• Title/Summary/Keyword: Angulation

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In vitro physical, chemical, and biological evaluation of commercially available metal orthodontic brackets

  • Kim, Joo Hyoung;Cha, Jung Yul;Hwang, Chung Ju
    • The korean journal of orthodontics
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    • v.42 no.6
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    • pp.297-306
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    • 2012
  • Objective: This in vitro study was undertaken to evaluate the physical, chemical, and biological properties of commercially available metal orthodontic brackets in South Korea, because national standards for these products are lacking. Methods: Four bracket brands were tested for dimensional accuracy, (manufacturing errors in angulation and torque), cytotoxicity, composition, elution, and corrosion: Archist (Daeseung Medical), Victory (3M Unitek), Kosaka (Tomy), and Confidence (Shinye Odontology Materials). Results: The tested rackets showed no significant differences in manufacturing errors in angulation, but Confidence brackets showed a significant difference in manufacturing errors in torque. None of the brackets were cytotoxic to mouse fibroblasts. The metal ion components did not show a regular increasing or decreasing trend of elution over time, but the volume of the total eluted metal ions increased: Archist brackets had the maximal Cr elution and Confidence brackets appeared to have the largest volume of total eluted metal ions because of excessive Ni elution. Confidence brackets showed the lowest corrosion resistance during potentiodynamic polarization. Conclusions: The results of this study could potentially be applied in establishing national standards for metal orthodontic brackets and in evaluating commercially available products.

A Case of Bronchial Obstruction Due to Bronchial Angulation after Upper Lobectomy (엽절제술 후 기관지 꺾임에 의하여 발생한 기관지 폐쇄 1예)

  • Lee, Ho-Su;Yim, Ji-Hye;Kim, Woo-Jin;Shin, Ji-Hoon;Oh, Yeon-Mok
    • Tuberculosis and Respiratory Diseases
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    • v.66 no.3
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    • pp.216-219
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    • 2009
  • A bronchial obstruction of the remaining lung is a rare complication of thoracic surgery. We report a case of this rare complication after a right upper lobectomy due to a giant bulla. Post-resectional angulation of the bronchus intermedius caused the bronchial obstruction. An intrabronchial stent was inserted into the bronchus intermedius, which relieved the obstruction.

FRICTIONAL FORCES IN THE FIXED ORTHODONTIC APPLIANCE DURING TOOTH MOVEMENT (고정성 교정장치를 이용한 치아이동시 발생되는 마찰력)

  • Cho, Myeong-Sook;Kim, Jong-Chul
    • The korean journal of orthodontics
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    • v.20 no.2
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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.

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Assessment of maxillary third molars with panoramic radiography and cone-beam computed tomography

  • Jung, Yun-Hoa;Cho, Bong-Hae
    • Imaging Science in Dentistry
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    • v.45 no.4
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    • pp.233-240
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    • 2015
  • Purpose: This study investigated maxillary third molars and their relation to the maxillary sinus using panoramic radiography and cone-beam computed tomography (CBCT) Materials and Methods: A total of 395 maxillary third molars in 234 patients were examined using panoramic radiographs and CBCT images. We examined the eruption level of the maxillary third molars, the available retromolar space, the angulation, the relationship to the second molars, the number of roots, and the relationship between the roots and the sinus. Results: Females had a higher frequency of maxillary third molars with occlusal planes apical to the cervical line of the second molar (Level C) than males. All third molars with insufficient retromolar space were Level C. The most common angulation was vertical, followed by buccoangular. Almost all of the Level C molars were in contact with the roots of the second molar. Erupted teeth most commonly had three roots, and completely impacted teeth most commonly had one root. The superimposition of one third of the root and the sinus floor was most commonly associated with the sinus floor being located on the buccal side of the root. Conclusion: Eruption levels were differently distributed according to gender. A statistically significant association was found between the eruption level and the available retromolar space. When panoramic radiographs showed a superimposition of the roots and the sinus floor, expansion of the sinus to the buccal side of the root was generally observed in CBCT images.

