• Maxillofacial Plastic and Reconstructive Surgery
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• 제35권1호
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• pp.55-59
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• 2013

In the oral and maxillofacial area, bone defects are created by various reasons and demand for bone grafts, while dental implant implantation has been increased consistently. To solve these problems, there has been development of autogenous tooth-bone graft material (AutoBT$^{(R)}$, Korea Tooth Bank Co., Korea), and we have collected ground reasons to substitute free autobone graft with this material in clinical use. This autogenous tooth-bone graft material is produced in powder type and block type. Block type is useful in esthetic reconstruction of the defect site and vertical and horizontal augmentation of alveolar bone because this type has high strength value, well maintained shape and is less absorbed. Therefore, the author of this study gained favorable result by grafting the block type autogenous tooth-bone graft material after dental implant implantation on the bone defects of the mandibular molar extraction site. Moreover, the author represents this case with literature review after confirming bone remodeling on the computed tomography image and by histological analysis.

• 한국기계가공학회지
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• 제16권5호
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• pp.1-6
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• 2017

Gear tooth micro-geometry modifications include the intentional removal of material from the gear teeth flanks, so that the shape is no longer a perfect involute. If the gear shapes are perfect, then the gear tooth meshing is better, therefore the gears will transmit input torque in a more efficient manner without the generation of high frequency engine fluctuation noise. In this paper, we study tooth micro-geometry optimization of rear gear set in 2 speed planetary gear reducers. Analysis revealed problems which are need of modification. Based on the results, tooth micro-geometry was used to deal with load distributions on the rear gear set.

• 대한소아치과학회지
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• 제34권1호
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• pp.53-61
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• 2007

치아우식증이나 치주질환으로 치아를 상실한 경우 여러 가지 방법으로 수복 치료할 수 있으나 그 중에서 임플란트와 치아 이식에 대한 관심이 높아지고 있다. 최근에는 치아 이식에 대한 성공률을 높이기 위해서 치아를 형성시키고 발육시키는 과정에 관한 많은 연구가 이루어지고 있다. 치아싹 이식은 생체 내와 생체 외에서 연구되고 있고, 생체 내 이식은 쥐와 생쥐, 고양이, 개 등 여러 동물에서 시행되고 있다. 이러한 생체 내 이식은 대부분 구강 외에서 시행되고 있으며 구강 내 이식에 대한 연구는 드물다. 본 연구는 악골 내에 이식한 치아싹이 발육되고 석회화되는지 관찰하기 위하여 성숙한 흰쥐의 상악 제 1 구치를 발치하고 그 발치와에 임신 13.5일 된 태아쥐에서 모상기의 하악 제 1 구치의 치아싹을 이식하고 2, 6 개월 후 희생하여 방사선학적 그리고 조직학적으로 관찰하여 다음과 같은 결과를 얻었다. 12 개월과 6개월 동안 악골 내에 이식한 치아싹은 석회화된 치아 조직이 형성 되었고 치아 조직에서 상아질과 백악질, 치수 조직이 관찰되었으며 법랑질 공간 주변은 상피로 둘러싸여 있었다. 2. 6개월 동안 구강 상피 하방에 위치한 치아 조직은 상피로 둘러싸여 있었고 주위에 치주인대 및 결합조직이 관찰되었다. 3. 이식한 시간이 경과함에 따라 치아 형성이 진전되었으나 치아 조직은 크기가 작았고 형태학적으로 완전하지 못하였다.

