• 제목/요약/키워드: Tooth width

검색결과 298건 처리시간 0.022초

전치부 접촉과 측두하악 관절강폭과의 관계에 관한 연구 (A Study on the Relationship between Anterior Tooth Contact and Temporomandibular Joint Space)

  • Sang-Don Kim;Kyung-Soo Han;Min Shin
    • Journal of Oral Medicine and Pain
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    • 제18권2호
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    • pp.43-53
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    • 1993
  • The aim of this study was to investigate the relationship between the presence or absence of anterior tooth contact and the changes in temporomandibular joint space. The study sample consisted of 32symptom-free dental students and 79 craniomandibular disorders patients with unilateral joint dysfunction. The two groups were categorized into control group or experimental group, respectively. Recordings of the number and distribution of occlusal contacts were made by T-Scan system. Transcranial radiographs were taken with using of accurad-100 head positioner. Measured items in transcranial radiographs were anterior, superior, posterior joint space and relative condylar position to deepest position of glenoid folla. According to the presence or absence of anterior tooth contact, each group was subdivided and compared with each other with respect to TM joint space. Data were processed and tested with SPSS/PC + package. The results of the study showed that the joint space in control group were wider than those of experimental group and the difference of the width of joint space was more remarkable in subjects with anterior contact between control group and experimental group. However, in same group whether the presence of anterior tooth contact could hardly affect the difference of the width of joint space. And anterior tooth contact in grouip are more frequent than in experimental group.

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Micro-computed tomography evaluation of general trends in aligner thickness and gap width after thermoforming procedures involving six commercial clear aligners: An in vitro study

  • Palone, Mario;Longo, Mattia;Arveda, Niki;Nacucchi, Michele;De Pascalis, Fabio;Spedicato, Giorgio Alfredo;Siciliani, Giuseppe;Lombardo, Luca
    • 대한치과교정학회지
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    • 제51권2호
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    • pp.135-141
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    • 2021
  • Objective: To assess the effects of thermoforming on aligner thickness and gap width in six aligner systems with the same nominal thickness. Methods: Six passive upper aligners of different brands were adapted to a single printed cast. Each sample was evaluated with high-resolution micro-computed tomography. To investigate aligner thickness and gap width, two-dimensional (2D) analysis was conducted assessing the effects of the following variables: tooth type (central incisor, canine, and first molar), 2D reference points, and aligner type. Data were analyzed and compared using analysis of variance and Tukey's post-hoc tests (p < 0.05). Results: Tooth type, dental region, and aligner type affected both the gap width and aligner thickness. The aligner thickness remained moderately stable across the arch only in the F22. Conclusions: All thermoformed samples displayed smaller aligner thickness and gap width at anterior teeth and both gingival and coronal centers than at posterior teeth and occlusal surfaces.

아말감 와동의 파절에 관한 2차원 유한요소법적 연구 I : 와동 폭의 변화 (A STUDY ON AMALGAM CAVITY FRACTURE WITH TWO DIMENSIONAL FINITE ELEMENT METHOD I : VARIATION OF THE WIDTH OF CAVITY)

  • 김한욱;이정식
    • Restorative Dentistry and Endodontics
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    • 제20권2호
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    • pp.655-669
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    • 1995
  • Restorative procedures can lead to weakening tooth due to reduction and alteration of tooth structure. It is essential to prevent fractures to conserve tooth. Among the several parameters in cavity designs, cavity isthmus is very important. In this study, amalgam 0 cavity was prepared on maxillary first premolar. Two dimensional finite element models were made by serial photographic method and isthmus(1/4, 1/3, 1/2, 2/3 of intercuspal distance) were varied. Three or four-nodal mesh were used for the two dimensional finite element models. The periodontal ligament and alveolar bone surrounding the tooth were excluded in these models. 1S model was sound tooth with no amalgam cavity. B model was assumed perfect bonding between the restoration and cavity wall. Both compressive and tensile forces were distributed directly to the adjacent regions. A load of 500N was applied vertically at the first node from the lingual slope of the buccal cusp tip. This study analysed von Mises stress, 1 and 2 directional normal stress and Y and Z axis translation with FEM software Super SAPII Version 5.2 (Algor Interactive System Co.) and hardware 486 DX2 PC. The results were as :follows : 1. 1S model was slightly different with 1B model in stress distibution. 1S, 2B, 3B, 4B models showed similiar stress distribution. 2. 1S model and four B models showed similiar pattern in Y axis and Z axis translation. 3. 1S model and four B models showed the bending phenomenon in the translation. 4. As increasing of the width of the cavity, experimental group was similiar with the control group in stress distribution. 5. As increasing of the width of the cavity, experimental group was similiar with the control group in Y and Z axis tranlation.

