• The Journal of Korean Academy of Prosthodontics
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• 제49권1호
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• pp.38-48
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• 2011

Purpose: Dentists suffer back, neck and shoulder pain during their careers due to bad operating posture. If dentists have a good operating posture ergonomically, there would be less pain and discomfort in the shoulder and back. Therefore, dentists should learn the Home position which enables dentists to approach a stable posture ergonomically. This study was to compare tooth preparation in the Home position and the Random position, and evaluate the clinical efficacy of the Home position. Materials and methods: Tooth preparation for fixed partial denture was performed on the maxillary left 2nd premolar and maxillary left 2nd molar at the two different operating positions were compared. The amount of occlusal reduction, marginal width, subgingival margin depth, and convergence angle were measured. A T-test was performed separately to compare the results of the Random position and the Home position. Results: 1. The amounts of average thickness of occlusal reduction on fossa were deficient to the ordered ones in the Random position and the Home position (P > .05). 2. The average subgingival margin depth of prepared margin on maxillary left 2nd premolar, maxillary left 2nd molar were excessive in the Random position than in the Home position. On the maxillary left 2nd premolar, there was no statistical difference in the Random position and the Home position except Distal midline, DL line angle, Lingual midline, ML line angle (P< .05). On the maxillary left 2nd molar, there was no statistical difference in the Random position and the Home position (P < .05). 3. Average convergence angle in the Random position and the Home position were excessive compared to the ordered angle. There was no statistical difference in the Random position and the Home position (P > .05). 4. Analysis of pearson correlation : In the Random position, the amounts of average thickness of occlusal reduction, the average subgingival margin depth of prepared margin, convergence angle were significantly associated with each other (P < .05). But in the Home position, they were not significantly associated with each other (P < .05). 5. The time needed for preparation in the Home position was faster or equal than that of the Random position as time went on. Conclusion: In conclusion, there were no significant differences between Home position and Random position in measures of occlusal reduction, marginal width, marginal depth, convergence angle. However, preparation time and incidence of damaging adjacent teeth were less in Home position than in Random position. Therefore, if trained properly, Home position which is more ergonomically stable can be adopted for clinical use.

• Journal of Dental Rehabilitation and Applied Science
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• 제35권2호
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• pp.105-112
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• 2019

Crown fractures are the most frequent traumatic injuries to permanent teeth and mainly involve the maxillary incisors due to their exposed position in the dental arch. One option for managing crown fractures, when the tooth fragment is present and in good condition, is reattachment of the fragment to its original position. This paper reports on three crown fracture cases in which successful esthetic and functional results were achieved by reattachment of the tooth fragment.

• The Journal of the Korean dental association
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• 제42권2호통권417호
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• pp.150-157
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• 2004

Inverted maxillary incisor is that maxillary incisor rotates counterclockwise direction. The cause of this 'Inverted incisor' is the injury of the deciduous predecessor transmitted to the developing permanent tooth germ or displacement of permanent tooth crown portion from unknown origin. Dilaceration, defined as a distorted root from, may result from mechanical injury during eruption period or ectopic development of tooth germ. This article presents a case of an inverted and dilacerated maxillary right central incisor. Through orthodontic traction, the dilacerated and inverted incisor was successfully moved into the proper position.

• Journal of Oral Medicine and Pain
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• 제14권1호
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• pp.35-42
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• 1989

악구강계의 질환을 진단하고 치료후의 예후를 판정하기 위하여 maximal clenching시에 측정된 tooth contacts의 수와 분포가 이용되어 왔다. 그러나 maximal clenching시 반복된 tooth contacts의 측정은 저작근 피로등 문제점을 가지고 있다. 본연구는 건강한 성인 15명을 대상으로 maximal clenching 및 habitual clenching시 T-Scan system을 이용하여 치아접촉 수와 접촉시간을 측정, 비교 검토하여 habitual clenching을 이용한 방법이 Tooth contacts의 연구에 이용될 수 있는지를 확인 하는데 목적이 있으며, 연구결과는 다음과 같다. 1. Habitual clenching시 upright, semisupine position에서의 전측두근의 근활성은 maximal clenching시의 64.5%, 61.9% 및 73.3%로 나타났다. 2. Maximal clenching시 치아접촉 수와 접촉시간은 16.82개 및 0.429초로 나타났으며 habitual clenching시에는 11.65개 및 0.177초로 나타났다. 3. 치아접촉수와 접촉시간은 체위에 따라 크게 변화되지 않았다. 4. 치아접촉수와 접촉시간의 측정시에 habitual clenching을 이용하는 방법이 maximal clenching을 이용하는 방법보다 재현성이 더 높은 것으로 나타났다. 5. Tooth contacts의 연구시 habitual clenching을 기준으로 사용할 수 있다.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• 제7권1호
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• pp.27-30
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• 1977

To insure accuracy in dental roentgenographs, it is important that the patient's head position and angulation of the x-ray tube. In 1907 Cieszynski applied the rule of isometry to dental radiography and established that in the production of an accurate image of a tooth, the central ray must be porjected perpendicularly to a plane bisecting angle formed by the longitudinal axis of the tooth and the film plane. Proper exposure of the film is a part of the production of a good dental radiograph, and correct processing also makes an essential contribution to the quality of the radiograph. The author analysed the failure of exposure and processing results, and recommended followings. 1. The patient head must be positioned that occlusal plane are parallel with the horizontal floor. 2. Central ray must be projected to the objective tooth and supporting structure and projected as perpendicularly to tooth axis and film surface as possible. 3. In processing, the temperature of the solution and the processing time must be correct.

