• The korean journal of orthodontics
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• v.34 no.6 s.107
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• pp.514-525
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• 2004

The purpose of this study was to evaluate the correlation between nicotine and the activity of bone forming cell. MG63 osteoblast-like cells were used for this study. Several factors were examined including the proliferation of cell, alkaline phosphatase activity, the formation of osteocalcin and osteoprotegerin. and the synthesis of its mRNA. MG63 osteoblast-like cells were incubated for 1, 2, 3 and 6 days with nicotine added to the culture medium in 1.0 ${\mu}M$, 1.0mM, 2.5mM, 5.0mM, 7.5mM, and 10.0mM concentrations. The proliferation of MG63 osteoblast-like cells was temporarily activated at the low nicotine concentrations. At high concentrations (>5.0 mM), however. it was suppressed. Alkaline phosphatase activity was suppressed in a dose-dependent manner as the concentration of nicotine increased. Osteocalcin decreased in a dose-dependent manner at high nicotine concentrations of more than 7.5mM and the same result was show when the osteoblasts were treated with low concentrations for longer than 3 days. There was a difference in the influence of nicotine on the synthesis of osteocalcin mRNA and formation of osteocalcin itself at 1 and 3 days. Generally, osteoprotegrin notably declined in all experimental groups. However, the level of its mRNA increased at high nicotine concentrations of more than 7.5mM after 3 days and more than 5.0mM after 6days.

• The korean journal of orthodontics
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• v.36 no.3 s.116
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• pp.218-227
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• 2006

Although the submentovertex radiograph and surface EMG are not often used due to the difficulty of interpretation, they are accepted as useful diagnostic and analytic aids for skeletal asymmetry. There have been reports which state that they were also useful for the evaluation of vertical skeletal relations. The purpose of this study was to evaluate the correlations between EMG data, measurements from submentovertex radiographs, facial types and facial asymmetry following examination of 60 asymmetric patients. The radiographic corpus length were greater in the nonaffected sides (p<0.001), gonion to interspinosum axis were greater in the affected sides and the mandibular condyle and gonion were located more anteriorly in the non-affected sides than in the affected sides but not significant (p=0.07). The activity of the anterior temporal muscle in rest position was higher in the affected sides than in the non-affected sides (p<0.01). The activity of the masseter muscle at maximum clenching was found to be nonsignificant but it was higher in the affected sides than in the non-affected sides (p=0.09). There was positive correlation between facial index and the intercondylar axes angle (p<0.01). There was positive correlation between masseter muscle activity in maximum occlusion and facial index in the affected and non-affected sides (p<0.05). The results demonstrate that the submentovertex radiograph and EMG can provide useful information for the evaluation of horizontal and vertical skeletal relations.

• The korean journal of orthodontics
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• v.39 no.6
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• pp.383-392
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• 2009

Objective: The purpose of this study was to evaluate the efficacy of a slim bristled toothbrush compared with a V-shaped orthodontic toothbrush in patients with fixed orthodontic appliances. Methods: Thirty four orthodontic patients receiving edgewise treatment were randomly assigned to two groups, a slim bristled toothbrush (Nano silver slim care) and a V-shaped toothbrush (Oral-B). Plaque index, gingival index and bleeding index were recorded at the beginning of the study (baseline), 2 weeks, 4 weeks and 6 weeks after new toothbrushes were supplied and the results were analyzed statistically. Results: No statistically significant differences were found for plaque index, gingival index and bleeding index between toothbrush groups during the 6 weeks. Plaque and gingival indices were decreased at 2 weeks and 4 weeks but increased at 6 weeks in both toothbrush groups. Bleeding index in the V-shaped toothbrush group showed the lowest value at 2 weeks then increased at 4 weeks and 6 weeks but in the slim bristled toothbrush group decreased from 2 weeks through 6 weeks to under baseline levels. Patients in their twenties had significantly lower values than teenagers in the slim bristled toothbrush group (p < 0.013). Conclusions: The results would suggest that both of the toothbrushes are equally effective but the use of a slim bristled toothbrush may be of benefit in promoting gingival health for fixed orthodontic appliance patients in their twenties and over.