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Analysis on load-bearing contact characteristics of face gear tooth surface wear with installation errors

  • Fan Zhang;Xian-long Peng
    • Computers and Concrete
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    • 제31권2호
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    • pp.163-171
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    • 2023
  • Face gear transmission is widely used in aerospace shunt-confluence transmission system. Tooth wear is one of the main factors affecting its bearing transmission performance. Furthermore, the installation errors of face gear are inevitable. In order to study the wear mechanism of face gear tooth surface with installation errors, based on tooth contact analysis numerical method and Archard wear theory, the UMESHMOTION subroutine in ABAQUS is developed.Combining with Arbitrary Lagrangian-Eulerian adaptive mesh technology, the finite element mesh wear model of abraded face gear pair is established.The preprocessing conditions are set to generate the inp files.Then,the inp files for each corner are imported and batch processed in ABAQUS.The loading tooth contact problem at each rotation angle is solved and the load distribution coefficient among gear tooth, tooth root bending stress, tooth surface contact stress and loaded transmission error are obtained. Results show that the tooth root wear is the most serious and the wear at the pitch cone is close to 0.The wear law of tooth surface along tooth width direction is convex parabola and the wear law along tooth height direction is concave parabola.

유치조기발거후 보극장치물이 치궁발육에 미치는 영향 (Longitudinal Study on Effects of Dfntal Arch Growth in the Case of Using a Space-Maintaier After Primary Tooth Extraction)

  • 손동수
    • 대한치과의사협회지
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    • 제11권4호
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    • pp.277-280
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    • 1973
  • The author observed the changes of dental arch dimensions and compared spae-maintainer group with non-space-maintainer group after primary tooth extraction. The results were as follows 1) The rate of growth of dental arch of expeirmental group in intercanine width and in inter-1st molar width was more rapid than that of the control group. 2) Arch length is almost no dimensions but it was slightly decreased in lower arch. 3) Dental arch growth and tooth eruption were stimulated by space-maintainer appliance, so it is the best way to replace a new appliance at least once a year. 4) It is thought that satisfactory conclusions in this observation must be researched successively until the mixed dentition completes.

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생물학적 폭경을 고려한 보철임상 증례 (Clinical Cases on the Restorative Procedure Preserving the Biologic Width)

  • 김정호
    • 대한심미치과학회지
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    • 제8권1호
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    • pp.28-35
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    • 1999
  • The preservation of a healthy periodontal attachment is the most significant factor in the long-term prognosis of a restored tooth. The 'Biologic Width' is composed of the connective tissue attachment and the epithelial attachment in the dentogingival junction. The violation of the biologic width may result in a progressive inflammatory process and crestal bone loss. So a careful soft tissue management is needed to preserve it for the gingival health and an esthetic restoration. The following clinical cases show the five different situations of the violation of the biologic width and their management.

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정상교합자와 I급 부정교합자에서 치아와 기저골의 관계에 대한 비교 분석 (COMPARATIVE ANALYSIS OF THE RELATIONSHIP BETWEEN BASAL BONE AND TEETH IN NORMAL OCCLUSION AND ANGLE'S CLASS I MALOCCLUSION)

