• Title/Summary/Keyword: Bolton ratio

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A study on the anterior tooth size discrepancies among orthodontic patients with varying malocclusions (부정교합자의 전치부 치아크기 부조화에 관한 연구)

  • Kim, Hyeok-Soo;Shim, Hae-Young;Nahm, Dong-Seok
    • The korean journal of orthodontics
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    • v.35 no.6 s.113
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    • pp.420-432
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    • 2005
  • Bolton analysis is widely used to predict tooth size discrepancy. but its accuracy has been challenged. The purpose of this study was to describe true anterior tooth size discrepancies among orthodontic patients and to evaluate the factors that affect true anterior tooth size discrepancies. The subjects consisted of 80 patients with varying malocclusions (Class I. Class II. Class III. and Class III surgery) who were treated orthodontically. Pre-treatment models. set-up models from post-treatment models. and lateral cephalometric radiographs were analyzed The results were as follows. The means. the standard deviations. and ranges of anterior Bolton ratio in the present study were somewhat higher than those of Bolton's samples and Korean normal samples. The number of patients showing maxillary deficiency was larger than that of patients showing maxillary excess in view of true anterior discrepancies. There was a significant difference between anterior Bolton discrepancy from pre-treatment models and true anterior discrepancy from set-up models (p < 0.05) There was no significant difference in true anterior discrepancies among malocclusion groups (p > 0.05). And there was also no significant difference between the male and female groups (p> 0.05). Overbite and the incisal edge thickness of maxillary anterior teeth have little relationship with true anterior discrepancies. Multiple regression analysis showed that true anterior discrepancy was mainly determined by anterior Bolton ratio, upper incisor to occlusal plane angle after treatment. interincisal angle after treatment. and upper right lateral incisor width.

The effect of premolar extractions on tooth-size discrepancy in malocclusion patients (Original Article 1 - 부정교합과 차등적 소구치 발치가 치아 크기 부조화에 미치는 영향)

  • Kim, Hee-Hun;Sung, Sang-Jin;Moon, Yoon-Shik
    • The Journal of the Korean dental association
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    • v.48 no.3
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    • pp.196-204
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    • 2010
  • To establish the ideal occlusal relationship, the values of tooth size and ratio must be in a normal range. In this study, the means and standard deviations of Bolton's anterior ratio and overall ratio using mesiodistal dimensions of teeth measured on diagnostic models of 334 Korean malocclusion patients were calculated and differences in Bolton ratio according to the groups of malocclusion patients were studied. Also the changes that can occur in overall ratio before and after hypothetical tooth extractions were observed. The results are as follows. 1. The mean anterior ratio of Korean malocclusion patients was $78.0\;{\pm}\;2.69%$, and the mean overall ratio was $91.56\;{\pm}\;2.28%$. 2. The largest value of tooth size ratio could be found in Class III group, followed by Class I and Class II groups in order. However there was no statically significant difference. 3. The values of overall ratio reduced significantly after premolar extractions in all malocclusion groups, which was much more significant in the extraction of upper second premolar and lower first premolar(U5L4) or upper second premolar and lower second premolar(U5L5). 4. The values of overall ratio reduced significantly after premolar extractions in all 3 groups divided based on Bolton ratio, which was much more significant in the extraction of upper second premolar and lower first premolar(U5L4) or upper second premolar and lower second premolar(U5L5).

Principles and considerations of orthodontics for Prosthodontic treatment (심미보철치료를 위한 교정치료의 원칙과 고려사항)

  • Chang, Won-Gun
    • The Journal of the Korean dental association
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    • v.56 no.9
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    • pp.503-511
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    • 2018
  • Outcome of esthetic ceramic restorations are affected by tooth size, gingival contour, occlusal relationship, etc. For this reason, demand of orthodontic treatment before esthetic ceramic restoration is increasing. If a Bolton ratio discrepancy, a problem of the maxillary incisor's vertical position, a problem of inclination of anterior teeth, a pathogenic occlusion is existed, a pre-prosthodontic orthodontics should be accomplished. These problems can be satisfactory only after the prosthetic treatment is performed after orthodontic treatment. When orthodontic treatment is given, it should be treated with the following principle. 1. Treat it in the direction of functioning occlusion. 2. Keep the patient's stable occlusal scheme. 3. Treat the teeth by considering the average tooth size and Bolton ratio. Ortho-Prostho combined treatment with optimal treatment plan can lead a patient's function, esthetics, and long-term stability.