• Imaging Science in Dentistry
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• v.44 no.1
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• pp.61-65
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• 2014

Purpose: This study was performed to evaluate the position of impacted mandibular third molars in different skeletal facial types among a group of Iranian patients. Materials and Methods: A total of 400 mandibular third molars in 200 subjects with different types of facial growth were radiographically investigated for their positions according to their types of facial growth on the basis of the ${\beta}$ angle. The subjects were divided into three groups (class I, II, and III) according to ANB angle, representing the anteroposterior relationship of the maxilla to the mandible. Meanwhile, the subjects were also divided into three groups (long, normal, and short face) according to the angle between the stella-nasion and mandibular plane (SNGoGn angle). ANOVA was used for statistical analysis. Results: The mean ${\beta}$ angle showed no significant difference among class I, II, and III malocclusions (df=2, F=0.669, p=0.513). The same results were also found in short, normal, and long faces (df=1.842, F=2, p=0.160). The mesioangular position was the most frequent one in almost all of the facial growth patterns. Distoangular and horizontal positions of impaction were not found in the subjects with class III and normal faces. In the long facial growth pattern, the frequency of vertical and distoangular positions were not different. Conclusion: In almost all of the skeletal facial types, the mesioangular impaction of the mandibular third molar was the most prevalent position, followed by the horizontal position. In addition, ${\beta}$ angle showed no significant difference in different types of facial growth.

• Journal of Korean society of Dental Hygiene
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• v.13 no.1
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• pp.89-97
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• 2013

Objectives : For investigating relationship between oral condition and body mass of adolescent period and helping to make basic data which make oral care systematically while performing health care for adolescent. Methods : This research was carried out by performing oral and physical test of 273 high school students in some reasons from July 2nd to 16th in 2012. Results : There were significant differences, since the more subjects had irregular occlusion, the more they had loosing tooth(p<0.05). There was a significant difference, since when subjects had more numbers of regular occlusion, they had higher BMI and heavier weight.(p<0.001). There are significant different, since when the subjects had worse peridontal condition, they had more numbers of DT(p<0.001). There was a significant difference in occlusion and body mass group, since when subjects had regular occlusion, 46.4% of subjects were standard body weight, 41.0% of subjects were overweight and when subjects needed orthodontics, 52.7% of subjects were standard body weight, 33.8% of subjects were low-weight, and 13.5% of subjects were overweight(p<0.001). In the correlation between oral condition and BMI, DT index showed negative interrelation with FT index(r=-0.179) and positive interrelation with periodontal condition(r=0.221), MT index showed positive interrelation with occlusion(r=0.137) and FT index showed positive interrelation with height(r=0.136). BMI showed highly positive interrelation with weight(r=0.940), and when occlusion was worse, it shows negative interrelation with BMI(r=-0.293). Height showed highly positive interrelation with weight(r=0.447), and when the more subjects had malocclusion, it showed low negative interrelation with weight (r=-0.257). Conclusions : It was considered that an adolescent period forms health habits, so it was important to increase health action through education for growing healthy adult and not only guiding improvement of dietary life for keeping normal weight, but also conducting oral health education for treating regular occlusion of oral condition and prosthetic procedures for loosing tooth right time.

• Journal of Oral Medicine and Pain
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• v.33 no.4
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• pp.317-322
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• 2008

The moderners of industrial society suffer from various stresses, which bring about increase in prevalence of temporomandibular disorders, oral mucosal disease and chronic neuropathic pain, therefore, the number of patients seeking help of those symptoms tend to increase. The purpose of this study was to discuss the importance of oral medicine related disease by investigating questions that appeared in cyber consultation of Kangnung National University Dental Hospital web site. Among the nearly 2000 questions, the rate of questions related to oral medicine was 20.92%, and the rate of questions related to other departments were oral and maxillofacial surgery 16.87%, conservative dentistry 16.67%, orthodontics 14.02%, prosthodontics 12.25%, periodontics 8.36%, pediatric dentistry 4.93%, preventive dentistry 2.08% and otherwise questions 3.90%. Among the 403 questions related to oral medicine, the frequent questions were oral mucosal diseases 44.17%, temporomandibular disorders 41.19%, halitosis 4.47%, xerostomia 3.23%, other orofacial pain 2.23%, forensic dentistry 1.49% and otherwise questions 2.98%. From the higher rate of questions related to oral medicine compared with other fields of dentistry, we would consider that the people are considerably concerned about the oral medicine related disease, such as oral mucosal diseases and temporomandibular disorders.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.2
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• pp.109-113
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• 2011

Introduction: To correct the facial asymmetry by mandibular jaw surgery, it is important to know the anatomy of the mandible including the mandibular canal positioning of patients with facial asymmetry. This study was performed to evaluate the differences in the cross-sectional surface in the body of the mandible between the deviated side and opposite side in patients with facial asymmetry. Materials and Methods: The study was conducted on 37 adult patients composed of 2 groups, the asymmetry group (n=20) and non-asymmetry group (n=17). Using the cross-sectional computed tomography (CT) images, the distance from the buccal aspect of the mandibular canal to the outer aspect of the buccal cortex, distance from the buccal aspect of the mandibular canal to the inner aspect of the buccal cortex, distance from the inferior aspect of the mandibular canal to the inferior border of the mandible, thickness of the mandible, and cross-sectional surface area of the mandible were measured in each side of the mandible Results: The cross-sectional area of the mandible including the mandibular canal positioning in the deviated side was not statistically different from the opposite side in the asymmetry group. Only the distance from the inferior aspect of the mandibular canal to the inferior border of the mandible in the ramus area of the deviated side was significantly longer than opposite side. On the other hand, the bucco-lingual width of the asymmetry group was thinner than the non-asymmetry group. Conclusion: The cross-sectional area including the mandibular canal of the mandible did not appear to be modified by the facial asymmetry.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.4
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• pp.649-656
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• 2005

