• 제목/요약/키워드: Number of teeth

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PREVALENCE OF GINGIVAL RECESSION AND CERVICAL ABRASION (치은퇴축과 치경부마모의 연령군에 따른 유병률)

  • Han, Soo-Boo;Cheong, Hee-Sun;Moon, Hyock-Soo;Hwang, Kwang-Se
    • Journal of Periodontal and Implant Science
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    • v.25 no.3
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    • pp.459-469
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    • 1995
  • The objectives of this study were to examine the prevalence of gingival recession (GR)and cervical abrasion(CA) and to relate some considered factors to them. We selected 308 subjects, consisting of male 174 and female 134, who had 14 teeth at least. As age increased, the prevalence rates of GR & CA was increased. And both the rates of GR & CA were higher in male than in female. Interestingly, the effect of alcohol consumption was the highest in GR and smoking affected CA highly among several variables. However, we could not prove the direct relationship between drinking & smoking and GR & CA. Only we assumed poor oral hygiene due to drinking & smoking as one of predisposing factors. The result of this study did not show the obvious factor which affected GR and CA greatly. The present study suggested that GR & CA should be related to a number of factors.

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Case report of esthetic maxillary anterior crown lengthening (상악 전치부에서 심미적 치관 연장술의 치유 양상 보고)

  • Kim, Sun-Ha;Park, Jin-Woo;Suh, Jo-Young;Lee, Jae-Mok
    • Journal of Periodontal and Implant Science
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    • v.39 no.2
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    • pp.199-204
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    • 2009
  • Purpose: Excessive gingival display and short clinical crowns due to altered passive eruptions are major concerns for a considerable number of patients visiting dental clinics. Altered passive eruptions could be corrected through various types of periodontal surgery conformable to a classification. 3 cases are reported here on the esthetic correction of altered passive eruption to evaluate results of crown lengthening procedure. Methods: Three patients whose major complaints were excessive gingival display and short teeth were picked out for this case study. Before treatment, clinical and radiological exam was performed to choose type of surgery. Thickness and width of keratinized gingiva was measured in all three patients then they were treated by surgical methods including flap operation and depigmentation under subsequent diagnosis. Results: Uneventful healing and stable gingival margin were observed in all three patients except recurrence of gingival pigmentation of one patient. Conclusions: The treatment of altered passive eruption requires precise diagnostic procedure and could achieve better esthetic outcomes when it is accompanied by other orthodontic and orthognathic treatment.

Root and Canal Morphology of Maxillary Primary Molar using CBCT and 3D CT (CBCT 및 3D CT를 활용한 상악 유구치 치근과 근관 형태)

  • Kim, Joon Hee;Kim, Hyuntae;Shin, Teo Jeon;Hyun, Hong-Keun;Kim, Young-Jae;Kim, Jung-Wook;Jang, Ki-Taeg;Song, Ji-Soo
    • Journal of the korean academy of Pediatric Dentistry
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    • v.48 no.4
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    • pp.437-448
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    • 2021
  • The purpose of this study is to analyze morphological characteristics of maxillary primary molar's root and root canal. 268 children aged 3 - 7 years (175 boys, 93 girls) who had CBCT (152 children) and 3D CT (116 children) taken in Seoul National University Dental Hospital from January 2006 to April 2020 were included. The number of roots and root canals were analyzed in 1002 teeth without any root resorption or periapical pathologies. Curvature, angulation, length of root and root canal, as well as cross-sectional shapes of the root canal were analyzed in 218 teeth. By using Mimics and 3-Matics software, volume, surface area, and volume ratio of root canal was analyzed in 48 teeth. More than half of maxillary primary molars have 3 roots and 3 root canals. The degree of symmetry of root canal type was about 0.63 (Cohen's kappa coefficient). The most frequent shape of roots and canals was linear in 1st primary molars and curved in 2nd primary molars. Angulation, length of root and root canals was the largest on palatal roots. Most teeth showed ovoid or round shapes at apex. The largest root canal volume, surface area, volume ratio was found in the palatal roots.

