• Journal of Korean Neurosurgical Society
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• v.57 no.4
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• pp.242-249
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• 2015

Objective : The timing of cranioplasty and method of bone flap storage are known risk factors of non-union and resorption of bone flaps. In this animal experimental study, we evaluated the efficacy of cranioplasty using frozen autologous bone flap, and examined whether the timing of cranioplasty after craniectomy affects bone fusion and new bone formation. Methods : Total 8 rabbits (male, older than 16 weeks) were divided into two groups of early cranioplasty group (EG, 4 rabbits) and delayed cranioplasty group (DG, 4 rabbits). The rabbits of each group were performed cranioplasty via frozen autologous bone flaps 4 weeks (EG) and 8 weeks (DG) after craniectomy. In order to obtain control data, the cranioplasty immediate after craniectomy were made on the contralateral cranial bone of the rabbits (control group, CG). The bone fusion and new bone formation were evaluated by micro-CT scan and histological examination 8 weeks after cranioplasty on both groups. Results : In the micro-CT scans, the mean values of the volume and the surface of new bone were $50.13{\pm}7.18mm^3$ and $706.23{\pm}77.26mm^2$ in EG, $53.78{\pm}10.86mm^3$ and $726.60{\pm}170.99mm^2$ in DG, and $31.51{\pm}12.84mm^3$ and $436.65{\pm}132.24mm^2$ in CG. In the statistical results, significant differences were shown between EG and CG and between DG and CG (volume : p=0.028 and surface : p=0.008). The histological results confirmed new bone formation in all rabbits. Conclusion : We observed new bone formation on all the frozen autologous bone flaps that was stored within 8 weeks. The timing of cranioplasty may showed no difference of degree of new bone formation. Not only the healing period after cranioplasty but the time interval from craniectomy to cranioplasty could affect the new bone formation.

• Journal of Periodontal and Implant Science
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• v.47 no.5
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• pp.328-338
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• 2017

Purpose: Chronic periodontitis is an inflammatory disease induced by pathogenic bacterial accumulation. A novel index, the periodontal inflamed surface area (PISA), represents the sum of the periodontal pocket depth of bleeding on probing (BOP)-positive sites. It is advantageous for data processing and analysis because it can be treated as a continuous variable to quantify periodontal inflammation. In the present study, we evaluated correlations between PISA and periodontal classifications, and examined PISA as an index integrating the discrete conventional periodontal indexes. Methods: This study was a cross-sectional subgroup analysis of data from a prospective cohort study investigating the association between chronic periodontitis and the clinical features of ankylosing spondylitis. Data from 84 patients without systemic diseases (the control group in the previous study) were analyzed in the present study. Results: PISA values were positively correlated with conventional periodontal classifications (Spearman correlation coefficient=0.52; P<0.01) and with periodontal indexes, such as BOP and the plaque index (PI) (r=0.94; P<0.01 and r=0.60; P<0.01, respectively; Pearson correlation test). Porphyromonas gingivalis expression and the presence of serum P. gingivalis antibodies were significant factors affecting PISA values in a simple linear regression analysis, together with periodontal classification, PI, bleeding index, and smoking, but not in the multivariate analysis. In the multivariate linear regression analysis, PISA values were positively correlated with the quantity of current smoking, PI, and severity of periodontal disease. Conclusions: PISA integrates multiple periodontal indexes, such as probing pocket depth, BOP, and PI into a numerical variable. PISA is advantageous for quantifying periodontal inflammation and plaque accumulation.

• The Korean Journal of Pain
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• v.31 no.4
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• pp.289-295
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• 2018

Background: The intraarticular (IA) injection has become popular for the management of the osteoarthritic knee without an effusion. The success rate of IA injection would be better if it was able to be visually confirmed. We hypothesized that an anterolateral approach, which targets the synovial membrane of the lateral condyle using ultrasound, would provide an equivalent alternative to the anterolateral approach, targeting the synovial membrane of the medial condyle for IA injection of the knee. Methods: A total of 96 knees with osteoarthritis were randomized placed into the two groups, which were group I (anterolateral approach to the medial condyle) and group II (anterolateral approach to the lateral condyle). The primary outcome was to compare the success rate of the two methods of IA injection. The required length of the needle for injection was also measured and compared. Pain intensity was assessed using the Numeric Rating Scale in order to evaluate the success of injection. Results: There were no significant differences in the success rate between both groups. The success rate of group I and group II were 87.8% (95%, CI 78.7-97.0) and 91.5% (95%, CI 83.6-99.5), respectively (P = 0.549). The needle depth was $5.0{\pm}0.8$ (3.0 to 6.1 cm) in group I, and $3.0{\pm}0.8$ (1.5 to 5 cm) in group II (P < 0.001). Conclusions: The anterolateral approach to the lateral femoral condyle, using ultrasound, is an alternative method to the approach targeting the medial femoral condyle, using shorter needle.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.8
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• pp.3495-3501
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• 2014

