• Title/Summary/Keyword: Occlusal analysis

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Comparison of the outcomes of three-dimensional finite element analysis under arbitrary and realistic occlusal loading conditions in mandibular posterior region (하악 구치부에서 임의로 부여된 교합과 실제 교합의 삼차원 유한요소해석결과의 비교)

  • Lee, Wonsup;Alom, Ghaith;Kim, Myung-Soo;Park, Young-Seok;Lim, Young-Jun;Kim, Myung-Joo;Kwon, Ho-Beom
    • Journal of Dental Rehabilitation and Applied Science
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    • v.36 no.2
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    • pp.112-120
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    • 2020
  • Purpose: The purpose of this study was to compare the biomechanical outcome in the mandibular posterior region between two different loading conditions by finite element analysis. Materials and Methods: The mandibular posterior teeth model and the implant model were generated for the study. And 2 different types of loading conditions were provided: Arbitrary occlusion and natural occlusion obtained from the digital occlusal analyzer, Accura (Accura, Dmetec Co. Ltd., Seoul, Korea). Total load of 100 N was evenly distributed over arbitrary occlusion points, and 100 N load was differentially distributed over natural occlusion points according to Accura data. The biomechanical outcome was evaluated by the finite element analysis software. Results: The result of finite element analysis showed considerable difference in both von Mises stress pattern and displacement under different loading conditions. Conclusion: In finite element analysis, it is recommended to simulate a realistic occlusal loading pattern that is based on accurate measurement.

An improvement plan of Curriculum in Departments of Dental Technology (치기공과 교육과정의 개선방안)

  • Bae, Bong-Jin;Lee, Hwa-Sik;Park, Myung-Ho
    • Journal of Technologic Dentistry
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    • v.31 no.4
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    • pp.55-66
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    • 2009
  • This research collected the curriculum for Dental Technology from a total of 20 schools --3-year colleges and 4-year colleges-- all in Korea. And we analyzed the average credits of subjects from students. As a result of this analysis, we get the conclusion below: 1. In the arithmetic mean of the major basis subjects which graduates and undergraduates answered about each subjects; Seminar, Dental morphology I II, Dental morphology practice I II, and Dental devices & instruments don't have many credits. And averages of the major application subjects credits which are Implants(especially low), Occlusal anatomy practice I II, Dental ceramics practice I II, and Dental ceramics practice are low, mostly have a converged tendency in high points. 2. In an analysis of the correlation which is based on the major basis subjects: Dental esthetic, oral anatomy I II, Dental materal practice III, Dental casting pracedure, Oral hygiene, Health & medical law, Management administration, and Medical terminology have a meaningful difference. (${\rho}$ < 0.05) 3. In an analysis of the correlation which is based on the major application subjects; Crown and bridge prosthodontics practice IV, Complete denture prosthodontics I II III, Complete denture prosthodontics practice I II III, Dental ceramics I II, Dental ceramics practice I II, Dental ceramics practice IIII, Occlusal anatomy I II, Occlusal anatomy practice I, Operative dentistry laboratory technology I, Operative dentistry laboratory technology practice II, Dental attachment laboratory technology practice, Implants, and Dental laboratory clinical practice have meaningful difference. (${\rho}$ < 0.05) 4. In an analysis of the correlation which is based on the ratio of a theory to an actual training; 40:60(38.57%) is the highest, followed by 30:70(30.04%), 50:50(23.32%), 60:40(5.83%), and 70:30(2.24%). These have meaningful difference. (${\rho}$ < 0.05) 5. In an analysis of the correlation which is based on the distinction of sex: Partial denture prosthodontics practice I II III, Complete denture prosthodontics I II III, Complete denture prosthodontics practice I II III, Occlusal anatomy practice I II, Implants, Medical terminology have meaningful difference. (${\rho}$ < 0.05) For the purpose of training entrepreneurs of middle standing who is required by a future society, Department of Dental Technology's Curriculum need to be managed with planning a curriculum which reflects opinions of graduates, undergraduates and a society, and also are considered not focusing on a supplier but focusing on a user.

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A CEPHALOMETRIC STUDY BY DOWNS ANALYSIS IN THE CHILDREN WITH NORMAL OCCLUSION (정상교합아동의 Downs 분석법에 의한 두부방사선 계측학적 연구)

  • Choi, Nam-Ki;Jeong, Byung-Cho;Yang, Kyu-Ho
    • Journal of the korean academy of Pediatric Dentistry
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    • v.29 no.3
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    • pp.295-303
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    • 2002
  • This study was performed to establish the cephalometric standards in Downs analysis and to compare them with other races. The lateral cephalograms of 88 Korean children (47 boys, 41 girls) with normal occlusion and acceptable profile between 7 and 11 years of age were taken and Downs analysis was done. Results were as follows: 1. Norms of Korean boys, girls and both sexes at 7, 9, 11 years of age by Downs analysis were established. 2. There were no statistically significant differences between boys and girls about ten measurements in each group, but significant differences in the occlusal plane angle, lower 1 to occlusal plane angle, interincisal angle, upper 1 to APog plane among 3 groups(p<0.05)(p<0.01). 3. Facial angle, AB plane angle, Y-axis, lower 1 to occlusal plane angle and lower 1 to mandibular plane angle showed increasing tendency whereas angle of convexity, mandibular plane angle, occlusal plane angle and interincisal angle did decreasing tendency according to aging. 4. In comparison among races, measurements in Korean children were generally larger than those of Caucasian and Greek except for small interincisal angle, but Korean were similar to Japanese, Chinese, Israeli, Negro about all measurements.

