• 대한구순구개열학회지
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• 제15권1호
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• pp.1-10
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• 2012

Parry-Romberg syndrome(PRS) is a degenerative disease characterized by progressive hemifacial atrophy. A 10-year-old girl who had been treated for linear scleroderma at the dermatologic department visited the orthodontic department. The frontal facial photograph showed mild facial asymmetry. On the left side, mild atrophy of soft tissue, enophthalmos, cheek depression, and dry skin with dark pigmentation were observed. The radiograph showed the hypoplasia of both the maxilla and mandible on the left side. This case report describes the treatment of a patient with PRS for 7 years. To minimize the effect of progressive atrophy on the facial growth, a hybrid appliance was used. The facial photos and radiographic records were periodically taken to analyze the progression of PRS. Although it is impossible to prevent the progression of facial asymmetry, it appears to be possible to limit the atrophic effect. After the stabilization of PRS, the orthodontic treatment by the fixed appliance was performed. Additionally, autologous fat graft was performed three times at 6 month intervals. After the treatment, the patient had a confident smile and facial asymmetry was improved.

• 대한치과교정학회지
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• 제20권2호
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• pp.409-417
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• 1990

Tooth movement would be impeded by frictional force arised between archwire and tube, bracket or elastics in the fixed orthodontic appliances, which could be changed variably by such several factors as the contact area, normal (perpendicular) force and the condition of contact surface. There were many literatures about frictional force in the orthodontic region, but different results were obtained from little controlled research so that was very difficult in clinical application. Therefore we have reviewed comprehensively previous literatures about frictional force and thus several results were obtained as follows: 1. For use species of the orthodontic wire, frictional force was influenced mainly by surface roughness of wire in the absence of binding, while that was influenced mainly by normal force in high binding angulation. 2. For the cross-section and diameter of the wire, the contact area influenced mainly on frictional force in the absence of binding, while wire stiffness influenced mainly on frictional force in high binding angulation. 3. The greater the bracket width, the greater frictional force, and frictional force of the plastic bracket was larger than that of the metal bracket. 4. For ligation type, frictional force of the stainless steel ligation was larger than that of the elastic ligation, and frictional force was directly proportional to ligation force. 5. Variable frictional force were occured from the saliva combined with such another factors as normal force and mode of surface oxide et al.

• 대한치과기공학회지
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• 제36권4호
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• pp.277-296
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• 2014

Purpose: This study intends to set standard for organizing the curriculum of short-term dental technicians and the change of job environment, as well as the knowledge & training, by identifying the importance and actual job performance of dental technicians following job analysis in the university education of Dept. of Dental Laboratory Technology, and furthermore to foster junior executives to cope with modernization and globalization. Methods: The tools used in this study are based on the job analysis of research report suggested by National Health Personnel Licensing Examination Board(Lee Gyu-seon, 2011), and it consists of general characteristic 7 items. Every competence duty was measured through Likert 5 point gauging, and internal consistency through Cronbach's Alpha. The competence importance of entire questionnaire was .984 and its performance was .874, reflecting considerably high level, and in terms of each competence duty, high credibility was proved and high internal consistency was verified with competence importance ranging from the minimum .655 to the maximum .966 and its performance ranging from the minimum .677 to the maximum .993. Results: Competence importance and its performance in each duty on the job analysis of dental technicians were measured. In competence importance in each duty, the highest was "checking design order form"(average, 4.52), followed by "selling dental prosthesis"(average 4.49), "making removable orthodontic appliance"(average, 4.48), "open managing dental laboratory"(average, 4.46) in order. However, "making complete denture" was found the lowest(average, 4.23), with importance of all competence dutys was considerably high level. In the performance of its competence duty, "checking design order form"(average, 4.04) was found to be the most importance competence, followed by "making conservative restoration"(average, 4.00), "making porcelain"(average 3.98), "checking working cast"(average, 3.90) in order. However it was found out that "making fixed orthodontic appliance"(average, 3.12) was the lowest, and the importance of all competence dutys was quite high level. Conclusion: The duties of dental technicians consist of 13 kinds, in total, and it was found out that "checking design order form"(average, 4.52) was the most important in the competence importance and job performance. In particular, it was revealed that there was a great difference between the competence importance and its performance in the order of "selling dental prosthesis", "open managing dental laboratory", "making removable orthodontic appliance", "making CAD/CAM prosthesis", and then "making fixed orthodontic appliance".