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Artificial neural network model for predicting sex using dental and orthodontic measurements

  • Sandra Anic-Milosevic;Natasa Medancic;Martina Calusic-Sarac;Jelena Dumancic;Hrvoje Brkic
    • The korean journal of orthodontics
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    • v.53 no.3
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    • pp.194-204
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    • 2023
  • Objective: To investigate sex-specific correlations between the dimensions of permanent canines and the anterior Bolton ratio and to construct a statistical model capable of identifying the sex of an unknown subject. Methods: Odontometric data were collected from 121 plaster study models derived from Caucasian orthodontic patients aged 12-17 years at the pretreatment stage by measuring the dimensions of the permanent canines and Bolton's anterior ratio. Sixteen variables were collected for each subject: 12 dimensions of the permanent canines, sex, age, anterior Bolton ratio, and Angle's classification. Data were analyzed using inferential statistics, principal component analysis, and artificial neural network modeling. Results: Sex-specific differences were identified in all odontometric variables, and an artificial neural network model was prepared that used odontometric variables for predicting the sex of the participants with an accuracy of > 80%. This model can be applied for forensic purposes, and its accuracy can be further improved by adding data collected from new subjects or adding new variables for existing subjects. The improvement in the accuracy of the model was demonstrated by an increase in the percentage of accurate predictions from 72.0-78.1% to 77.8-85.7% after the anterior Bolton ratio and age were added. Conclusions: The described artificial neural network model combines forensic dentistry and orthodontics to improve subject recognition by expanding the initial space of odontometric variables and adding orthodontic parameters.

A STATISTICAL STUDY ON THE PLASTER CAST ANALYSIS OF THE CHILDREN AMONG HEALTHY DENTITION CONTESTANTS II (건치아동의 경석고모형 분석에 관한 통계학적 연구 II)

  • Lee, Sang-Hoon
    • Journal of the korean academy of Pediatric Dentistry
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    • v.23 no.2
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    • pp.365-374
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    • 1996
  • The prupose of this study was to obtain standard measurements of the tooth size, Bolton ratio, width and length of dental arch and basal arch, overbite and overjet of the children who have normal dentition. The plaster cast of 97 children(47 boys and 50 girls) among the contestants in 1992, 1994, 1995 Healthy Dentition contest in Seoul were measured and following results were obtained. 1. Means and standard deviations of the mesio-distal maximum width of the permanent teeth, Bolton ratio, width and length of the dental arch and basal arch of the upper and lower dentition and overbite and overjet of the children were obtained. 2. Mesio-distal width of the teeth, width and length of the dental arch and basal arch of the upper and lower dentition of the boys were larger than those of the girls. 3. Bolton Overall ratio, Anterior ratio and overjet of the boys were larger than those of the girls and overbite of the boys were smaller than those of the girls, but no significant differences were noted between the boys and the girls(p>0.05). 4. In the comparision of the Healthy Dentition Contestants with Korean adults of Shur, all teeth of the Contestants were larger than those of Korean adults, especially upper and lower bicuspids(p<0.01). In the comparision of the Healthy Dentition Contestants with Caucasians, all teeth except upper and lower central incisor and upper first molar of the contestants were larger than those of Caucasians(p<0.05).

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Validity of Arch Relationship Measurements in Digital Dental Models (디지털 치열 모형에서 악궁 관계 지표 측정의 타당성)

  • Ryu, Jiin;Yang, ByoungEun;Lee, Hyelim
    • Journal of the korean academy of Pediatric Dentistry
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    • v.49 no.1
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    • pp.14-24
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    • 2022
  • The aim of the present study is to evaluate the validity of orthodontic measurements including tooth width, Bolton ratio, overjet and overbite on the digital dental models. Dental models of the subjects aged 12 to 18 were obtained in 3 different forms, which were conventional stone model, digital model created with Freedom HD model scanner, and digital model produced with CS3600 intraoral scanner. After measurements were made on the models, reliability and reproducibility of the measurements were evaluated by using intraclass correlation coefficient, while validity was assessed with paired t-test. As a result, significant reliability and reproducibility were verified, with intraclass correlation coefficient exceeding 0.750 in all groups. Measurements of the model scanned group showed an adequate validity in overall and anterior Bolton ratio, overjet, and overbite. Intraoral scanned models showed an adequate validity in anterior Bolton ratio, and overjet. Measurement on intraoral scanned digital models can be considered as an alternative for young children who have difficulty in taking impression. Furthermore, careful considerations on measurement error should be made in clinical situations.