  • 문혜정;경희문;권오원;김정민
    • 대한치과교정학회지
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    • 제22권2호
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    • pp.413-426
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    • 1992
  • 저자는 좋은 교합관계를 유지하기 위한 치아와 기저골과의 관계를 분석하기 위해 정상교합자와 Angle써 I급 부정교합자(비발치군, 발치군)의 경석고 모형상에서 최대치아근원심폭경, 기저악궁폭경 및 기저악궁장경을 계측하고 최대치아근원심폭경 합, 최대치아근원심폭경 합에 대한 기저악궁폭경 비, 최대치아근원심폭경 합에 대한 기저악궁장경 비 및 최대치아근원심폭경 합에 대한 기저악궁폭경과 기저악궁장경합의 비를 산출하여 통계학적으로 분석한 결과 다음과 같은 결과를 얻었다. 1. 최대치아근원심폭경합에 대한 기저악궁폭경 비는 상악에서 정상교합군은 $46.9{\pm}2.6\%$, 비발치군은 $49.4{\pm}3.9\%$, 발치군은 $42.5{\pm}3.3\%$로 나타났으며, 하악에서 정상교합군은 $46.6{\pm}2.4\%$, 비발치군은 $47.5{\pm}4.0\%$, 발치군은 $42.6{\pm}2.6\%$로 나타났다. 2. 최대치아근원심폭경합에 대한 기저악궁장경 비는 상악에서 정상교합군은 $33.4{\pm}1.9\%$, 비발치군은 $33.9{\pm}1.8\%$, 발치군은 $28.7{\pm}2.5\%$로 타나났으며, 하악에사 정상교합군은 $34.4{\pm}4.3\%$, 비발치군은 $36.5{\pm}1.9\%$, 발치군은 $31.5{\pm}2.5\%$로 나타났다. 3. 최대치아근원심폭경합에 대한 기저악궁폭경과 기저악궁장경 합의 비는 상악에서 정상교합군은 $80.3{\pm}3.4\%$, 비발치군은 $83.3{\pm}4.8\%$, 발치군은 $71.2{\pm}4.3\%$로 나타났으며, 하악에서는 정상교합군은 $81.0{\pm}5.2\%$, 비발치군은 $84.0{\pm}5.4\%$, 발치군은 $74.1{\pm}4.1\%$로 나타났다. 4. 최대치아근원심폭경합에 대한 기저악궁폭경 비의 $95\%$ 신뢰구간은 상악에서 정상교합군은 $46.3-47.5\%$, 비발치군은 48.1-50.7, 발치군은 $41.7-43.3\%$로 나타났으며, 하악에서 정상교합군은 $46.1-47.2\%$, 비발치군은 $46.1-48.8\%$, 발치군은 $42.0-43.3\%$로 나타났다. 5. 최대치아근원심폭경합에 대한 기저악궁장경비의 $95\%$신뢰구간은 상악에서 정상교합군은 $32.9-33.8\%$, 비발치군은 $33.3-34.5\%$, 발치군은 $28.1-29.2\%$로 나타났으며, 하악에서 정상교합군은 $33.4-35.4\%$, 비발치군은 $35.8-37.2\%$, 발치군은 $30.9-32.1\%$로 나타났다. 6. 최대치아근원심폭경합에 대한 기저악궁폭경과 기저악궁장경 합의 비의 $95\%$신뢰구간은 상악에서 정상교합군은 $79.5-81.0\%$, 비발치군은 $81.6-84.9\%$, 발치군은 $70.1-72.2\%$로 나타났으며, 하악에서 정상교합군은 $79.8-82.2\%$, 비발치군은 $82.1-85.5\%$, 발치군은 $73.1-75.1\%$로 나타났다. 7. 최대치아근원심폭경합, 기저악궁폭경, 기저악궁장경, 최대치아근원심폭경 합에 대한 기저악궁폭경 비, 최대치아근원심폭경 합에 대한 기저악궁장경 비 및 최대치아근원심폭경 합에 대한 기저악궁폭경과 기저악궁장경 합의 비에서 발치군 남자의 기저악궁장경을 제외하고는 상하악간에 상관관계가 있는 것으로 나타났다.