• Restorative Dentistry and Endodontics
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• 제41권3호
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• pp.210-217
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• 2016

Exposing sound structure of a subgingivally fractured tooth using orthodontic extrusion is considered to be a conservative way to re-establish biologic width without sacrificing esthetics or jeopardizing periodontal support of neighboring teeth. When a misaligned tooth is traumatically involved, a more comprehensive approach combining tooth extrusion and re-alignment may be necessary for a successful restorative outcome. This case report describes a successful esthetic management of a patient with complicated crown-root fracture on the maxillary right central incisor and pre-existing malocclusion in the maxillary anterior region. Forced eruption along with re-alignment of teeth by orthodontic movement seems to allow re-positioning of the fracture line to a favorable position and correction of crowding, providing a better esthetic result.

• The Journal of the Korean dental association
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• 제54권8호
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• pp.592-603
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• 2016

Pathologic tooth migration (PTM) caused by periodontal disease is a relatively common disease with a prevalance rate of 30~55%. It is one of the reasons for periodontal treatment of patients. PTM occurs when various factors related to the position of the tooth are altered and clinical features of PTM include facial flaring, diastema, proximal tilting, rotation, and extrusion of teeth. The purpose of this study was to assess the treatment of teeth of hopeless prognosis through the practice of modified intentional replantation on pathologic migrated tooth. This study presents cases using modified intentional replantation for the treatment of pathologic tooth migration caused by severe periodontitis. Modified intentional replantation is a technique that prepares extraction socket by using an implant drill. Based on 3 cases performed with modified intentional replantation, an improvement of clinical periodontal indicators such as probing pocket depth, bleeding on probing, tooth mobility, and pathologic teeth migration was observed after surgery. Also, the patients were satisfied with the functional and esthetic improvement.

• Imaging Science in Dentistry
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• 제33권4호
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• pp.217-221
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• 2003

Purpose : To evaluate the use of the vertical tube shift from a panoramic film and a periapical film to localize unerupted maxillary incisors and supernumeraries. Materials and Methods : The total of 103 displaced maxillary incisors or embedded supernumeraries were examined in this study. The vertical tube shift technique with panoramic and periapical radiography by normal projection taken and compared to localize the position of the embedded maxillary incisors or supernumeraries by a radiologist and 5 general dentists. The gold standard used for the radiographic comparisons was the true position of the embedded tooth as confirmed by horizontal tube shift technique using three periapical radiographs. The general dentist examiners were instructed on the use of the modified acronym 'SLDOBU' by the radiologist as it pertains to panoramic radiographs as the principle of vertical tube shift. Results: All of the embedded maxillary incisors and supernumeraries were successfully located using the vertical tube shift from a panoramic and a maxillary anterior periapical radiograph by the radiologist and 5 general dentists. Conclusion: The use of a panoramic film with a periapical film combination for a vertical tube shift can be useful to localize unerupted maxillary incisors and supernumeraries.

• Journal of Periodontal and Implant Science
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• 제47권1호
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• pp.41-50
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• 2017

Purpose: The aims of the present study were to compare the image quality and visibility of tooth cracks between conventional methods and swept-source optical coherence tomography (SS-OCT) and to develop an automatic detection technique for tooth cracks by SS-OCT imaging. Methods: We evaluated SS-OCT with a near-infrared wavelength centered at 1,310 nm over a spectral bandwidth of 100 nm at a rate of 50 kHz as a new diagnostic tool for the detection of tooth cracks. The reliability of the SS-OCT images was verified by comparing the crack lines with those detected using conventional methods. After performing preprocessing of the obtained SS-OCT images to emphasize cracks, an algorithm was developed and verified to detect tooth cracks automatically. Results: The detection capability of SS-OCT was superior or comparable to that of trans-illumination, which did not discriminate among the cracks according to depth. Other conventional methods for the detection of tooth cracks did not sense initial cracks with a width of less than $100{\mu}m$. However, SS-OCT detected cracks of all sizes, ranging from craze lines to split teeth, and the crack lines were automatically detected in images using the Hough transform. Conclusions: We were able to distinguish structural cracks, craze lines, and split lines in tooth cracks using SS-OCT images, and to automatically detect the position of various cracks in the OCT images. Therefore, the detection capability of SS-OCT images provides a useful diagnostic tool for cracked tooth syndrome.

• The Journal of the Korean dental association
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• 제22권12호통권187호
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• pp.1067-1073
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• 1984

In the treatment of functional orthodontic problems, timing is not an issue. All orthodontists start as soon as the condition is recognized. However, there is an active dialogue concerning treatment timing for structure problems. The major points in contention center around the operator's ability is to control the growth of the facial bones and to maintain post-treatment tooth position through the maturation period (especially when this position was gained by techniques involving arch expansion or distal driving of posterior segments). Factors taken into account to determine the best time of orthodontic treatment include diagnosis, interception, growth rate, patient cooperation, eruptive state and treatment period. With those exceptions of all functional problems, mild dental discrepancies and skeletal deficiencies with a predictably excellent growth potential (early treatment), the period immediately following the eruption of the permanent second molars is the period during which most orthodontic treatment should be initiated. At this time the full volume of tooth substances is present, the individual growth pattern in well established, there are sufficient teeth to receive nearly any type of appliances and the patient can easily tolerate the wearing of appliances.