• Journal of the korean academy of Pediatric Dentistry
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• v.41 no.4
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• pp.314-321
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• 2014

This study investigated the pattern and treatment of traumatic dental injury (TDI), with respect to the time elapsed prior to the initial visit to the Department of Pediatric Dentistry, Chonnam National University Dental Hospital for TDI, from January 2009 to December 2013. The dental trauma records of a total of 378 patients (940 traumatic teeth) were analyzed. The prevalence rate of dental trauma was twofold higher in males versus females. The principal cause of injury, among all participants, was falling (36.5%). The most commonly affected teeth were the maxillary central incisors (66.9%). Subluxation (43.9%) represented the most common trauma for primary teeth, and uncomplicated crown fracture in permanent teeth (30.9%). Only 10% of patients visited the dental clinic within 1 hour of sustaining trauma. The principal treatment provided for primary teeth, during the initial clinical visit, was follow-up (53.2%); for permanent teeth it was root canal treatment (27.3%). The prevalence of root canal treatment for permanent teeth increased commensurate with the time elapsed since injury. These data suggest that delayed checkup following trauma may increase the risk of loss of pulp vitality.

• Restorative Dentistry and Endodontics
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• v.30 no.3
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• pp.170-177
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• 2005

This study was conducted in order to assess whether the form of the shade guide affects in deciding the color of the teeth using the shade guide Eight shade light cured composite resins (Esthet-X, Dentsply, Milford, USA) were used in this study. Shade guides including the model of maxillary central incisors, teeth-form shade guide, doughnut form shade guide, and shade guide with perforated gray shield were prepared with eight shade composite resins and provided the codes randomly After arranging the models of teeth, 19 dentists working at the clinic of the Dentistry of Chonnam University Hospital and 65 students of college of dentistry, Chonnnam University selected the shade guides corresponding to the color of each tooth on the gray board under the D$_{65}$ standard illuminant. Bl shade showed highest accuracy of about 95% among all shade guides of 3 forms applied to the test and regardless of observer, tooth form shade guide showed the highest accuracy (p < 0.05) , and the doughnut form showed the lowest accuracy (p < 0.05). At the time of deciding on the color of the teeth using the shade guides as a result of above, the forms of the shade guides can affect the accuracy, and it suggests that the development of the diversified forms of shade guides, which may obtain more accurate results, is required.

• The korean journal of orthodontics
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• v.48 no.3
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• pp.182-188
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• 2018

Objective: This study was performed to validate the autonomous maximal smile (AMS) as a new reference for evaluating dental and gingival exposure. Methods: Digital video clips of 100 volunteers showing posed smiles and AMS at different verbal directives were recorded for evaluation a total of three times at 1-week intervals. Lip-teeth relationship width (LTRW) and buccal corridor width (BCW) were measured. LTRW represented the vertical distance between the inferior border of the upper vermilion and the edge of the maxillary central incisors. Intraclass correlation coefficients (ICCs) for reproducibility, and the m-value (minimum number of repeated measurements required for an ICC level over 0.75), were calculated. Results: LTRW and BCW of the AMS were 1.41 and 2.04 mm, respectively, greater than those of the posed smile (p < 0.05), indicating significantly larger dental and gingival exposure in the AMS. The reproducibility of the AMS (0.74 to 0.77) was excellent, and higher than that of the posed smile (0.62 to 0.65), which had fair-to-good reproducibility. Moreover, the m-value of the AMS (0.88 to 1.05) was lower than that of the posed smile (1.59 to 1.85). Conclusions: Compared to the posed smile, the AMS shows significantly larger LTRW and BCW, with significantly higher reproducibility. The AMS might serve as an adjunctive reference, in addition to the posed smile, in orthodontic and other dentomaxillofacial treatments.

• Journal of the korean academy of Pediatric Dentistry
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• v.41 no.3
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• pp.199-206
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• 2014

The number of reported traumatic injuries has been increasing in recent years, particularly that of dental trauma in children and adolescents. While the risks associated with dental trauma in this population have been increasingly realized, domestic reports on this issue seem to be insufficient. The purpose of this study was to investigate the prevalence of dental trauma and to evaluate the relevant risk factors and the level of self-recognition. 1,371 adolescents attending middle schools at Yangsan were surveyed via clinical examination and questionnaire; the results were as follows: According to the clinical examination, the overall prevalence of dental trauma was 16.8% with preponderance of males (19.2%) compared to females (13.7%) (p < 0.05). The average number of injured teeth per adolescent with a history of trauma was 1.34. Comparing the prevalence, maxillary central incisors and enamel fracture occupied the highest ranks by tooth type and mode of trauma, respectively. Class II division 1 malocclusion and overjet exceeding 8.0 mm were identified as significant risk factors (p < 0.05). The degree of self-recognition of dental trauma showed a low coincidence rate compared with results of the clinical examination. Males expressed a higher level of satisfaction toward the results of treatment for dental trauma than females (p < 0.05).

