• Journal of Korean Neurosurgical Society
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• v.56 no.5
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• pp.383-389
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• 2014

Objective : Neural tissue transplantation has been a promising strategy for the treatment of Parkinson's disease (PD). However, transplantation has the disadvantages of low-cell survival and/or development of dyskinesia. Transplantation of cell aggregates has the potential to overcome these problems, because the cells can extend their axons into the host brain and establish synaptic connections with host neurons. In this present study, aggregates of human brain-derived neural stem cells (HB-NSC) were transplanted into a PD animal model and compared to previous report on transplantation of single-cell suspensions. Methods : Rats received an injection of 6-OHDA into the right medial forebrain bundle to generate the PD model and followed by injections of PBS only, or HB-NSC aggregates in PBS into the ipsilateral striatum. Behavioral tests, multitracer (2-deoxy-2-[$^{18}F$]-fluoro-D-glucose ([$^{18}F$]-FDG) and [$^{18}F$]-N-(3-fluoropropyl)-2-carbomethoxy-3-(4-iodophenyl)nortropane ([$^{18}F$]-FP-CIT) microPET scans, as well as immunohistochemical (IHC) and immunofluorescent (IF) staining were conducted to evaluate the results. Results : The stepping test showed significant improvement of contralateral forelimb control in the HB-NSC group from 6-10 weeks compared to the control group (p<0.05). [$^{18}F$]-FP-CIT microPET at 10 weeks posttransplantation demonstrated a significant increase in uptake in the HB-NSC group compared to pretransplantation (p<0.05). In IHC and IF staining, tyrosine hydroxylase and human ${\beta}2$ microglobulin (a human cell marker) positive cells were visualized at the transplant site. Conclusion : These results suggest that the HB-NSC aggregates can survive in the striatum and exert therapeutic effects in a PD model by secreting dopamine.

• Journal of Dental Rehabilitation and Applied Science
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• v.29 no.4
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• pp.377-383
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• 2013

This study examined the radiopacity of eight contemporary luting cements by direct digital radiography. Five disc-shaped specimens ($5mm{\times}1mm$) were prepared for each material tested (BisCem, Clearfil SA Luting, Duolink, Maxcem Elite, Multilink Speed, Panavia F 2.0, RelyX Unicem Clicker, V-link). The specimens were radiographed using a Kodak CS 7600 image plate (Carestream Health, Inc., Rochester, NY, USA) and an aluminum step wedge with a range of thicknesses (1.5 to 16.5 mm in 1.5 mm increments) and a 1 mm tooth used as a reference. A dental X-ray machine Kodak 2200 Intraoral X-ray System (Carestream Health, Inc., Rochester, NY, USA), operating at 70 kVp, 4 mA, 0.156 s and a source-to-sample distance of 30 cm, was used. According to international standards, the radiopacity of the specimens was compared with that of an aluminum step wedge using NIH ImageJ software (available at http://rsb.info.nih.gov/ij/).The data was analyzed by ANOVA and a Tukey's post hoc test. Maxcem Elite (5.66) showed the highest radiopacity of all materials, followed in order by Multilink Speed (3.87) and V-link (2.83). The radiopacity of Clearfil SA Luting (1.35), BisCem (1.33), Panavia F 2.0 (1.29) and Duolink (1.10) were between enamel (1.79) and dentin (0.19). RelyX Unicem Clicker (0.71) showed the lowest radiopacity, which was higher than that of dentin. All materials showed a radiopacity above the minimum recommended by the International Organization for Standardization and the American National Standards/American Dental Association with the exception of RelyX Unicem Clicker.

• Implantology
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• v.22 no.4
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• pp.220-235
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• 2018

Sinus lift procedure is frequently required for the maxillary molar implant placement. Previous studies have demonstrated alveolar ridge preservation (ARP) can maintain the dimensions of ridge height and width. However, there is a lack of studies which evaluated the effect of ARP to avoid sinus lift procedure. Purpose of this study is to describe a method reducing the need of sinus lift surgery by ARP in maxillary molar areas and to assess the feasibility clinically, radiologically and histologically. Ten maxillary molars in ten patients had severe vertical bone resorption with minimal residual bone height. They were considered having the high possibility of the necessity of sinus lift procedure for dental implant after the extraction. After extraction, open healing ARP with deproteinized bovine bone mineral mixed with 10% collagen and resorbable collagen membranes was performed. After sufficient healing, dental implants were placed, and evaluated clinically and radiologically. Histological observation was conducted just before the implantation in one patient. Implants were successfully placed without sinus lift in all ten cases. All the implants were restored with no sign of complications, and patients are now in a close follow-up up to 20 months post-loading. Histological observation showed minimal inflammatory reaction and newly formed bone was substantially noted. The ARP technique has successfully avoided the sinus lift surgeries. It appears that this procedure may improve the simplicity of the clinical process for the clinicians and reduce the discomfort of patients.