LONG TERM FOLLOW-UP OF MULTIPLE ODONTOGENIC KERATOCYSTS ASSOCIATED WITH BASAL CELL NEVUS SYNDROME: A CASE REPORT (기저세포모반 증후군과 관련된 다발성 낭종의 장기 치료결과: 증례보고)

  • Lee, Eun-Young;Kim, Kyoung-Won
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.32 no.1
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    • pp.81-85
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    • 2010
  • Multiple jaw cysts are one of the most constant features of the basal cell nevus syndrome. Basal cell nevus syndrome is inherited as an autosomal dominant trait with variable expressiveness. This syndrome comprises a number of abnormalities such as multiple nevoid basal cell carcinomas of the skin, skeletal abnormalities as bifid rib and fusion of vertebrae, central nervous system abnormalities as mental retardation, eye abnormalities with multiple jaw cysts. The odontogenic keratocysts in patients with this syndrome are often associated with the crowns of unerupted teeth and huge size; on radiographs they may mimic dentigerous cysts. The most important feature of the cyst is its extraordinary recurrence rate. Since recurrence may be long delayed in this lesion, follow-up of any case of odontogenic keratocyst with roentgenograms and clinical examination of basal cell carcinoma are essential for at least five years after surgery. We report the result of 7-year follow up after cyst enucleation associated with basal cell nevus syndrome with the literature of review.

A Study on 3D Modeling & Stress Analysis of Helical Conical Involute Gear (헬리컬 코니칼 인볼류트기어의 3D 모델링과 치면 응력해석에 관한 연구)

  • Kang, Jai-Hwa;Lee, Do-Young;Kim, Jun-Sung;Xu, Zhe-Zhu;Lyu, Sung-Ki
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.13 no.1
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    • pp.45-51
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    • 2014
  • Generally, marine transmissions contain straight shafts and helical gears, meaning that enginerooms require more space. In order to guarantee a levelengine space for conical involute gears or beveloid gears, both of which are important machine parts, a conical gear was used to replace the traditional cylinder gear. Owing to weak points such as the point contact phenomenon of the teeth, a limitation of the width of each tooth in terms of the addendum, the variational modification coefficient,and the difficulty of processing, research about conical involute gears remains at a standstill. Along with the increasing number of applications of conical involute gears, research on conical gear design technology is necessary. In this paper, in an effort to enhance conical gear design technology, research on the 3D modeling and stress analyses of helical conical involute gears were done.

A SURVEY ON THE ORAL HEALTH STATUS OF THE DISABLED IN BUSAN, KOREA (부산광역시 장애인 구강건강 실태)

  • Yun, Hyun-Seo;Jo, Byung-Jun;Bae, Kwang-Hak;Jeong, Tae-Sung;Kim, Jin-Bom
    • The Journal of Korea Assosiation for Disability and Oral Health
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    • v.1 no.1
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    • pp.25-32
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    • 2005
  • The purpose of this study was to furnish data on the disabled's oral health status of the disabled in Busan, Korea. Material and Methods: Two dentists who were well experienced in caries examination surveyed the oral health status on 793 of disabled men in Busan from March to June in 2000 under natural solar light with plane mirror by the criteria which are suggested by World Health Organization (WHO). Results: The number of present permanent teeth of the disabled are lower than the undisabled. DMF rate and DMFT indices of the disabled were higher than the undisabled. DT rate of the disabled was higher than the undisabled. Conclusions: The development of community oral health care programs for the prevention and treatments of dental caries for the disabled is needed and active administrative policies should be established for the promotion of the disabled's oral health.