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Factors Influencing the Duration of Occlusal Appliance Treatment for Patients with Temporomandibular Joint Internal Derangement

  • Lee, So-Youn;Byun, Jin-Seok;Jung, Jae-Kwang;Choi, Jae-Kap
    • Journal of Oral Medicine and Pain
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    • v.41 no.3
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    • pp.110-117
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    • 2016
  • Purpose: The purpose of this study is to determine factors influencing the duration of occlusal appliance (OA) treatment for patients with temporomandibular joint (TMJ) internal derangement. Methods: Ninety patients were included for this study, who satisfied the following including criteria: (i) those who were diagnosed as disc displacement of TMJ by taking magnetic resonance imaging (MRI) and (ii) those who were finished OA treatment. The subjects were classified into three groups according to the period of OA treatment: (i) early response group (<6 months), (ii) moderate response group (6 months-1 year), and (iii) delayed response group (>1 year). Demographic data, data from chief complaints and past history of temporomandibular disorder, data from clinical examination and diagnostic imaging including panoramic view and TMJ MRI were compared among groups. One-way ANOVA and chi-square analysis were used to test statistical significance. Results: There were no significant differences in demographic data, data from chief complaints and TMJ imaging. However, only the prevalence of oral parafunctional habits including bruxism, clenching, and unilateral chewing showed significant differences among groups. Conclusions: Oral parafunctional habits could be factors to influence the duration of OA treatment in the patients with TMJ internal derangement.

TWO-DIMENSIONAL FINITE ELEMENT ANALYSIS ON THE EFFECT OF INTERFACE CONDITION AND RETENTION GROOVE IN CLASS V COMPOSITE RESIN RESTORATION (5급 복합레진충전된 치아에 있어서의 계면조건과 유지구의 영향에 대한 2차원유한요소법적 연구)

  • Cho, Byeong-Hoon;Yoo, Hyeon-Mee;Kim, Dong-Ho
    • Restorative Dentistry and Endodontics
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    • v.23 no.2
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    • pp.639-646
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    • 1998
  • To evaluate the effect of interface conditions and retention grooves in the Class V composite resin restoration of the maxillary first premolar, the distribution of the values of stress and displacement was analyzed with the two-dimensional finite element method. The results were obtained as follows : 1. Boundary elements and Stiffness values could be used as the interface parameters in the, finite element method. 2. The amount of restriction of the displacement at the cervical margin by placing a retention groove at the cervical wall was about three times as high as that by placing a retention groove at the occlusal wall. 3. Because of the relative amount of tensile components of the stress values in the bucco-lingual direction, the possibility of dislocation of the restoration was much higher at the cervical margin than at the occlusal margin. 4. It might be recommended that both occlusal and cervical retention grooves be used routinely, but if one, it be placed at the cervical wall.

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RECOGNITION OF MALOCCLUSION AND ORTHODONTIC TREATMENT NEED OF 7~18 YEAR-OLD KOREAN ADOLESCENT (7~18세 청소년의 부정교합에 대한 인식과 교정치료 수요에 관한 연구)

  • Lee, Shin-Jae;Suhr, Cheong-Hoon
    • The korean journal of orthodontics
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    • v.24 no.2
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    • pp.367-394
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    • 1994
  • The purpose of this study was to evaluate self perception of occlusal status and recognition for orthodontic treatment as well as the prevalence of orthodontic treatment need objectively and subjectively. 3979 (male 2107, female 1872) school students of age 7~18 were analyzed by questionnaire and clinical examination and the results were as follows, 1. Perception of occlusal status on one's own was more generous than that of orthodontist's and it was affected by the factors such as age, patterns of malocclusion. 2. Recogniuon of subjective need for orthodontic treatment was more generous than that of objective need for the treatment, and factors such as age and sex of patient, parents' age and rate of education, income, occupation, classification of malocclusion and regional discrepancy were influenced. 3. Negative aspect of orthodontic treatment was influenced by the environmental factors. 4. A survey of want for orthodontic treatment showed one's alteration in recognition of the occlusal status with age and esthetic component was much more emphasized than functional component. 5. The multivariate discriminanat analysis for orthodontic treatment group showed that mother's rate of education, classification of malocclusion, demographic characteristics were critical in the determination of treatment group. 6. Test of inter-examiner reliability showed moderate coincidence.