Melanoma-associated antigen (MAGE) family genes have been considered as potentially promising targets for anticancer immunotherapy. MAGED4 was originally identified as a glioma-specific antigen. Current knowledge about MAGED4 expression in glioma is only based on mRNA analysis and MAGED4 protein expression has not been elucidated. In the present study, we investigated this point and found that MAGED4 mRNA and protein were absent or very lowly expressed in various normal tissues and glioma cell line SHG44, but overexpressed in glioma cell lines A172,U251,U87-MG as well as glioma tissues, with significant heterogeneity. Furthermore, MAGED4 protein expression was positively correlated with the glioma type and grade. We also found that the expression of MAGED4 inversely correlated with the overall methylation status of the MAGED4 promoter CpG island. Furthermore, when SHG44 and A172 with higher methylation were treated with the DNA demethylating agent 5-aza-2'-deoxycytidine (5-AZA-CdR) reactivation of MAGED4 mRNA was mediated by significant demethylation in SHG44 instead of A172. However, 5-AZA-CdR treatment had no effect on MAGED4 protein in both SHG44 and A172 cells. In conclusion, MAGED4 is frequently and highly expressed in glioma and is partly regulated by DNA methylation. The results suggest that MAGED4 might be a promising target for glioma immunotherapy combined with 5-AZA-CdR to enhance its expression and eliminate intratumor heterogeneity.

• Journal of Biosystems Engineering
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• v.39 no.2
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• pp.122-133
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• 2014

Purpose: This study was to develop an effective process for fabricating biocompatible calcium phosphate powders (CPPs) using horse bones, and to investigate the characteristics of them. Methods: The characteristics of horse bone powders (HBPs) were investigated according to the different osseous tissue types (compact bone and cancellous bone), bone types (spine and tibia), pretreatment methods (cold water, $H_2O_2$, and hot water), sintering time (4, 8 and 12h), and sintering temperature (600, 900, 1100 and $1300^{\circ}C$). In addition, the grinding methods were compared based on the wet grinding (ball mill) and dry grinding (blade grinder) method to make it as powders. Finally, their cytotoxicity and cell viability were checked. Results: Regardless of the types of osseous tissues and bones, HBPs were well fabricated as biocompatible CPPs. It was also found that the pretreatment methods did not influence on the resultants, showing well-fabricated HBPs. Considering the processing time, the hot water method was the most suitable compared to other pretreatment methods. Further, 12h-sintering time was sufficient to remove residual organic compounds. The sintering temperatures greatly affected the properties of bone powders fabricated. The x-ray diffraction (XRD) peak of horse bone sintered at $600^{\circ}C$ was most closed to that of hydroxyapatite (HA). Our bioactivity study demonstrated that the HBPs fabricated by sintering horse bones at $1300^{\circ}C$ showed the best performance in terms of cell viability whereas the HBPs $1100^{\circ}C$ showed the cytotoxicity. Conclusions: Using various types of horse bone tissues, biocompatible CPPs were successfully developed. We conclude that the HBPs may have a great potential as biomaterials for various biological applications including bone tissue engineering.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.12
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• pp.5049-5053
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• 2014