• The korean journal of orthodontics
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• v.38 no.3
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• pp.159-174
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• 2008

Objective: The purpose of this study was to investigate whether cortical punching could stimulate the expression of OPG, RANK, and RANKL during tooth movement by immunohistochemistry. Methods: 34 sprague-dawley rats (15 weeks old) were allocated into 3 groups: TMC group (experimental group; Tooth Movement with Corticotomy, n = 16), TM group (control group; Tooth Movement only group, n = 16), and non-treatment group (n = 2). 20 gm of orthodontic force was applied to rat incisors by inserting elastic bands. The duration of force application was 1, 4, 7 and 14 days. A microscrew (diameter 1.2 mm) was used for cortical punching of the palatal side of the upper incisors in the TMC group. Results: Distributions of OPG, RANK, and RANKL were evaluated by immunohistochemistry. OPG, RANK and RANKL were observed on experimental and control groups. On the compression side, the degree of the expression of OPG decreased in both groups. The expression of RANK was most prominent in the experimental group of day 4. The expression of RANKL was most intensive and extensive in the experimental group of day 7. However, the expression of OPG was decreased in the experimental and control groups compared to the non treatment group. The expression of OPG, RANK and RANKL after force application were decreased at day 14. Conclusions: These findings suggested that cortical punching might stimulate remodeling of alveolar bone during a 2 week period of tooth movement without any pathologic change.

• Korean Journal of Biological Psychiatry
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• v.20 no.2
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• pp.54-60
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• 2013

Objectives The purpose of this study is to find the influential clinical and physical characteristics which affect apnea-hypopnea index (AHI) in suspected obstructive sleep apnea (OSA) patients. Methods We evaluated the comprehensive factors including sleep related symptoms, clinical scales, medical history, substance use, and anthropometric data of the 119 participants who complained of the symptoms of OSA. All the participants underwent attended-full night laboratory polysomnography. The correlation and multiple regression analysis were conducted to find the influential and predictive factors of AHI. Results A multiple linear regression model 1 showed that higher AHI was associated with higher body mass index (BMI)(p < 0.001) and higher frequency of observed apnea (p = 0.002). In multiple linear regression model 2, AHI was associated with higher BMI (p < 0.001) and loudness of snoring (p = 0.018). Conclusions The present preliminary results suggest that BMI and observed apnea are most influential factors that affect AHI in suspected OSA patients. In the future study we will design the prediction formula for the OSA and AHI, which is useful in the clinical medical field.

• Journal of Dental Rehabilitation and Applied Science
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• v.25 no.2
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• pp.157-169
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• 2009

The aim of this study was to evaluate effect of implant abutment screw coating treatment on joint stability, investigating mechanical properties of these. For this study used $ExFeel^{(R)}$ external hexed implant system and $15mm{\times}1mm$ discs. Experimental group was $1{\mu}m$ TiN, TiCN, TiC coated abutment screws and discs. To know mechanical property, i evaluated adhesion strength, surface hardness, using disc, corrosion test using screw. The results were as follows : rotation angle of coated screws increased than that of non-coated screw because of lower friction coefficient, especially TiC coated screw group had the largest value, but removal torque decreased in all coated screws (p<0.05). Torque loss before and after fatigue test was the smallest in TiC-coated screws, and the largest in non-coated screws (p<0.05), and there was no statistically significant difference between dry condition and wet condition of screws because of higher surface hardness and lower friction coefficient. From the above results, TiN, TiCN, TiC coating group had high abrasion resistance, especially TiC coated group which had low torque-consuming, high rotation angle as low friction coefficient will be considered to influence on implant abutment screw joint stability positively.

• The Journal of Advanced Prosthodontics
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• v.8 no.2
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• pp.94-100
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• 2016