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Quantitative evaluation and affecting factors of post-treatment relapse tendency (교정치료 후 나타나는 재발 경향에 대한 정량적 평가와 영향을 미치는 요소에 대한 연구)

  • Son, Woo-Sung;Cha, Kyung-Suk;Chung, Dong-Hwa;Kim, Tae-Woo
    • The korean journal of orthodontics
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    • v.41 no.3
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    • pp.154-163
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    • 2011
  • Objective: The purpose of this study was to quantitatively evaluate relapse tendency after orthodontic treatment and determine the contributing factors by using the American Board of Orthodontics objective grading system (ABO-OGS). Methods: The subjects were 80 patients with more than 2 years of retention period after completing orthodontic treatment at the dental hospitals of Busan University, Kyunghee University, and Dankook University. The posttreatment (T2) and post-retention (T3) ABO-OGS measurements were analyzed in relation to age, gender, Angle's classification, extraction, retention period, and pretreatment condition (initial peer assessment rating (PAR) index, T1) by multiple regression analysis. Results: Among the 7 ABO-OGS criteria, alignment worsened but occlusal contact and interproximal contact improved in T3, but not in T2 ($p$ < 0.01). The 4 other criteria showed no significant differences. Multiple regression analysis showed that alignment, occlusal relationship, overjet, and interproximal contact were significant linear models, but with a low explanation power. Age, gender, Angle's classification, extraction, retention period, and pretreatment condition (initial PAR index, T1) had little influence on the ABO-OGS changes between T3 and T2. Conclusions: An orthodontist's understanding of posttreatment relapse tendency can be useful in diagnosis and during patient consultation.

Analysis of Primary Molar Relationship using Digital Photograph (구강 내 사진을 이용한 유구치 관계에 대한 분석)

  • Lim, Soyoung;Kang, Chung-min;Hwang, Dong hwan;Choi, Hyung-jun;Kim, Seong-Oh
    • Journal of the korean academy of Pediatric Dentistry
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    • v.47 no.1
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    • pp.36-43
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    • 2020
  • The aim of this study was to assess the occlusal relationships of primary dentition of Korean preschool children in Hwaseong city. Total 444 children of age group between 2 and 5 years were selected. One pediatric dentist took intraoral photos of children. Evaluation and categorization of the primary molar relationships were done by single examiner. Statistical analysis was performed with Pearson chi-squared test. Total 389 samples, which is consisted of 185 boys, 204 girls were satisfied with inclusion criteria. Bilateral mesial step was seen in 61.7%. Bilateral flush terminal plane was seen in 15.4%. When the primary molar relations of the right and left sides were not the same, the combination of the mesial step and flush terminal plane was 14.7%. The present study provides insight into occlusal relationships in the primary dentition of 2 - 5 years old of Korean children in Hwaseong city. Pediatric dentists should understand occlusal relationships of primary dentition for establishment of appropriate treatment strategies and occlusal guidance.

EFFECT OF RESTORATION TYPE ON THE STRESS DISTRIBUTION OF ENDODONTICALLY TREATED MAXILLARY PREMOLARS; THREE-DIMENSIONAL FINITE ELEMENT STUDY (수복물의 종류가 근관치료된 상악 제2소구치의 응력분포에 미치는 영향: 3차원 유한요소법적 연구)

  • Jung, Heun-Sook;Kim, Hyeon-Cheol;Hur, Bock;Kim, Kwang-Hoon;Son, Kwon;Park, Jeong-Kil
    • Restorative Dentistry and Endodontics
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    • v.34 no.1
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    • pp.8-19
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    • 2009
  • The purpose of this study was to investigate the effects of four restorative materials under various occlusal loading conditions on the stress distribution at the CEJ of buccal. palatal surface and central groove of occlusal surface of endodontically treated maxillary second premolar, using a 3D finte element analysis. A 3D finite element model of human maxillary second premolar was endodontically treated. After endodontic treatment, access cavity was filled with Amalgam, resin, ceramic or gold of different mechanical properties. A static 500N forces were applied at the buccal (Load-1) and palatal cusp (Load-2) and a static 170N forces were applied at the mesial marginal ridge and palatal cusp simultaneously as centric occlusion (Load-3). Under 3-type Loading condition, the value of tensile stress was analyzed after 4-type restoration at the CEJ of buccal and palatal surface and central groove of occlusal surface Excessive high tensile stresses were observed along the palatal CEJ in Load-1 case and buccal CEJ in Load-2 in all of the restorations. There was no difference in magnitude of stress in relation to the type of restorations. Heavy tensile stress concentrations were observed around the loading point and along the central groove of occlusal surface in all of the restorations. There was slight difference in magnitude of stress between different types of restorations. High tensile stress concentrations around the loading points were observed and there was no difference in magnitude of stress between different types of restorations in Load-3.