THE STUDY ON THE POSITION OF THE MANDIBULAR FORAMEN IN KOREAN CHILDREN (한국인(韓國人) 아동(兒童)의 하악공(下顎孔) 위치(位置)에 관(關)한 X선학적(線學的) 고찰(考察))

  • Baek, Byeong-Joo
    • Journal of the korean academy of Pediatric Dentistry
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    • v.4 no.1
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    • pp.24-27
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    • 1977
  • The Author measured the position of the mandibular foramen with oblique cephalography in 43 5-aged, and 44 7-aged Korean children. The results of the studies were as follows; 1) The distance from the post. occlusal plane to the mandibular foramen was $3.16{\pm}1.22mm$. in age 5 and $1.86{\pm}1.50mm$. in age7 to the below. 2) The meeting point of the occlusal plane and anterior of the ramus to the mandibular foramen was $16.56{\pm}2.18mm$. in age5 and $16.88{\pm}2.69mm$. in age7. 3) The angulation between the occlusal plane and the line connecting the mandibular foramen and the meeting point of anterior border of the ramus with occlusal plane was $12.70{\pm}4.31^{\circ}$ in age5 and $8.27{\pm}5.36^{\circ}$ in age7 to the below. 4) % depth was $56.93{\pm}5.65%$ in age 5 and $53.20{\pm}7.12%$ in age 7. 5) The price of distance and angulation showed significant results at 0.01 level in KOLMOGOROV-SMIRNOV (TWO-SAMPLE) TEST.

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Kinematic Comparative Analysis of Short Turns between Skilled and Unskilled Alpine Skiers

  • Jo, Hyun Dai
    • Korean Journal of Applied Biomechanics
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    • v.29 no.4
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    • pp.219-226
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    • 2019
  • Objective: The purpose of this study is to provide a better understanding of short turn mechanism by describing short turns after kinematic analysis and provide skiers and winter sports instructors with data through which they are able to analyze right postures for turns in skiing in a systematic, rational and scientific manner. Method: For this, a mean difference of kinematic variables (ski-hip angle, ski-shoulder twist angle, pole checking angle, the center of gravity (CG) displacement, trunk forward lean angle) was verified against a total of 12 skiers (skilled and unskilled, 6 persons each), regarding motions from the up-start to down-end points for short turns. Results: There was no difference in a ski-hip twist angle. The ski-shoulder twist angle was large at the up-start point while a pole-checking angle was high at the down-end point in skilled skiers. Concerning the horizontal displacement of CG, skilled skiers were positioned on the right side at the upstart point. No significant difference was observed in the trunk forward lean angle. Conclusion: According to the ski-shoulder twist angle and CG horizontal displacement results, the upper body should be kept leant toward the pole. In addition, big turns should be made via edging and angulation. During pole checking, the hand holding the pole should be thrown and released toward a vector direction of the forearm.

The Association of Ponticulus Posticus & Elongated Styloid Process with Headaches

  • Sharma, Shivani;Nagaraju, Rakesh;Sharma, Shweta
    • Journal of Oral Medicine and Pain
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    • v.43 no.3
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    • pp.77-83
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    • 2018
  • Purpose: The present study was designed to investigate the association of ponticulus posticus (PP) and elongated styloid process (ESP) with headaches. Methods: Analysis of head and neck cone beam computed tomography samples from the archives of the Department of Oral Radiology was done for the presence of partial or complete PP and ESP length, type, thickness, mediolateral angulation, anterioposterior angulation (horizontal & vertical), lateral or medial curvature. This was followed by personal & telephonic questionnaires to the subjects for the evaluation of the presence of headaches & other associated symptoms. Results: Among 134 subjects, 62 subjects (46.3%) presented with headache and 72 subjects (53.7%) did not have any headache. On further analysing the total 62 subjects with headache, it was found out that 31 subjects (50.0%) of them had ESP and PP both, 16 subjects (25.8%) had only ESP, and 15 subjects (24.2%) had only PP. A strong association was present between headache and presence of PP & ESP individually and together. Conclusions: All health care professionals dealing with the head and neck pain disorders should also consider the presence of ESP & PP during diagnosis and treatment.

Crown-root angulations of the maxillary anterior teeth according to malocclusions: A cone-beam computed tomography study in Korean population

