• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.46 no.6
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• pp.422-427
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• 2020

Management of maxillofacial trauma includes primary care, in which diagnosis and management of dentoalveolar injury play a vital role. Due to the impact sustained during a maxillofacial injury (whether direct or indirect), dentoalveolar injuries can occur, leading to fracture and displacement of teeth and associated alveolar bone into the surrounding soft tissues and associated structures, such as the maxillary sinus, nasal cavity, upper respiratory tract, tracheobronchial tree, or gastrointestinal tract. Undiagnosed displaced teeth may cause complications such as airway obstruction. This paper reports a case of displaced teeth in the nasal cavity and gastrointestinal tract and highlights the management protocol for displaced teeth secondary to maxillofacial trauma.

• 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.

• Journal of the korean academy of Pediatric Dentistry
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• v.44 no.2
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• pp.188-193
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• 2017

Natal teeth that are already present at birth and neonatal teeth that erupt shortly after birth may cause various complications. The purpose of this study is to evaluate the characteristics of natal/neonatal teeth in Korean infants who visited to Kyung Hee University Dental Hospital from 2006 to 2015. A retrospective review of clinical data, including the sex of the patients, chief complaints of the mothers, clinical appearances and locations of the natal/neonatal teeth, and associated complications and treatments, was collected. Overall, a total of 75 teeth were found in 48 patients and 69% of the infants had natal teeth, while 31% had neonatal teeth, all of which were mandibular incisors. Females showed more natal/neonatal teeth than males. Major reasons for visiting the dental clinic were parental anxiety, referrals from other clinics, Riga-Fede disease, and pain during breastfeeding. Extraction was the most common treatment choice; observation and grinding were also used.

• Journal of the korean academy of Pediatric Dentistry
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• v.43 no.3
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• pp.254-263
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• 2016

Many studies on the prognosis of avulsed teeth were published but follow-up studies on Korean children and adolescents are insufficient. The aim of this study was to identify clinical factors determining the healing and prognosis of permanent incisors that were replanted after avulsion injury. This study included 184 permanent teeth in 142 patients aged 6-14 years. The clinical and radiographic data of the patients were analyzed from electronic medical records. Immature teeth had a higher probability of pulp revascularization than mature teeth. When extra-alveolar time was longer than 60 minutes, the incidence of inflammatory root resorption (IRR) was higher in immature teeth than mature teeth. However, the incidence of replacement root resorption (RR) was higher in mature teeth than immature teeth under the same condition. The incidence of IRR was increased when pulp was extirpated more than 20 days after replantation. IRR had a more significant influence on the decrease of survival expectation than RR. There was no significant correlation between the root development stage and survival expectation. However, when RR occurred, immature teeth survived shorter than mature teeth. Long term follow-up results from this study are expected to be used as fundamental data for the treatment guidelines and evaluation of the prognosis of replanted teeth.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.35 no.4
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• pp.366-376
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• 1999

In order to examine the catching selectivity of the ark shell(Scapharca broughtonii) dredge, the various factors affecting the selective action of the dredge are analyzed, and the probabilities of the ark shell not shifting through the gaps between the teeth, and the mesh of the netting bag, are calculated for the various shell lengths, using the relation between the posture and the length when the shell passes through these parts.Considering that the probability of making catch is the product of the both probabilities described above, and that this probability is proportional to the relative catching efficiency, the selectivity curves for the ark shell dredge were estimated for various gaps between the teeth and for the various mesh sizes of the netting bag. The obtained results are summarized as follows :1. The ratios of the shell length of ark shell to the distance between teeth indicating the relative catching efficiency of 0%, 50, 100% respectively were 1.0, 1.26~1.28, 1.47~1.44, and that the selection ranges of selective shell length by the distance between teeth were 0.47~0.44, where the distances between teeth were 3.2cm, 3.6cm, 4.0cm, 4.4cm and 4.8cm. 2. The ratios of the shell length of ark shell to the mesh size indicating the relative catching efficiency of 0%, 50%, 100% respectively were 0.67, 0.84, 0.97 and that the selection range of shell length for catching, that in the range of selective shell length by the mesh size was 0.31, where the distance of 4.0cm between teeth, mesh size of 6.0 cm and the smaller mesh angle of $60^{\circ}$3. Where the distance between teeth is 4.0 cm and the smaller mesh angle is $60^{\circ}$, the selection range of shell length for catching of the ark shell dredge is decreased according to the mesh size, and it is minimized by 0.20 in the mesh size of 9.0~10.0 cm, but increased in the mesh size of over 11.0 cm. 4. Where the distance between teeth is 4.0 cm, the selective action by the mesh size of netting bag is begun with the mesh size of over 10.0 cm.

• The Journal of Korean Society for School & Community Health Education
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• v.15 no.2
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• pp.103-113
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• 2014

Objectives: The purpose of this study was to clarify the relationship between perceived oral health and oral health status, oral health symptoms in elementary school students. Methods: Oral examination and oral hygiene survey were performed on 446 students in 5th grade from 4 elementary schools in Wonju, Gangwon province. Oral examination assessed decayed teeth, filled teeth, missing teeth from decay. Then, oral hygiene status was evaluated by O'Leary index and self-reported questionnaires were surveyed. We analysed the collected data using SPSS program ver. 20.0, significant difference level was p<0.05. Results: 38.4% of the subjects rated their oral health as poor, 61.6% as good, female students was worried about their appearances than male students. Their decayed teeth was 1.01, missed teeth was 0.01, filled teeth was 1.75, O'Leary index was 64.49, oral hygiene status of them was poor. Perceived oral health was associated to decayed teeth, DMFT, oral health symptoms except tooth fracture and pain of mucosa (p<0.05). However, there is no correlation between perceived oral health and oral hygiene status (p>0.05) Conclusion: Self-rated oral health status of the elementary school students was related to decayed teeth and oral health symptoms, but it was not related to oral hygiene status. Therefore it was needed to improve the oral hygiene status in elementary students by devise effective way to motivate them.