PURPOSE. To evaluate the effects of hydrogen peroxide pretreatment and heat activation of silane on the shear bond strength of fiber-reinforced composite posts to resin cement. MATERIALS AND METHODS. The specimens were prepared to evaluate the bond strength of epoxy resin-based fiber posts (D.T. Light-Post) to dual-curing resin cement (RelyX U200). The specimens were divided into four groups (n=18) according to different surface treatments: group 1, no treatment; group 2, silanization; group 3, silanization after hydrogen peroxide etching; group 4, silanization with warm drying at $80^{\circ}C$ after hydrogen peroxide etching. After storage of the specimens in distilled water at $37^{\circ}C$ for 24 hours, the shear bond strength (in MPa) between the fiber post and resin cement was measured using a universal testing machine. The fractured surface of the fiber post was examined using scanning electron microscopy. Data were analyzed using one-way ANOVA and post-hoc analysis with Tukey's HSD test (${\alpha}=0.05$). RESULTS. Silanization of the fiber post (Group 2) significantly increased the bond strength in comparison with the non treated control (Group 1) (P<.05). Heat drying after silanization also significantly increased the bond strength (Group 3 and 4) (P<.05). However, no effect was determined for hydrogen peroxide etching before applying silane agent (Group 2 and 3) (P>.05). CONCLUSION. Fiber post silanization and subsequent heat treatment ($80^{\circ}C$) with warm air blower can be beneficial in clinical post cementation. However, hydrogen peroxide etching prior to silanization was not effective in this study.

• Archives of Plastic Surgery
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• v.37 no.5
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• pp.691-694
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• 2010

Purpose: Central giant cell granuloma is a rare, benign giant cell tumor which commonly develops in areas near the teeth. It accounts for approximately less than 7% of benign tumors of the mandible. Clinically, central giant cell granuloma is classifed into aggressive and non-aggressive type, and usually requires surgical treatment. There has been no report of central giant cell granuloma in plastic surgery field of the country, and we report a case with a brief review of the diagnosis and treatment of the disease. Methods: A 23-year-old male presented with a hard, non-tender, growing mass with the size of $4.0{\times}3.0\;cm$ on mandible for several months. Computed tomography scan showed a solid mass within thinned outer cortex on mandible. The thinned outer cortex was excised with the mass and the inner cortex was partially removed burring. After the tumor removal, mandible was fixed by reconstruction plate. Results: Pathologic report showed numerous large multinucleated giant cells, diffusely distributed in a background of ovoid-to-spindle-shaped mononuclear cells. There was no evidence of recurrence after 1 year follow up. Bony defect was regenerated and we removed the reconstruction plate. Conclusion: Removal of central giant cell granuloma results in defect of outer cortex, which can be reconstructed by using reconstruction plate, autologous bone graft or bone cement. We used reconstruction plate as a conservative method to induce secondary healing of the outer cortical defect area, which resulted in normal mastication and occlusion with no recurrence.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.3
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• pp.480-487
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• 2001

In children and adolescents, oral and maxillofacial trauma is one of the most common causes of dental and periodontal damage, which often induces crown fracture of the permanent anterior teeth. Frequently, these traumatized teeth lose their vitality, and require routine endodontic treatment if their root apices are closed. However if their apices are not fully closed, further root formation should be promoted by apexification or apexogenesis. Calcium hydroxide is a biocompatible & bacteriostatic material, and is widely used for apexification. However it has several disadvantages which include the need for multiple visits and patient cooperation, low strength and technical sensitivity in a broad apex. In one-visit apexification using IRM or SuperEBA, patient's visits can be minimized. However, their biocompatibility is questionable. Mineral trioxide aggregate(MTA) is a relatively new material. It is considered biocompatible with periapical hard tissue and has good marginal sealing ability. MTA is also known to help facillitate the growth of the cementum around it. In this case report, apexification with MTA was attempted on traumatized maxillary central incisors with immature root apices, and favorable clinical results were achieved.

• The korean journal of orthodontics
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• v.38 no.2
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• pp.121-132
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• 2008

Objective: The purpose of this study was to evaluate the upper airway dimensional change according to maxillary superior movement after orthognathic surgery and to identify the relationship between the amount of maxillary movement and upper airway dimensional changes. Methods: The samples consisted of 24 adult patients (9 males and 15 females) who had a skeletal discrepancy and had received presurgical orthodontic treatment. They underwent Le Fort I superior impaction osteotomy and mandibular setback surgery. Cephalometric x-rays were taken at 3 stages - T0 (before orthognathic surgery), T1 (just or within 2 weeks after orthognathic surgery), T2 (6 months after surgery) Results: 1, Pharyngeal airway space (PAS (R)-nasopharynx) was decreased after surgery (T1) but recovered at 6 months after surgery; 2, Pharyngeal airway space (PAS (NL)-palatal plane) was increased after surgery and at 6 months after surgery; 3, Pharyngeal airway space (PAS (OL)-occlusal plane) was increased at T1 and was decreased at T2; 4, Soft palate thickness was increased at T1 but it became the same or thinner at T2; 5, There is no statistically significant relation between the amount of maxillary superior movement and pharyngeal airway space. Conclusions: These findings suggested that the maxillary superior movement of about an average of $4.40{\pm}1.14 mm$ did not affect upper pharyngeal airway space changes.