Three-dimensional comparison of 2 digital models obtained from cone-beam computed tomographic scans of polyvinyl siloxane impressions and plaster models

  • Park, Jin-Yi;Kim, Dasomi;Han, Sang-Sun;Yu, Hyung-Seog;Cha, Jung-Yul
    • Imaging Science in Dentistry
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    • v.49 no.4
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    • pp.257-263
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    • 2019
  • Purpose: This study was performed to evaluate the dimensional accuracy of digital dental models constructed from cone-beam computed tomographic (CBCT) scans of polyvinyl siloxane (PVS) impressions and cast scan models. Materials and Methods: A pair of PVS impressions was obtained from 20 subjects and scanned using CBCT (resolution, 0.1 mm). A cast scan model was constructed by scanning the gypsum model using a model scanner. After reconstruction of the digital models, the mesio-distal width of each tooth, inter-canine width, and inter-molar width were measured, and the Bolton ratios were calculated and compared. The 2 models were superimposed and the difference between the models was measured using 3-dimensional analysis. Results: The range of mean error between the cast scan model and the CBCT scan model was -0.15 mm to 0.13 mm in the mesio-distal width of the teeth and 0.03 mm to 0.42 mm in the width analysis. The differences in the Bolton ratios between the cast scan models and CBCT scan models were 0.87 (anterior ratio) and 0.72 (overall ratio), with no significant difference (P>0.05). The mean maxillary and mandibular difference when the cast scan model and the CBCT scan model were superimposed was 53 ㎛. Conclusion: There was no statistically significant difference in most of the measurements. The maximum tooth size difference was 0.15mm, and the average difference in model overlap was 53 ㎛. Digital models produced by scanning impressions at a high resolution using CBCT can be used in clinical practice.

Variation of Undrained Shear Behavior with Consolidation Stress Ratio of Nakdong River Sand (압밀응력비에 따른 낙동강모래의 비배수전단거통 특성)

  • 김영수;정성관;송준혁;정동길
    • Journal of the Korean Geotechnical Society
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    • v.19 no.4
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    • pp.83-93
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    • 2003
  • This research, in order to study the effects of initial shear stress of anisotropically consolidated sand that has 0.558% fines, performed several undrained static and dynamic triaxial test. To simulate the real field conditions, loose and dense samples were prepared. Besides, the cyclic shear strength of Nakdong River sand under various combinations of initial static shear stress, stress path, pore water pressure and residual strength relationship was studied. By using Bolton's theory, peak internal friction angle at failure which has considerable effects on the relative density and mean effective stress was determined. In p'- q diagram, the phase transformation line moves closer to the failure line as the specimen's initial anistropical consolidation stress increases. Loose sands were more affected than dense sands. The increase of consolidation stress ratio from 1.4 to 1.8 had an effect on liquefaction resistance strength resulting from the increase of relativity density, and showed similar CSR values in dense specimen condition.

A study of Korean Norm about tooth size and ratio in Korean adults with normal occlusion (한국성인 정상교합자의 치아크기와 비율에 관한 연구)

  • Kim, Dae-Sik;Kim, Young-Jun;Choi, Jae-Hoon;Han, Jong-Hoon
    • The korean journal of orthodontics
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    • v.31 no.5 s.88
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    • pp.505-515
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    • 2001
  • The purpose of this study was to measure the average tooth size of Korean with normal occlusion. According to the study, the average tooth ratios between the upper and lower teeth which could assure the proper ovebite, overjet and good interdigitation were calculated. The normal occluson sample of this study consisted of 43 Korean male adults and 51 Korean female adults. Among them, 22 Korean male adults and 51 Korean female adults were from KAO(Korean Association of Orthodontists), 21 Korean male adults were from Department of Orthodontics, College of Dentistry, Yonsei University. The results from this study were as follows : 1 The average tooth size of Korean Norm classified by male and female was measured. 2. The average tooth size of Korean male adults with normal occlusion was significantly larger than that of Korean female adults except upper and lower first molars. (p<0.05) 3. The tooth ratio which could Predict the proper overbite and overjet in anterior teeth and proper occlusion in posterior teeth was calculated. 1) Sum of inciosrs = 4:2.97 2) Neff's anterior coefficient = 1.22 3) Bolton's anterior ratio = 78.29%, overall ratio = 91.14% 4. A positive correlation was observed between the sum of lower anterior incisors and the sum of unilateral canine and premolars In each jaw. Based this correlation, the regression equation was made which could Predict the sum of unerupted unilateral canine and premolars in mired dentition. 1) Sum of unilateral unerupted upper canine and premolars' width = 10.435018 + 0.513346 ${\times}$ (sum or lower 4 incisors' width) 2) Sum of unilateral unerupted lower canine and premolars' width = 9.654002 + 0.502565 ${\times}$ (sum of lower 4 incisors' width)

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