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Health-related quality of life according to oral health behavior in adults (성인의 연령별 구강건강행위에 따른 건강관련 삶의 질에 관한 연구)

  • Hwang, Su-Hyun
    • Journal of Korean Dental Hygiene Science
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    • v.2 no.2
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    • pp.21-30
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    • 2019
  • This study identifies oral health behavior factors related to the health-related quality of life(EQ-5D) of adults. Three groups are analyzed, young adults(aged 19 to 39 years old), middle-aged(40 to 64 years old), and elderly(over 65 years old). By comparing the factors related to health-related quality of life by age, we will provide information for improving the overall quality of life, including oral health for current and future elderly. Using raw data from the 1st year(2016) of the National Health and Nutrition Survey, the oral health behaviors of the study subjects were compared. These included: the number of times teeth were brushed, the time brushing took place, the use of interdental care products, and whether they went for oral and examinations. There was a statistical significance in treatment experience and drinking habits. There was also a significant influence on the health-related quality of life across the age groups. Therefore, it is possible to improve the health-related quality of life, including oral health practices according to age. It will be necessary to develop and apply.

A study on the clamping type forging of helical gear (헬리컬기어의 구속형 단조에 관한 연구)

  • Choi, J.C.;Choi, Y.;Tak, S.J.;Cho, H.Y.
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.21 no.11
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    • pp.1827-1836
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    • 1997
  • In this paper, the clamping type forging of helical gears has been investigated. Clamping type forging is an operation in which the product is constrained to extrude sideways through an orifice in the container wall. Punch is cylindrical shaped. The punch compresses a cylindrical bilet placed in a die insetr. As a consequence the material flows in a direction perpendicular to that of punch movement. The forging has been analysed by using the upper-bound method. A kinematically admissible velocity field has been developed, wherein, an involute curve has been introduce to re4present tooth profile of the gear. Numerical calculations have been carried out to investigate the effects of various parameters, such as module, number of teeth, helix angle, friction factor and initial height of billet on the forging of helical gears. Some firgiing experiments were catrried out with aluminium alloy to show the validity of the analysis. Good agreement was found between the predicted values of the forging load and obtained from the experimental results.

Oral health and hygiene in the neurosurgical patients in intensive care unit (일부 대학병원 신경외과 중환자실 환자의 구강상태에 관한 연구)

  • Kim, Eun-Kyong;Lee, Hee-Kyung
    • Journal of Korean society of Dental Hygiene
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    • v.15 no.1
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    • pp.147-152
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    • 2015
  • Objectives: The purpose of this study was to investigate the oral health and hygiene in the neurosurgical patients in intensive care unit(ICU). Methods: The subjects were 92 neurosurgical patients in intensive care unit(ICU) from March, 2011 to December, 2012. The oral examination consisted of number of residual teeth, DMFT index, clinical attachment loss, gingival index, plague index, and Candida species colony of tongue and saliva. Plaque was inoculated from tongue and saliva and incubated in 36.5C incubator for 48 hours using $Dentocult^{(R)}$ CA(Orion Diagnostica, Espoo, Finland). Glasgow coma scale(GCS) was measured to evaluate the consciousness of the patients on the basis of medical record. Results: Oral health was poor in clinical attachment loss and gingival index. Oral hygiene in neurosurgical patients in ICU was very poor due to high plaque index and Candida colonization of tongue and saliva. Plague index was closely related to Candida colonization of tongue and saliva(p<0.05). Conclusions: Oral health and hygiene of patients in neurosurgical ICU were very poor. More careful oral hygiene care is very important and necessary to enhance the oral health improvement of the neurosurgical patients in ICU.

A Study on the Adequate Radius of Circular Arc in the Involute-Circular Arc Composite Tooth Profile (인벌류우트-원호 합성치형의 적정 원호반경에 대한 연구)

  • 정인승;손지원;윤갑영
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.11 no.2
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    • pp.296-303
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    • 1987
  • The composite gear which is composed of involute curve and circular arc has been studied. In the vicinity of pitch point, its profile is an involute curve, and in the dedenum, a circular arc. The curve in the dedendum is generated by the circular arc of the mating gear. Though the available range between minimum and maximum radius of circular arc can be given by existing tooth profile equation, there was no formulation which relates design parameters to the desired radius. It is attempted to get the formula for the radius of circular arc as a function of design parameters, such as unwounded angle, number of teeth, module, and pressure angle. The radius of circular arc, the chordal tooth thickness at working root circle, nominal bending stress, Hertz stress and contact ratio obtained from derived formula are compared with those of the existing design criteria. And these are compared with those of involute gear.