• Restorative Dentistry and Endodontics
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• v.42 no.3
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• pp.176-187
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• 2017

Objectives: This study aimed to evaluate the chemical and biological properties of fast-set white mineral trioxide aggregate (FS WMTA), which was WMTA combined with calcium chloride dihydrate ($CaCl_2{\cdot}2H_2O$), compared to that of WMTA. Materials and Methods: Surface morphology, elemental, and phase analysis were examined using scanning electron microscope (SEM), energy dispersive X-ray microanalysis (EDX), and X-ray diffraction (XRD), respectively. The cytotoxicity and cell attachment properties were evaluated on human periodontal ligament fibroblasts (HPLFs) using methyl-thiazoldiphenyltetrazolium (MTT) assay and under SEM after 24 and 72 hours, respectively. Results: Results showed that the addition of $CaCl_2{\cdot}2H_2O$ to WMTA affected the surface morphology and chemical composition. Although FS WMTA exhibited a non-cytotoxic profile, the cell viability values of this combination were lesser than WMTA, and the difference was significant in 7 out of 10 concentrations at the 2 time intervals (p < 0.05). HPLFs adhered over the surface of WMTA and at the interface, after 24 hours of incubation. After 72 hours, there were increased numbers of HPLFs with prominent cytoplasmic processes. Similar findings were observed with FS WMTA, but the cells were not as confluent as with WMTA. Conclusions: The addition of $CaCl_2{\cdot}2H_2O$ to WMTA affected its chemical properties. The favorable biological profile of FS WMTA towards HPLFs may have a potential impact on its clinical application for repair of perforation defects.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.75-75
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• 2018

Commercially pure titanium (CP-Ti) and Ti-6Al-4V alloys have been widely used in implant materials such as dental and orthopedic implants due to their corrosion resistance, biocompatibility, and good mechanical properties. However, surface modification of titanium and titanium alloys is necessary to improve osseointegration between implant surface and bone. Especially, when titanium oxide nanotubes are formed on the surface of titanium alloy, cell adhesion is greatly improved. In addition, plasma electrolytic oxide (PEO) coatings have a good safety for osseointegration and can easily and quickly form coatings of uniform thickness with various pore sizes. Recently, the effects of bone element such as magnesium, zinc, strontium, silicon, and manganese for bone regeneration are researching in dental implant field. The purpose of this study was researched on the surface morphology of PEO-treated Ti-6Al-4V alloy after anodic titanium oxide treatmentusing various instruments. Ti-6Al-4V ELI disks were used as specimens for nanotube formation and PEO-treatment. The solution for the nanotube formation experiment was 1 M $H_3PO_4$ + 0.8 wt. % NaF electrolyte was used. The applied potential was 30V for 1 hours. The PEO treatment was performed after removing the nanotubes by ultrasonics for 10 minutes. The PEO treatment after removal of the nanotubes was carried out in the $Ca(CH_3)_2{\cdot}H_2O+(CH_3COO)_2Mg{\cdot}4H_2O+Mn(CH_3COO)_2{\cdot}4H_2O+Zn(CH_3CO_2)_2Zn{\cdot}2H_2O+Sr(CH_2COO)_2{\cdot}0.5H_2O+C_3H_7CaO_6P$ and $Na_2SiO_3{\cdot}9H_2O$ electrolytes. And the PEO-treatment time and potential were 3 minutes at 280V. The morphology changes of the coatings on Ti-6Al-4V alloy surface were observed using FE-SEM, EDS, XRD, AFM, and scratch tester. The morphology of PEO-treated surface in 5 ion coating solution after nanotube removal showed formation or nano-sized mesh and micro-sized pores.

• Journal of Periodontal and Implant Science
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• v.38 no.sup2
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• pp.385-394
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• 2008

Purpose: The aim of this study was to evaluate the factors affecting healing patterns of surgically created circumferential gap defects around implants in dogs. Materials and Methods: In four mongrel dogs, all mandibular premolars were extracted. After 8 weeks of healing periods, implants were submerged. According to the surface treatment, turned surface was designated as a group A and rough surface as a group B. In each dog, surgical defects on the left side were made with a customized tapered step drill and on the right with a customized paralleled drill. Groups were also divided according to the width of the coronal gaps: 1.0mm, 1.5mm, or 2.0mm. The dogs were sacrificed following 8 weeks and the specimens were analyzed histologically and histomorphometrically. Results: During the postoperative period, healing was uneventful and implants were well-maintained. As the size of the coronal gap was increased, the amount of bone-to-implant contact was decreased. The bone healing was greater in rough surface implants compared to the turned ones. About the defect morphology, tapered shape showed much bone healing and direct bone to implant contact even in the smooth surface implants. Conclusion: Healing of the circumferential defect around dental implant is influenced by the implant surface, defect width and the morphology of the defect. When using rough surface implants, circumferential gap defects within 2 mm do not need any kinds of regenerative procedures and the healing appeared to be faster in the tapered defect morphology than the paralleled one.