Background: To investigate the expression of CD44v3 and vascular endothelial growth factor-C (VEGF-C) and their relationship with lymph node metastasis in squamous cell carcinomas (SCC) of the uterine cervix. Materials and Methods: Expression of CD44v3 and VEGF-C was analyzed in 109 cases of cervical SCC by immunohistochemistry (IHC). The relationship was analyzed between expression and the patient age, histological differentiation, formation of tumor emboli in lymphoid vessels, lymph node metastasis, FIGO staging, and TNM classification. Results: Expression rates for both CD44v3 and VEGF-C were 43.1% in cervical SCC. The cells with positive immunohistochemical staining of CD44v3 were distributed mainly around the keratin pearls in well differentiated carcinomas, but distributed diffusely in the moderately and poorly differentiated lesions. VEGF-C was found stained positively in most of the tumor cells. There were differences in expression between normal epithelium and atypical hyperplasia as well as carcinoma. Both CD44v3 and VEGF-C were found to be associated positively with lymph node metastasis and TNM classification (both p=0.000). Neither CD44v3 nor VEGF-C was found to be associated with patient age, histological differentiation, formation of tumor emboli in lymphoid vessels and FIGO staging. CD44v3 was found to be associated with VEGF-C positively (p=0.000). Conclusions: Abnormal expression of CD44v3 and VEGF-C is associated closely with the lymph node metastasis in cervical SCC, and these agents may cooperate in carcinogenesis and development of metastatic lesions.

• Molecules and Cells
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• v.40 no.6
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• pp.386-392
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• 2017

Periodontal ligament stem cells (PDLSCs) are multipotent stem cells derived from periodontium and have mesenchymal stem cell (MSC)-like characteristics. Recently, the perivascular region was recognized as the developmental origin of MSCs, which suggests the in vivo angiogenic potential of PDLSCs. In this study, we investigated whether PDLSCs could be a potential source of perivascular cells, which could contribute to in vivo angiogenesis. PDLSCs exhibited typical MSC-like characteristics such as the expression pattern of surface markers (CD29, CD44, CD73, and CD105) and differentiation potentials (osteogenic and adipogenic differentiation). Moreover, PDLSCs expressed perivascular cell markers such as NG2, ${\alpha}-smooth$ muscle actin, platelet-derived growth factor receptor ${\beta}$, and CD146. We conducted an in vivo Matrigel plug assay to confirm the in vivo angiogenic potential of PDLSCs. We could not observe significant vessel-like structures with PDLSCs alone or human umbilical vein endothelial cells (HUVECs) alone at day 7 after injection. However, when PDLSCs and HUVECs were co-injected, there were vessel-like structures containing red blood cells in the lumens, which suggested that anastomosis occurred between newly formed vessels and host circulatory system. To block the $SDF-1{\alpha}$ and CXCR4 axis between PDLSCs and HUVECs, AMD3100, a CXCR4 antagonist, was added into the Matrigel plug. After day 3 and day 7 after injection, there were no significant vessel-like structures. In conclusion, we demonstrated the perivascular characteristics of PDLSCs and their contribution to in vivo angiogenesis, which might imply potential application of PDLSCs into the neovascularization of tissue engineering and vascular diseases.

• Restorative Dentistry and Endodontics
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• v.19 no.1
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• pp.135-147
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• 1994

This study was conducted to evaluate whether the fatigue toughness of visible light cured composite resins could be improved and how much percentage of polymerzation shrinkage could be affected by additional heat treatment. 7 materials were investigated for this study: P-50, Lite-fil CR inlay, Pekafil, Clearfil CR inlay, Clearfil photo posterior, Z -100 and Progress. Diametral tensile strengths and linear shrinkages of composite resins were taken under visible light cured and additional post-cure heated condition and compared each other. A fatigue toughness of above materials was evaluated by measuring diametral tensile strength after they were repeatedly loaded with 120kgf/$cm^2$ up to 3000 cycles. The results obtained were as follows : 1. When composite resins were cured just by visible light, Lite fil CR inlay, Z -100 and Progress showed respectively higher diametral tensile strength than the other materials. Clearfil CR inlay, Clearfil photo posterior and Progress exhibited strong fatigue toughness compared to P-50 and Pekafil. 2. Post-cure heat treated composite resins had higher diametral tensile strengths than visible light cured composite resins at fatigue toughness test as well as no fatigue toughness test. 3. When Composite resins were additionally polymerized by post-cure heat treatment, P-50 showed weak fatigue toughness, on the contrary, Clearfil CR inlay, Z-100, Progress showed strong one. 4. When composite resins were cured just by visible light, percentage of polymerization linear shrinkage was the lowerest in Clearfil CR inlay, followed by, in ascending order, Clearfil photo posterior, Lite-fil CR inlay, Progress, Pekafil, P-50, and Z-100. In the case of post- cure heat treated composite resins, percentage of linear shrinkage was the lowest in Clearfil photo posterior, followed by, in ascending order, Lite-til CR inlay, Clearfil CR inlay, Progress, P-50, Pekafil and Z-100. 5. Percentage of polymerization linear shrinkage was greater in the post-cure heat treated composite resins than in the visible light cured composite resins and linear shrinkage increased significantly in Pekafil, Clearfil CR inlay, and Clearfil photo posterior between at the visible light cured and at the post-cure heat treated condition. The above results is saying that additional post-cure heat treatment on the composite resins for posterior restoration is able to affect on improvement of strength and fatigue toughness and lead to increase polymerization of composite resins.