• 대한치과교정학회지
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• 제33권1호
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• pp.21-29
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• 2003

최근 컴퓨터 소프트웨어의 발전으로 환자의 모형을 scanning하여 3차원 가상 모델을 만드는 것이 가능하게 되었다. 이러한 모델은 컴퓨터로 처리되어 치료 시작부터 끝까지 여러 단계의 치아 이동이 이루어지고, 치아 이동의 각 단계별로 stereolithographic model이 만들어 지는데, 이는 일련의 투명하고 얇은 overlay 장치를 제작하는 기초가 된다. 계획된 치아 이동의 단계에 따라 치아를 움직이기 위해서는 환자가 장치를 항상 사용해야 하며, 중정도의 crowding과 공간 폐쇄는 이 장치로 치료가 용이하다는 것이 입증되었다. 지금까지 이 장치를 경험해 본 결과, 고정성 교정장치에 비해 환자가 불편을 덜 느끼고 심미성과 구강 청결이 좋아 환자의 협조도가 뛰어 났다. 이 장치는 완전히 맹출된 영구치열 환자에서 부정교합에 대한 또 하나의 유용한 접근법이라 할 수 있다.

• 대한치과교정학회지
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• 제23권1호
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• pp.89-100
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• 1993

The purpose of this study was to evaluate the effect of orthodontic force on periodontal cellular activity by immunoperoxidase stain of epidermal growth factor, one of the tissue hormone. And supplementarily, to investigate of the changes of periodontal structures, periodontium was stained by H-E, Masson's Trichrome, P. A. S. stain after orthodontic force application. The experimental animals were four young adult dogs of average 8 month old. The fixed orthodontic appliance was cemented on mandibular right 4th premolar and 1st molar of each animal as experimental site. Mandibular left 4th premolar area of the same animal was used as control. The appliance consist of two silver crown soldered with 0.030' tube, $0.018\times0.022'$ S.S. sectional arch wire, and 0.009' open coil spring for manifestating of orthodontic force for bodily tooth movement of mandibular 4th premolar toward mesial direction. Experimental group was sacrificed at 1, 2, 3, 5 weeks from beginning of the experiment, and was investigated immunohistochemically and bistochemically by several staining methods. Findings were as follows: 1. The degree of EGF staining in control group was highest in epithelium of periodontium, and osteoclasts, osteoblasts and fibroblasts around the capillary were stained at higher level in periodontium. Generally, control group shows positive distribution of EGF all around the periodontal area. 2. The degree of EGF staining in control and 5 week group were similar, and did not show the significant different level between tension and pressure side. 3. All of 1, 2, 3 week group showed the same staining degree and distribution of EGF, and the tension side was more positive reaction of EGF stain than the pressure side. 4. The features of collagen fiber and periodontal fiber arrangement observed by H-E, Masson's Trichrome and P. A. S. stain revealed that oblique periodontal fibers were strectched in tension side, compressed in pressure side of all experimental group. Some fiber group in pressure side of 5 week group recovered the regular arrangement along the capillaries.

• 대한치과의사협회지
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• 제48권11호
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• pp.819-828
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• 2010

Activator is a removable functional appliance used for correcting the skeletal Class II malocclusion in children with the mandibular deficiency. Berlin standard activator modified from Andresen activator has following characters; do not cover the palatal surface for tongue space, relief on lingual surface of mandibular incisors and resin capping 1/3-1/2 of crown height on mandibular incisors for preventing labioversion of mandibular incisors, L-hook between maxillary lateral incisor and canine for anterior high pull headgear, relief on mandibular posterior bite block for differential eruption of posterior teeth. Two cases presented here had a mandibular deficiency and slight maxillary protrusion. First case (an 11-year-old girl) treated with Berlin standard activator and anterior high pull headgear for 13 months followed by fixed orthodontic appliance for another 29 months. Second case (a 12-year-old boy) treated with Berlin standard activator for 6 months followed by fixed appliance for another 24 months. Treatment results showed a significant improvement in sagittal skeletal and occlusal relationship without premolar extraction. Mandibular condyles were concentric in TMJ [ossa, and masticatory muscle activities were normalized after treatment. In the retention period facial harmony and occlusal stability was maintained.

• 대한소아치과학회지
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• 제29권4호
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• pp.568-573
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• 2002