  • Lee, Kyoung-Hoon;Choi, Dong-Soon;Jang, Insan;Cha, Bong-Kuen
    • The korean journal of orthodontics
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    • v.52 no.6
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    • pp.432-438
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    • 2022
  • Objective: To compare crown-root angulations of the permanent maxillary anterior teeth in skeletal Class I, Class II, and Class III Korean malocclusion patients using cone-bean computed tomography (CBCT) images. Methods: Sixty CBCT images were collected from orthodontic patients archive based on skeletal Class I (0˚< A point-nasion-B point angle [ANB] < 4˚), Class II (ANB ≥ 4˚), and Class III (ANB ≤ 0˚) to have 20 samples in each group. Mesiodistal crown-root angulation (MDCRA) and labiolingual crown-root angulation (LLCRA) were evaluated after orientation of images. Crown-root angulations were compared among Class I, Class II, and Class III groups and among the maxillary anterior teeth in each group. Results: LLCRAs of the maxillary central incisor and the lateral incisor were significantly lower in Class III group than those in Class I group. However, those of the canine showed no significant differences among groups. MDCRAs of the maxillary anterior teeth did not significantly differ among groups either. Conclusions: Our results suggest that skeletal Class III malocclusion might affect LLCRA of the maxillary incisors, especially the central incisor.

The relationship between condyle position, morphology and chin deviation in skeletal Class III patients with facial asymmetry using cone-beam CT (안면비대칭을 동반한 골격성 III급 부정교합자에서 하악 과두의, 위치 형태와 이부 편위의 관계: cone-beam CT를 이용한 연구)

  • Lee, Bo-Ram;Kang, Dae-Keun;Son, Woo-Sung;Park, Soo-Byung;Kim, Seong-Sik;Kim, Yong-Il;Lee, Kyung-Min
    • The korean journal of orthodontics
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    • v.41 no.2
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    • pp.87-97
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    • 2011
  • Objective: Facial asymmetry is usually evaluated from the difference in length and angulation of the maxilla and mandible. However, asymmetric position or shape of the condyle can also affect the expression of asymmetry. The purpose of this study was to evaluate the correlation between condylar asymmetry and chin point deviation in facial asymmetry. Methods: Cone-beam CT images of fifty adult skeletal Class III patients were studied. Thirty patients who had more than 4 mm menton deviation were categorized in the asymmetric group. Twenty patients with less than 4 mm menton deviation were assigned to the symmetric group. Anteroposterior and transverse condyle positions were evaluated from the cranial base. The greatest mediolateral diameter (GMD) of the condyle in the axial plane and angulation to the coronal plane were measured. The height and volume of the condyles were evaluated. Results: The symmetric group had no statistical difference between both condyles in position, angulation, GMD, height and volume. In the asymmetric group, the non-deviated side condyle was larger in GMD, height and volume than the deviated side. There was no statistical difference in condyle position and angulation. The GMD, height difference and condylar volume ratio (non-deviated/deviated) were positively correlated with chin deviation. From the linear regression analysis, condylar volume ratio was a significant factor affecting chin deviation. Conclusions: These findings suggests that the non-deviated side condyle is larger than the deviated side. In addition, condylar asymmetry can affect the expression of facial asymmetry.

Patient Radiation Exposure Dose Evaluation of Whole Spine Scanography Due to Exposure Direction (Whole Spine Scanography의 검사방향에 따른 환자 선량 평가)

  • Kim, Jung-Su;Seo, Deok-Nam;Kwon, Soon-Mu;Kim, Jung-Min
    • Journal of radiological science and technology
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    • v.38 no.1
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    • pp.1-6
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    • 2015
  • Whole spine scanography (WSS) is a radiological examination that exposes the whole body of the individual being examined to x-ray radiation. WSS is often repeated during the treatment period, which results in a much greater radiation exposure than that in routine x-ray examinations. The aims of the current study were to evaluate the patient dose of WSS using computer simulation, image magnification and angulation of phantom image using different patient position. We evaluated the effective dose(ED) of 23 consecutive patients (M : F = 13:10) who underwent WSS, based on the automatic image pasting method for multiple exposure digital radiography. The Anterior-Posterior position(AP) and Posterior-Anterior position( PA) projection EDs were evaluated based on the PC based Monte Carlo simulation. We measured spine transverse process distance and angulation using DICOM measurement. For all patient, the average ED was 0.069 mSv for AP position and 0.0361 mSv for PA position. AP position calculated double exposure then PA position. For male patient, the average ED was 0.089 mSv(AP) and 0.050 mSv(PA). For female patient, the average ED was 0.0431 mSv(AP) and 0.026 mSv(PA). The transverse process of PA spine image measured 5% higher than AP but angulation of transverse process was no significant differences. In clinical practice, just by change the patient position was conformed to reduce the ED of patient. Therefor we need to redefine of protocol for digital radiography such as WSS. whole spine scanography, effective dose, patient exposure dose, exposure direction. protocol optimization.