• Journal of Korean society of Dental Hygiene
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• v.11 no.1
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• pp.127-136
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• 2011

Objectives : The writer aimed to examine the dynamic aspect on damage and to be conducive to the swift cure according to right treatment to educate prevention of injury through surveying on the number of the damaged teeth given injury, tooth kind, type in damage, place and cause for being damaged, frequency by month and by time level, and location of the damaged tooth. Methods : Targeting 343 teeth of receiving injury in 201 patients who visited the department of pediatric dentistry, the department of preservation, and the oral and maxillofacial surgery in a dental hospital in Cheonan city from April 2007 to April 2009, by having the dental injury as the main reason, the following conclusions were obtained. Results : 1. Deciduous teeth were indicated to be the highest in imperfect luxation with 60.7%, and were indicated to be in order of crown fracture with 25.5%, root fracture with 12.4%, and perfect luxation with 1.4%. The permanent teeth were indicated to be the highest in crown with 58.1%, and were indicated to be in order of imperfect luxation with 27.3%, root fracture with 13.1%, and perfect luxation with 1.5%(p<0.001). 2. In case of deciduous teeth for a place with damage, the home was indicated to be the highest with 31.7%. The permanent teeth were indicated to be the highest(p<0.001) in the road and stairs with 40.4%. As to a cause for damage, both deciduous and permanent teeth were indicated to be the highest(p<0.001) in a cause for falling with 53.1% and 30.8%, respectively. 3. As for a treatment method, in case of deciduous teeth, the close observation was indicated to be the highest with 46.9%. In permanent teeth, the resin restoration was indicated to be the highest(p<0.001) with 22.2%. Dental injuries in deciduous teeth and permanent teeth are showing diverse aspects. Conclusions : It is important to arrange guidelines on cure of the damaged teeth by injury through continuing a dynamic research on these aspects. Also, the damage in deciduous teeth may have direct and indirect influence upon growth in successional permanent teeth. Thus, through careful treatment, the injury needs to be minimized. It is considered to be likely necessary for a right coping method when injury occurs, and above all, for enough prior education so that injury cannot occur.

• Journal of Korean Academy of Dental Administration
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• v.9 no.1
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• pp.14-24
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• 2021

Dentists and dental hygienists are major collaborators, as expressed by the concept of "Four-handed dentistry." Dentists are guaranteed their legal duties and rights in accordance with the Medical Act, whereas dental hygienists are currently stipulated in the scope of their legal duties under the Act on Medical Technicians. However, there is a difference between the actual work and the legal work performed by dental hygienists; therefore, the work is dependent on many legal controversies and authoritative interpretations. The purpose of this study is, first, to develop a reliable questionnaire tool regarding the actual work performed by dental hygienists in dental hospitals and clinics, and second, to examine the awareness of the appropriateness of legal work based on the developed questionnaire. The target subjects of the survey were dental hygienists and dentists, and the dental hygienists were those who worked in dental hospitals and clinics as license reporters of the Korean Dental Hygienists Association. A total of 1,294 dental hygienists and 39 dentists were included in the final analysis. In the dental hygienist group, 19 items received the response "appropriate for legal work" in over 90% of cases, accounting for 25% of the total 76 items. In addition, in a total of 31 items, more than 80% of the responses were appropriate for legal work. Among them, the highest was 'Scailing' (97.7%), followed by "Extraoral-Panorama" (97.1%). In the dentist group, 10 out of 76 items showed over 90% adequacy for legal work, and among them, "instrument cleaning and sterilization" was the highest at 100%. It was followed by "Intraoral radiography," "Scailing," and "Toothpick method, TPM" with 97.4%. In the case of dentists, 28 out of a total of 76 items showed an appropriateness of more than 80% for legal work. This study comprehensively investigated the actual work of dental hygienists in line with timely and appropriate social issues and provided reliable statistics in evidence-based dentistry.