교정치료를 받는 어린이들의 우식활성에 관여하는 요인들을 규명하고자, 고정성 및 가철성 교정장치를 구강에 장착하고 있는 어린이 50명을 대상으로 Cariostat 우식활성검사를 실시하고 우식활성요인으로서 성별, 연령, 교정장치 장착기간, 장치의 종류, 장치를 장착한 부위, Angle씨 부정교합 분류, 우식경험치 수 등의 요인을 조사하였다. 연구대상의 Cariostat 검사성적은 0점과 3점이 각각 1명(2%)씩 있었고 1점이 22명(44%), 2점이 26명(52%)이었다. 저우식활성군의 평균 연령은 9.96세 고우식활성군의 평균 연령은 11.56세로서 두 군간의 차이가 유의하였다(P<0.01). 구강내 교정장치 장착기간은 저우식활성군이 16.13개월, 고우식활성군이 20.48개월로서 고우식활성군의 장착기간이 길었으나 유의한 차이는 없었다(P>0.05). 가철성 장치만 장착한 경우에 비해 고정성 장치를 장착한 경우에서 우식활성이 더 높았다(P<0.01). 상악에만 장착한 경우에 비해 상악과 하악에 다 장착한 경우에서 우식활성이 더 높은 분포를 보였으나 통계학적 유의성은 없었다(P>0.05). Angle씨 I 급 부정교합의 경우에 우식활성이 높고 III 급 부정교합의 경우에 우식활성이 낮은 분포를 보였으나 통계학적 유의성은 없었다(P>0.05). 우식경험치 수는 저우식활성군이 1.83개, 고우식활성군이 1.41개이었으나 유의한 차이는 아니었고(P>0.05) 전체 평균은 1.60개이었다.

• 대한치과교정학회지
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• 제49권2호
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• pp.89-96
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• 2019

Objective: The purpose of this study was to assess the long-term stability of rapid palatal expansion (RPE) followed by full fixed edgewise appliances. Methods: This study included 67 patients treated using Haas-type RPE and non-extraction edgewise appliance therapy at a single orthodontic practice. Serial dental casts were obtained at three different time points: pretreatment ($T_1$), after expansion and fixed appliance therapy ($T_2$), and at long-term recall ($T_3$). The mean duration of the $T_1-T_2$ and $T_2-T_3$ periods was $4.8{\pm}3.5years$ and $11.0{\pm}5.4years$, respectively. The dental casts were digitized, and the computed measurements were compared with untreated reference data. Results: The majority of treatment-related increases in the maxillary and mandibular arch measurements were statistically significant (p < 0.05) and greater than expected for the untreated controls. Although many measurements decreased postretention ($T_2-T_3$), the net gains persisted for all of the measurements evaluated. Conclusions: The use of RPE therapy followed by full fixed edgewise appliances is an effective method for increasing maxillary and mandibular arch width dimensions in growing patients.

• 대한치과교정학회지
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• 제51권5호
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• pp.329-336
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• 2021

Objective: To compare the magnitude of external apical root resorption (EARR) 6 months after starting orthodontic treatment using orthodontic aligners (OAs) and fixed appliances (FAs). Methods: This parallel randomized clinical trial included 40 patients randomized into two groups: OA group (n = 20, 160 incisors) and FA group (n = 20, 160 incisors). For evaluation of the tooth length, periapical radiographs and standardized linear measurements of the maxillary and mandibular incisors were acquired before (T0) and 6 months after treatment initiation (T1). EARR was calculated through the difference in length between the two time points (T1-T0). Statistical comparisons were performed by means of using t-tests, chi-squared test and covariance analysis (a = 5%). Results: Rounding of the root apex was observed in both groups; the resorption involved 2.88% of the root length, so 97.12% of the tooth length remained intact. Intragroup comparisons between the two time points revealed a significant difference, with (T1-T0) ranging from -0.52 to -0.88 mm in the FA group and from -0.52 to -0.85 mm in the OA group. In the intergroup comparisons, only tooth #21 presented a statistically significant difference (OA: -0.52 ± 0.57 mm, FA: -0.86 ± 0.60 mm); however, the overall differences between groups were not clinically relevant, ranging from 0.03 to 0.35 mm. Conclusions: OA and FA treatment resulted in a similar degree of EARR in the maxillary and mandibular incisors at 6 months after treatment initiation. However, the amount of resorption was small and does not impair tooth longevity.

• 대한소아치과학회지
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• 제21권2호
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• pp.611-616
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• 1994

A major cause of missing permanent incisors is congenital abscence and extraction because of trauma and pathologic condition. The request for restoration of missing or spaced anterior teeth is common in dental practice. Problems, such as the tilting, drifting, and rotation of teeth adjacent to the space, complicate the restoration of apperance, and a normally simple restorative dental procedure may become difficult. There are two primary treatment alternatives to improving a dentition's irregular and spaced apperance-closing the space by orthodontic means or providing a prosthesis to disguise the space. The treatment choice depends on many variables, but, as a general rule, patients with a normal overbite, overjet, and buccal relationship are better treated by maintaining the sapce and providing a prosthesis, either fixed or removable. This case report presents two cases : Traumatic loss of maxillary right and left central incisors, Extraction of malformed mandibular right central inciosr. The loss of central incisor space was regained by the fixed-removable and fixed orthodontic appliance, and then Maryland bridge was cemented.