most in adolescents. TBC is found incidentally on routine panoramic examinations and appears as a relatively well-demarcated unilocular radiolucency with scalloped margins. Histological examination reveals a vacant cavity of cancellous bone usually unlined or very occasionally lined with a thin connective tissue layer. The lack of lining epithelial membrane is common histological feature. The most affected site is between the mandibular canine and third molar. The involvement of the mandibular symphysis is rare. The etiopathogenesis of the TBC is unclear. TBC is treated with surgical exploration and curettage; new bone is formed in place of the lesion within 6 - 12 months of surgery. Diagnosis of TBC prior to surgical intervention has limitations in most of the cases. Both of our patients were diagnosed through radiological examination and biopsy. Neither patient had a history of trauma. After surgery, the panoramic radiograph and CBCT were used to confirm bone healing.