• The Journal of Advanced Prosthodontics
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• v.11 no.5
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• pp.239-246
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• 2019

PURPOSE. The purpose of this study was to propose and assess a shade guide for pink gingival aesthetics using a Spanish population sample. MATERIALS AND METHODS. The $L^*$, $C^*$, h, $a^*$ and $b^*$ coordinates of 259 participants were measured using a spectrophotometer in 3 standardized points along the attached gingiva of the maxillary central incisors. A hierarchical clustering analysis was applied to obtain separate solutions regarding the number of shade tabs. For each of the solutions obtained, color differences (${\Delta}E^*$) were calculated using the CIELab and CIEDE2000 formulas, and the proposed shade guide was selected considering (1) the color differences between tabs and (2) the coverage error of each of the solutions. RESULTS. The proposed shade guide consisted of 8 gingival shade tabs and achieved CIELab and CIEDE2000 coverage errors of less than the respective 50:50% acceptability thresholds (${\Delta}E^*=4.6$ units and ${\Delta}E_{00}=4.1$). The coordinates for the various gingival shade tabs were as follows: Tab 1: $L^*43.3$, $a^*21.9$, $b^*12.3$ (1.6); Tab 2: $L^*42.9$, $a^*34.1$, $b^*19.1$; Tab 3: $L^*46.5$, $a^*25.8$, $b^*10.9$; Tab 4: $L^*46.5$, $a^*27.3$, $b^*15.1$; Tab 5: $L^*49.6$, $a^*23.5$, $b^*16.8$; Tab 6: $L^*51.5$, $a^*19.7$, $b^*13.6$; Tab 7: $L^*55.9$, $a^*22.0$, $b^*15.0$; and Tab 8: $L^*56.0$, $a^*19.9$, $b^*18.8$. CONCLUSION. The CIELab and CIEDE2000 coverage errors for the 8 shade tabs of the proposed gingival shade guide were significantly lower than those of other guides. Therefore, despite the limitations of this study, the proposed guide is more appropriate for matching gingival shade in the Spanish general population.

• Journal of the korean academy of Pediatric Dentistry
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• v.46 no.1
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• pp.29-37
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• 2019

The purpose of this study was to investigate the characteristics of intrusion in primary dentition and to evaluate factors influencing complications of primary and permanent dentition during long-term follow-up period. 61 patients (84 teeth) were selected in this study. Medical records of 61 patients were reviewed and age, gender, cause of injury, site of injury, severity of traumatic injury, other injuries associated with trauma, treatment method, and complications of primary and permanent dentition were examined. Collected data were statistically evaluated using Chi-square test and Fisher's exact test. Intrusion in primary anterior teeth was predominant in boys over girls and fall was the most common cause of trauma. It was most common at home and occurred most in the primary maxillary central incisors. Severity had an effect on the incidence of sequelae in permanent successors (p = 0.014). The incidence of complications was significantly lower in patients with soft tissue injuries than in patients with other periodontal injuries (p = 0.000).

• The Journal of Korean Academy of Prosthodontics
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• v.51 no.3
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• pp.199-207
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• 2013

Purpose: The importance of occlusal contacts of the natural dentition for durability of teeth, mandibular stabilization, and restorative dentistry is well known. The purpose of this study is to analyze the occlusal contact and guidance pattern of Koreans by evaluating the static occlusion on maximal intercuspal position and measuring dynamic occlusion during straight protrusion. Materials and methods: The occlusal contacts at maximal interincisal position and the occlusal guidance pattern during straight protrusion of 29 subjects were recorded with shimstock foil (Whaledent, Langenau, Germany), T-Scan III (Tekscan Inc., Boston, MA, USA), polyvinylsiloxane registration material (Genie Bite, Sultan Healthcare, Hackensack, NJ, USA) and compared. Occlusal registration procedures were repeated 3 times. The position was fixed to an upright position and the head position was fixed with the Frankfurt horizontal plane paralleling the horizontal plane. Fisher's Exact Test (R-General Public License, ver. 2.14.1) and Pearson's Test were used to assess the significance level of the differences between the experimental groups (${\alpha}=.05$). Results: When using shimstock foil, T-Scan III system, and polyvinylsiloxane registration material, most of the patients showed contact on anterior, premolar, and molar teeth during maximal intercuspal position. Approximately 51% of maximal intercuspal position showed anterior contact using shimstock foil. When examining the protrusive movement using shimstock foil and T-Scan III system, guidance pattern with the central incisor was the most common. Conclusion: During maximal intercuspal position, there were cases in which not all of the teeth showed occlusal contact. During mandibular protrusive movements, one or more maxillary central incisors frequently joined in straight protrusion and the posterior teeth were disoccluded. Therefore, the anterior teeth protect the posterior teeth, and vice versa. Thus, mutually protected occlusion should be applied when reconstructing occlusion.