The present study was designed to formulate cephalometric norms of normal occlusion for usage in orthodontic diagnosis of malocclusion in Korean children. Thirty two children, aged 4 to 6, with normal occlusion were chosen for this study, Sagittal and vertical relations were analyzed using lateral cephalogram and clinical photos and the measurements were compared with those of adults. On skeletal sagittal analysis, the mean values of the SNA and SNB angles were $83^{\circ}\;and\;78.72^{\circ}$. It showed that the mandible was retrognathic and retropositioned in comparison to those of adults. On skeletal vertical analysis, the mean values of the genial angle was $127^{\circ}$. This showed high angle pattern in children and reduction of genial angle due to counterclockwise rotation of the mandible is expected with growth. On soft tissue analysis, children showed convex pronto, obtuse nasolabial angle. On dental analysis, the mean values of the U1 to SN and IMPA were $91.04^{\circ}\;and\;86.57^{\circ}$. This showed retroclined upper and lower deciduous teeth in comparison to adults. For skeletal values, the liner values were generally greater in males than females.

• The korean journal of orthodontics
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• v.44 no.4
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• pp.195-202
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• 2014

Objective: A low-viscosity resin (infiltrant) was used to inhibit the progression of white spot lesions (WSLs) and resolve associated esthetic issues. An alternative pretreatment was explored to increase the pore volume of the surface layer of the WSLs. Also, the penetration effects of the infiltrant were evaluated for various pretreatments. Methods: Sixty two artificial lesions were fabricated on bovine teeth. As a positive control, 15% HCl gel was applied for 120 seconds. Further, 37% $H_3PO_4$ gel was applied for 30 seconds using three methods. The samples were divided as follows: $H_3PO_4$ only group, $H_3PO_4$ sponge group, and $H_3PO_4$ brush group. The acid was gently rubbed with the applicators (i.e., a sponge or brush) throughout the application time. To compare the effects of resin infiltration, twenty paired halves of specimens were treated with an infiltrant (ICON$^{(R)}$). Results: Thicknesses of the removed surface layers and infiltrated areas were evaluated by confocal laser scanning microscope. The positive control and the 37% $H_3PO_4$ brush group failed to show significant differences in the removed thickness (p > 0.05); however, the mean percentage of the infiltrated area was higher in the 37% $H_3PO_4$ brush group ($84.13{\pm}7.58%$%) than the positive control ($63.51{\pm}7.62%$, p < 0.001). Scanning electron microscope observations indicate higher pore volumes for the 37% $H_3PO_4$ brush group than for the positive control. Conclusions: Application of 37% $H_3PO_4$ with a brush for 30 seconds increased the pore volume of WSL surface layers and the percentage of infiltrated areas in comparison to the use of 15% HCl for 120 seconds.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.29 no.6
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• pp.520-526
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• 2007

The accuracy of model surgery is one of important factors which can influence the outcome of orthognathic surgery. To evaluate the accuracy of digitalized model surgery, we tried the model surgery on a software after transferring the mounted model block into a digital model, and compared the results with that of classical manual model surgery. We could get the following results, which can be used as good baseline analysis for the clinical application. 1. We made the 3D scanning of dental model blocks, and mounted on a software. And we performed the model surgery according to the previously arranged surgical plans, and let the rapid prototyping machine produce the surgical wafer. All through these process, we could confirm that the digital model surgery is feasible without difficulties. 2. The digital model surgery group (Group 2) showed a mean error of $0.0{\sim}0.1mm$ for moving the maxillary model block to the target position. And Group 1, which was done by manual model surgery, presented a mean error of $0.1{\sim}1.2mm$, which is definitely greater than those of Group 2. 3. Remounted maxillary model block with the wafers produced by digital model surgery from Group 2 showed the less mean error (0.2 to 0.4 mm) than that produced by manual model surgery in Group 1 (0.3 to 1.4 mm). From these results, we could confirm that the digital model surgery in Group 2 presented less error than manual model surgery of Group 1. And the model surgery by digital manipulation is expected to have less influence from the individual variation or degree of expertness. So the increased accuracy and enhanced manipulability will serve the digital model surgery as the good candidate for the improvement and replacement of the classical model surgery, if careful preparation works for the clinical adjustment is accompanied.