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상악 전치부 치은선의 평균치에 관한 연구 (Study of Normative Gingival Proportion in Anterior Maxilla)

  • 정민영;임성빈;정진형
    • Journal of Periodontal and Implant Science
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    • 제34권1호
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    • pp.19-28
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    • 2004
  • Tooth is the most important element in esthetic consideration on facial area. Tooth alignment which is in harmony with gingiva, lips, and face is also key element. The purpose of this study was to give a clinical discipline for restoration of gingival contour, which contains a ratio of maxillary 6 anterior teeth, research for gingival contour etc., in case of rehabilitation of maxillary anterior teeth. 300 Dankook university dental school students ,who is their twenties and free from periodontitis, participate in this study. The result was from each 70 males and females who had normal occlusion and tooth alignment. Length, width and length/width ratio of maxillary 6 anterior teeth were 0.74-0.81 in male, 0.81-0.84 in female. There was significant difference between male and female. The most deepest position of gingiva in maxillary central incisor and canine was located in distal part of teeth and maxillary lateral incisor was middle portion. In maxillary central incisors, gingival line of the most deepest point appeared significant difference between male and female (p<0.01) whereas there was no difference in lateral incisors and canines. Distance between interdental papilla apex and the most deepest portion appeared significant difference between male and female. Distance of the deepest position of gingiva is statistically significant except maxillary central incisors and lateral incisors. Standard deviation and mean of the width of labio-lingual were measured in cervical area and there was a significant difference both male and female.(p<0.01) From this result, we could get the mean of maxillary anterior gingival line and these results have great value in clinical guidance in studying maxillary anterior teeth.

치아크기 계측오차에 관한 연구 (A study on the error of tooth size measurements)

  • 심은주;황현식;문재동
    • 대한치과교정학회지
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    • 제29권4호
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    • pp.491-501
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    • 1999
  • 본 연구는 석고모형 분석 중 치아크기 측정시 발생할 수 있는 오차를 줄이고 측정의 재현도와 정확성을 향상시키는데 도움이 될 수 있는 방안을 모색하고자 시행되었다. 치아밀집 치열 특징을 지닌 상하악 20조의 석고모형을 대상으로 하여, 5명의 조사자가 각 치아의 근원심 폭경을 디지털 버니어 캘리퍼스를 사용하여 2주 간격으로 3회 측정하여 실험측정치를 얻은 다음, 측정에 이용된 석고모형을 근원심 접촉점 부위에서 개개 치아로 분리한 후, 마이크로미터를 이용하여 측정한 표준치와 비교$\cdot$분석하여 다음과 같은 결과를 얻었다. 1. 3회 측정에 따른 재현도는 조사자별 치아별로 큰 차이를 나타내지 않았다. 2. 표준치와 비교한 계측오차는 조사자별 또는 치아별로 차이를 보였다. 3. 표준치와의 오차는 전치에서 구치로 갈수록 증가하여 제1대구치에서 가장 큰 차이를 나타내었다. 4. 표준치와 비교시 전반적으로 작게 측정하는 경향을 보였으며 이에 대한 치아별, 조사자별 차이가 두드러졌다. 5. 전반적인 오차 발생 정도는 치아밀집 정도와 유의한 상관성을 보이지 않았다. 이상의 결과는 교정증례 분석시 치아크기 계측오차 발생 가능성의 고려가 필요함을 시사하였다.

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고정자 잇날 페어링을 이용한 고출력 토크 BLDC 전동기의 코깅 토크 및 소음 저감 (Cogging Torque and Acoustic Noise Reduction in High Torque BLDC Motors by Teeth Pairings)

  • 이상민;황상문
    • 대한전기학회논문지:전기기기및에너지변환시스템부문B
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    • 제48권3호
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    • pp.97-103
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    • 1999
  • This paper investigates reduction of acoustic noise and cogging torque in a BLDC motor with larger stator slot open width. Using energy method, cogging torque is analytically determined with airgap MMF function and airgap permeance function and confirmed by FEM analysis. It shows that the cogging torque is firstly governed by NL GNL BNL with the fundamental period of NL, where NL is the least common multiple of the number of slots and the number of poles, GNL, airgap permeance function and BNL, airgap MMF function. It also shows that there exist several tooth width which minimizes the cogging torque, for the motors that smaller slot open width or stator teeth notching is not available. And it proposes a teeth pairing with two different tooth width which can effectively eliminate the cogging torque and thus the acoustic noise. Experimental results show that the proposed teeth pairing reduces the cogging torque by 85% and the acoustic noise by 3.1dB.

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