• The korean journal of orthodontics
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• v.29 no.1 s.72
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• pp.73-81
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• 1999

Midpalatal suture expansion is often used for patients haying narrow maxillary arch, cleft palate, respiratory handicap with narrow nasal cavity. CGRP has been known as a modulator of pain transmission in central nervous system and a local effector to peripheral tissue causing vasodilation, increase of blood flow, modulation of immune system, regulation of macrophagic function and stimulation of bone formation. To investigate changes of CGRP-immunoreactive nerve fibers in midpalatal suture during the expansion, immunohistochemical study was performed by using rats. Experimental rats (10 weeks, 250 gm) were divided into five groups (control, 1, 4, 7, 14 days group (each n=4) and applied orthodontic force (approximately 200gm) to upper anterior incisors. Frozen sections of midpalatal suture area were immunostained by using rabbit antisera. The results were as follows. ${\cdot}$ The CGRP-immunoreactive nerve fibers were hardly observed in control group. ${\cdot}$ In 1 day group, the CGRP-immunoreactive nerve fibers were more increased around the vessels than control group. ${\cdot}$ In 4 days group, the CGRP-immunoreactive nerve fibers were more increased than control group, but not more increased than 1 day group. Vascular diameter was more enlarged. ${\cdot}$ In 7 days group, especially, hematoxilin affinity of cells was remarkable and cells were arranged along the bone margin. The CGRP-immunoreactive nerve fibers were more reduced than 4 days group and vascular diameter was also reduced. ${\cdot}$ In 14 days group, the CGRP-immunoreactive nerve fibers were similar to those of 7 days group and the irregularity of bone margin was almost recoverd. In Conclusion, the CGRP-immunoreactive nerve fibers nay be related to initial neurogenic inflammatory reaction in expanding mid-palatal suture.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.4
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• pp.642-651
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• 2008

This study was carried out to give basic information of traumatic injuries of primary and permanent teeth which can be used for diagnosis and management of injured teeth. From January 2003 to July 2007, 570 children with 1394 teeth who came to pediatric dentistry and emergency center of Chonnam National University Hospital due to the traumatized teeth participated in this study. The following data were investigated. : age, sex, causes and places of trauma, position of injured teeth, types of injury, and treatment at the first visit. 1. Trauma prevailed at the age of 1, $6{\sim}8$, $17{\sim}18$ and the rate of males was more likely to be higher than the rate of females(1.9 : 1). 2. The main cause of injury is a fall-down injury for primary and mixed dentition, but is a traffic accident and fighting for permanent dentition, respectably. The place of injury for primary dentition is mainly home(45.3%), while street for mixed and permanent dentition. 3. The position of injured teeth according to the area in the mouth is mainly maxillary anterior teeth in both case of primary and permanent teeth and especially, the ratio of central incisors is high. 4. The periodontal tissue injury occurred the most frequently in the primary and the permanent teeth, but the ratio of hard tissue injury in the permanent teeth increased, compared with the primary teeth. 5. Among treatments at the first visit, observation without actual treatment comprised 75.6% in the primary teeth and 55.4% in the permanent teeth, respectably. The pulp necrosis occurred in 20.3% of the primary teeth and 26.6% of the permanent teeth in the case of the periodontal tissue injuries, respectably.

• The Journal of Korean Academy of Prosthodontics
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• v.49 no.1
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• pp.1-7
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• 2011

Purpose: The purpose of this study was to investigate the cutting efficiency of coarse grit diamond burs with air-turbine handpiece on natural tooth. Materials and methods: Four groups of coarse grit diamond bur were selected: Komet (A), Shofu (B), Premier (C), and Mani (D). The extracted maxillary central incisors were used, and ten cuts were made on each specimen, using the rotary diamond burs. The surface of each bur was measured at the upper, middle, and bottom of the bur with confocal laser scanning microscope and imaged with SEM. The data were analyzed with one-way ANOVA and t-test at the significance level of 0.05. Results: The surface roughness was measured. At the A diamond bur, the Sa values were $52.93\;{\mu}m$, $48.32\;{\mu}m$, $46.79\;{\mu}m$, $45.06\;{\mu}m$, and $43.43\;{\mu}m$ for control, test 1, 2, 3, and 4 respectively. The Sa values were $50.68\;{\mu}m$, $45.62\;{\mu}m$, $44.41\;{\mu}m$, $44.10\;{\mu}m$, and $42.46\;{\mu}m$ for B diamond bur, $58.02\;{\mu}m$, $55.53\;{\mu}m$, $52.22\;{\mu}m$, $48.26\;{\mu}m$, and $45.36\;{\mu}m$ for C diamond bur, and $50.11\;{\mu}m$, $46.73\;{\mu}m$, $45.46\;{\mu}m$, $42.58\;{\mu}m$, and $41.80\;{\mu}m$ for D diamond bur. Surface roughness after each bur use showed significant changes, but no significant difference was found in surface roughness change between bur systems. Conclusions: Surface roughness in the same bur system showed significant differences after each tooth preparation. However no statistically significant differences were found in surface roughness between bur systems. The SEM images between control and test 4 showed the abraded particles.