• Journal of the korean academy of Pediatric Dentistry
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• v.25 no.4
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• pp.749-760
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• 1998

The main purpose of this study was to evaluate the effect of dentin with various pretreatment application time on the dentin surface structure and the bond strength of glass ionomer restorative matrials between primary and permanent tooth. There are difference of composition, structure and pretreated effect of dentin conditioning between the primary and permanent teeth. Inspite of thease fact, we used the same application time of permanent tooth. This study intends to determine the most effective application time using SEM analysis of the surface change by dentin conditioning. Forty five intact primary and permanent teeth were splited mesiodistally with seperating diamond disk. Each eight specimens were prepared for shear bond strength test. (randomely devided eight group as follows:) group I conditioning for five seconds group II conditioning for ten seconds group III conditioning for fifteen seconds group IV conditioning for twenty seconds Additional specimens were prepared to SEM analysis. The result are as follows: 1. Primary teeth are higher shear bond strength in group I and group II. 2. There was no statistically significant difference between primary and permanent teeth in group III and group IV. 3. In SEM analysis, smear layer removal by dentin pretreatment of primary teeth was faster than permanent teeth. Primary teeth may require shorter pretreatment time of dentin for G-I restoration than that of permanent teeth.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.1
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• pp.67-71
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• 2001

A cyst that develops in children's jaw occasionally disturbs the eruption of the succedaneous teeth. These teeth, however, usually have the potential of eruption. So, if the obstacles to eruption are eliminated, it is possible that the teeth erupt spontaneously to their normal position. In those cases, it usually requires the management of the cyst and the eruption guidance of the displaced teeth. Many surgical procedures have been described for the elimination of cysts. When the cyst is large and displaces the permanent teeth, marsupializaion is a surgical technique that may be preferred to enucleation in treatment of cysts. In marsupializaion, if the opening is maintained properly, it may be possible to manage the cyst and guide the displaced teeth into the normal position. In these cases, the cysts were managed with marsupialization in concomittent application of acrylic obturators, and as a result the displaced permanent teeth were guided into normal position. Even though the etiologic factors of the two cases are different, the treatment was the same. And both cases show that the potential for heal ing is remarkable with spontaneous relocation of displaced tooth, provided the opening is maintained during the eruption of the permanent tooth.

• The korean journal of orthodontics
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• v.20 no.2
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• pp.267-280
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• 1990

The purpose of this study was to investigate the force mechanism of Multiloop Edgewise Arch Wire and the intensity and distribution of stresses with vertical and intermaxillary elastics. The obtained results were as follows. 1. When plain wires were inserted and vertical and intermaxillary elastics were used in the upper and lower arch, the stresses of the anterior and posterior ends of wires were observed greatly but the stresses of the premolar were very small. 2. When MEAW were inserted in upper and lower arch, the upper 1st and 2nd premolar and the lower 1st premolar were extruded greatly. 3. In the area of the upper 1st molar and the lower 2nd premolar and the lower 1st molar, any stresses were not observed. 4. The vertical elastic counteracted the intrusion force of the MEAW in the anterior teeth but could not affect on posterior teeth. Using with the Class II elastics, the distal tipping force and extrusion force were exerted in the upper anterior teeth and the intrusion forces of the lower anterior teeth were relieved. Using with the Class III elastics, the extrusion force were exerted in the upper and lower anterior teeth, the distal tipping force were increased in the lower posterior teeth. 5. The Class II elastic counteracted the anterior intrusion force of the MEAW and extruded and tipped mesially the lower 2nd molar. The intrusion force of the MEAW also could not overcome the extrusion force of the class II elastics. 6. When the Class III elastics were engaged, the upper 2nd molar was extruded in spite of the intrusion forces of the MEAW and the extrusion forces of the lower anterior teeth and distal tipping forces in the posterior teeth were observed.

• The korean journal of orthodontics
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• v.45 no.5
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• pp.261-267
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• 2015

Objective: To measure aspartate aminotransferase (AST) activity in the pulp of teeth treated with fixed appliances for 6 months, and compare it with AST activity measured in untreated teeth. Methods: The study sample consisted of 16 healthy subjects (mean age $25.7{\pm}4.3$ years) who required the extraction of maxillary premolars for orthodontic reasons. Of these, 6 individuals had a total of 11 sound teeth extracted without any orthodontic treatment (the control group), and 10 individuals had a total of 20 sound teeth extracted after 6 months of orthodontic alignment (the experimental group). Dental pulp samples were extracted from all control and experimental teeth, and the AST activity exhibited by these samples was determined spectrophotometrically at $20^{\circ}C$. Results: Mean AST values were $25.29{\times}10^{-5}U/mg$ (standard deviation [SD] 9.95) in the control group and $27.54{\times}10^{-5}U/mg$ (SD 31.81) in the experimental group. The difference between these means was not statistically significantly (p = 0.778), and the distribution of the AST values was also similar in both groups. Conclusions: No statistically significant increase in AST activity in the pulp of mechanically loaded teeth was detected after 6 months of orthodontic alignment, as compared to that of teeth extracted from individuals who had not undergone orthodontic treatment. This suggests that time-related regenerative processes occur in the dental pulp.