• The Journal of the Korean dental association
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• v.14 no.7
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• pp.591-593
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• 1976

A rare case of the third molar on the site of right maxilla has observed from a 25 years old Korean female before and after extraction. The characteristics were as following ; 1. The morphology of third molar crown had resemblance to maxillary second molar, and sizes were smaller than G.V. Black's mearsurments. 2. In occlusal view, lingual cusp was largest and distolingual cusp was not seen, and decayed to the extent of degreei. 3. Numbers of root were 5 and they were not fused.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2011.05a
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• pp.102-102
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• 2011

• The korean journal of orthodontics
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• v.46 no.6
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• pp.345-355
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• 2016

Objective: The purpose of this study was to determine whether predicting maturation of the midpalatal suture is possible by classifying its morphology on cone-beam computed tomography (CBCT) images and to investigate relationships with other developmental age indices. Methods: The morphology of the midpalatal suture was assessed by using CBCT images of 99 patients. Axial plane images of the midpalatal suture were classified into five stages according to the classification scheme. To make the assessment more accurate, the morphology and fusion of the midpalatal suture were additionally investigated on coronal cross-sectional planar images and volume-rendered images. Bone age was evaluated using the hand and wrist method (HWM) and cervical vertebrae method (CVM); dental age (Hellman's index), sex, and chronological age were also assessed. To evaluate relationships among variables, Spearman's rho rank test was performed along with crosstabs using contingency coefficients. Results: The HWM and CVM showed strong correlations with the maturation stage of the midpalatal suture, while other indices showed relatively weak correlations (p < 0.01). Through crosstabs, the HWM and CVM showed high association values with CBCT stage; the HWM demonstrated slightly higher values (p < 0.0001). Based on the HWM, the midpalatal suture was not fused until stage 6 in both sexes. Conclusions: Among developmental age indices, the HWM and CVM showed strong correlations and high associations, suggesting that they can be useful in assessing maturation of the midpalatal suture.

• The Journal of the Korean dental association
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• v.58 no.9
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• pp.546-555
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• 2020

Allergic rhinitis is a specific IgE mediated inflammatory disease of the nasal mucosa, characterized by symptoms such as rhinorrhea, nasal congestion, nasal obstruction, nasal and eye itching, and sneezing. The prevalence of allergic rhinitis varies according to country, age, and surveying methods, but it seems to increase worldwide, also in Korea. Prolonged mouth breathing caused by allergic rhinitis can produce muscular and postural alterations, causing alterations on the morphology, position, growth direction of the jaws, and malocclusion. Also, mouth breathing leads to dryness of the mouth, causing various oral diseases; gingivitis, halitosis, inflammation of tonsil, increased risk of dental caries and dental erosion. In dental clinic, using rapid maxillary expansion to persistent allergic rhinitis patients with narrow maxilla can enlarge maxillary dental arch and nasal cavity anatomy, improving nasal breathing and reducing nasal cavity resistance. However, it is desirable to use along with otolaryngologic treatment. Dentists should be aware of the characteristics of allergic rhinitis and its effects on patients, and consider when planning dental treatment.

• The Journal of the Korean dental association
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• v.52 no.9
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• pp.541-549
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• 2014

The restorative treatment using titanium implants has become a standard procedures in everyday clinical practice. However, there are several concerns about the use of titanium as a materials. Above all, the grayish metal color provokes esthetic problems when the soft tissue around the implants is not optimal. Recently, zirconia has been emerging as an alternative to titanium due to its white color and superior physicochemical properties. In this paper, the current findings about zirconia implants was reviewed based on the results from animal and clinical experiments. In addition, the immediate implantation protocols using the natural tooth form zirconia implants was introduced as a novel procedures and future perspectives were discussed.

• The Journal of the Korean dental association
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• v.54 no.5
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• pp.328-341
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• 2016

An overall reduction in the horizontal and vertical dimensions occurs following tooth extraction and the resorption of the buccal part of the ridge is more pronounced than the lingual part. Thus, the resulting morphology of the healed alveolar ridge is often presenting with a discrepancy in bone height between the buccal and lingual aspects of the ridge. The implant with a sloped marginal configuration that is designed to match the sloped contour of the alveolar ridge provides the opportunity to maintain the buccal-lingual bone discrepancy and soft tissue around the implant. This paper introduces the OsseoSpeed TX Profile implants with sloped marginal configuration and explains the characteristics and clinical meanings of those implants.

• Korean Journal of Materials Research
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• v.15 no.3
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• pp.209-215
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• 2005

Titanium dioxide films $(TiO_2)$ doped cobalt transition metal were prepared on titanium metal by water spray pyrolysis technique. Micro-morphology, crystalline structure, chemical composition and binding state of sample groups were evaluated using field emission scanning microscope(FE-SEM), X-ray diffractometer(XRD), Raman spectrometer, X-ray photoelectron spectrometer(XPS). $TiO_2$ films of rutile structure were predominately formed on all sample groups and $Ti_2O_3$ oxide was coexisted on the surface of cobalt doped-sample groups. The optical absorption peaks measured by using UV-VIS-NIR spectrophotometer were observed at specific wavelength region in sample groups doped cobalt ion. This result could be analyzed by introducing crystal field theory.