• Journal of Periodontal and Implant Science
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• 제43권6호
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• pp.276-282
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• 2013

Purpose: The aim of this study was to explore root shape abnormalities, to investigate the influence of root form abnormalities on periodontal attachment loss, and to gather basic data to assist in the diagnosis and treatment of aggressive periodontitis. Methods: From January 2010 to June 2012, a survey was conducted of all 3,284 periodontitis patients who visited the Department of Periodontology, Daejeon Dental Hospital, Wonkwang University School of Dentistry. Clinical parameters (probing depth, periodontal attachment loss, missing teeth) were measured and a radiographic examination was performed at the baseline. We classified the root shape abnormality of bicuspids and molars based on Meng classification. Results: The periodontal attachment loss was the highest at the maxillary first molar (6.03 mm). The loss of the second molar was prominent. Type V deformity was shown to be the most common in the second maxillary and mandibular molars (P<0.05). Type V root shape was associated with the highest attachment loss (P=0.01). Conclusions: Considering the small population and limited design of this study, definitive conclusions cannot be drawn. We suggest larger scale, methodologically more sophisticated studies that include normal controls and chronic periodontitis patients to clarify whether root form abnormalities are a potential risk factor for aggressive periodontitis.

• 대한심미치과학회지
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• 제7권1호
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• pp.64-70
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• 1998

Recently as the interest on Esthetic Dental Prosthesis is arising, the domains of Esthetic Dentistry is being widely investigated. Esthetic Dental Prosthesis is influenced greatly by the shape, color, tooth arrangement of the teeth and the facial features(including the lips). So the degree to which these characters harmonize will be the professional esthetical standard while the satisfaction of the patient will be another esthetical measure. The reason for this is that each and every one of us has a different standard of what is considered beautiful. Of course it doesn't mean that every standard is correct. Then what does Esthetical Prosthesis mean and what should the standard be? This must be defined as a prosthesis that satisfies the basic requirements - margin, contour, occlusion, and at the same time it should restore the shape, color, and tooth arrangement which the client(patient) would love to have. As Esthetic Prosthesis contains its subjective meaning a great deal, it shouldn't be simply distinguished between the beauty of the teeth itself or ugliness. Also in some case, it needs surgical treatment to make it harmonious in the whole aspect so that one may keep the feeling of satisfaction and security. Then what is the shape, color, tooth arrangement that each individual wants? There is an indefinite variety. For example, considering arrangement both regular and irregular is considered beautiful by each different individual. Regular arrangement may be the standard of beauty for some, while irregular arrangement may be thought of as natural looking and beautiful. That is why there must be enough communication with the patient and an agreement be made at the clinic before a diagnostic plan and actual surgery. The treatment plan as mentioned above must be sent to the dental laboratory. In this research, by using case studies, I am going to the importance and appropriateness of the data and information for the dental technician's esthetic prosthesis.

• 대한소아치과학회지
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• 제37권4호
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• pp.488-496
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• 2010

치외치는 교합면에 법랑질이 원추형으로 돌출되어 결절을 형성한 치아로서, 치아발육 중 법랑기의 내측법랑상피가 외부로 과증식되거나 치수 간엽조직이 국소적으로 과증식되어 나타난다. 교합력이나 저작에 의해 파절 또는 마모되기 쉬우며 따라서 이로 인하여 치수노출에 의한 감염이 야기될 수 있다. 상악 전치부 설면에도 원추형으로 돌출된 결절이 관찰되기도 하는데 이를 탈론 교두(talon cusp)라 한다. 치내치는 치아 발육 중 설측의 법랑상피가 일부 함입되어 설측에 깊은 소와가 형성된 형태로서 크기나 전체적인 모양은 정상이다. 방사선 사진상에서 치경부의 법랑질 일부가 함입되어 함입강을 형성하고 그 기저부는 치수에 가까이 위치하고 있어 치수와 개통되어 있을 가능성도 있다. 탈론 교두(talon cusp)와 치내치는 비교적 흔한 형태 이상이지만, 한 치아에 동시에 발생하는 경우는 매우 드물다. 이러한 환자에서 탈론 교두(talon cusp)가 교합력이나 저작에 의해 파절되거나, 교두 사이 열구가 우식에 이환되어 치수치료가 시행 될 때, 치내치의 복잡한 근관 형태로 인해 많은 어려움이 있다. 따라서 교합조정, 치면열구전색술 등의 예방적 처치와 주기적인 검진이 필요하고, 치수치료시 정확한 방사선학적 진단을 통한 치내치의 근관 형태 파악이 필요하다. 조선대학교 치과병원 소아치과에 내원한 10세 남아(하악 좌측 중절치)와 8세 여아(상악 우측 중절치) 그리고 7세 남아(상악 우측 중절치)에서 치내치를 동반한 탈론 교두(talon cusp)가 관찰되어 본 증례를 보고하고자 한다. 9세 남아와 8세 여아는 치수 병변으로 인해 치수 치료 중이고, 7세 남아는 병적 소견 없이 교합조정 후 관찰 중이다.

• 한국공작기계학회논문집
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• 제13권5호
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• pp.62-66
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• 2004

A study for investigating the effects of the cutting conditions(feed rate, radial depth of cut, cutting speed) and the tool diameter on the circumferential geometry of the cyl indrically end-mi1led workpiece is described. In this work, the circumferential geometry is characterized by the roundness error. Experimental results show that the circumferential geometry is directly affected by the material removal per tooth,which is defined as a function of the cutting speed, the feed rate and the radial depth of cut. And, the radial depth of cut is revealed to be the most critical condition among them. It is also found that the roundness error decreases when the tool diameter is larger under the same cutting conditions.

• 대한심미치과학회지
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• 제14권1호
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• pp.15-18
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• 2005

In order to recover the esthetic of the missing anterior area, we must consider color, shape of a tooth and the functions of a prosthesis that is harmonized with the surrounding factors. When the tooth of a natural tooth is exposed, we face to challenge to restore them. several factors cause resorption of bones, in flammation, and gum trouble, and a defective prosthesis damages the aesthetics of the gingiva. There are two ways how to solve these problems. One can be done by periodontal surgery and the other can be done by prosthesis. Most patients want aesthetic restoration that is harmonized with their teeth and gingiva. So if prosthesis is fabricated to expose the root exposed, it is far from the patient's expectation.

• 한국자기공명학회논문지
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• 제8권1호
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• pp.37-46
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• 2004

When human tooth enamel is exposed to the X-ray or ${\gamma}$-rays, free radicals and defects are created in a small quantity of carbonate enclosed in the tooth enamel. The intensity of the ESR signal of the free radicals is almost proportional to the absorbed radiation dose. However this dosimetric character is affected to some extent with the measurement temperature and thermal treatment of the samples. We found that the shape of the ESR signals of the samples is dependent upon the measurement temperature, the thermal annealing prior to the irradiation and that after the irradiation.

• 대한치과보철학회지
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• 제36권1호
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• pp.150-165
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• 1998

For the purpose of evaluating the effect of both direct retainer design and bony absorption degree around abutment of indirect retainer on the supporting tissue of abutment of indirect retainer, dislodging force was transmitted to unilateral distal extension RPD bases. Analysis of stress distributed within the supporting tissue around abutment of indirect retainer was carried out. Using three-dimensional photoelastic stress analysis method and the conclusion is a follows. 1. According to the extent of force which the direct retainer of the most distal abutment tooth, the amount of force transmitted to the abutment tooth of indirect retainer was small. 2. Of all the cases, Mandibular first premolar which was used abutment tooth of indirect retainer, buccal, mesial and distal sides represented compression stress and lingual side represented tensile stress. 3. The more bone resorption of abutment tooth of indirect retainer, the more distortion of buccal and distal side of abutment tooth was existed and the extent of compression stress which was existed and distal side to abutment tooth was large. 4. When the alveolar bone around the abutment with indircet retainer is normal. The amount of force transmitted on abutment with indirect retainer was small in the order of Akers clasp, RPA clasp, RPI clasp. 5. When the alveolar bone around the abutment with indirect retainer has been absorbed 20% and 30%, the amount of force transmitted on abutment with indirect retainer was small in the order of RPA calsp, RPI clasp, Akers clasp. 6. When denture is displaced, shape of the direct retainer reciprocating abutment affect much the function of indirect retainer.