• 대한치과교정학회지
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• 제16권2호
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• pp.123-133
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• 1986

The purpose of this study was to collect the information of the straight-wire appliance and to determine the amount of second-order bends in clinical orthodontics. The author analysed the study model of 50 individuals with normal occlusion and results were obtained as follows. 1. The crown angulation was 4 degree in upper central incisor, 7 degree in upper lateral incisor, and 0 degree in lower central incisor and lateral incisor. 2. The crown angulation was 8 degree in upper cuspid and 2 degree in lower cuspid. 3. The crown angulations were 4 degree in upper first bicuspid, upper second bicuspid and lower second bicuspid and 1 degree in lower first bicuspid. 4. The crown angulation was 3 degree in upper first molar, 0 degree in upper second molar, 5 degree in lower first molar and 8 degree in lower second molar. 5. The crown angulations in lower arch were progressively increased from first premolar to second molar. 6. In upper arch, as the crown angulation of one tooth was increased, those of adjacent teeth were increased, too. 7. In the case of lower arch, the crown angulation of cuspid was increased as that of lateral incisor was increased, the crown angulation of second premolar was increased as that of first premolar was increased, and similarity the crown angulation of second molar was increased as that of first molar was increased.

• 대한치과기공학회지
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• 제35권4호
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• pp.415-424
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• 2013

Purpose: This study is to present a standard value for clinical crown angulation and inclination required in laboratory process and see if the value can be used for actual laboratory process. Methods: In order to find out a standard value for clinical crown angulation and inclination, this study made a study model of normal occlusion of 21 females in twenties. The clinical crown angulation and inclination of both six-maxillary and six-mandibular anterior teeth are measured by Set-up Model Checker. From the measured value above, the mean and standard deviation of the twelve teeth are obtained, and then the mean of the teeth between right and left side is calculated. Results: Each clinical crown angulation of maxillary central incisor, lateral incisor, and canine is like this; $1.0^{\circ}{\pm}1.3^{\circ}$, $3.0^{\circ}{\pm}1.3^{\circ}$, and $5.0^{\circ}{\pm}1.4^{\circ}$. In case of mandibular, each degree is like this; $0.6^{\circ}{\pm}1.1^{\circ}$, $1.5^{\circ}{\pm}1.1^{\circ}$, and $4.1^{\circ}{\pm}1.1^{\circ}$. Each clinical crown inclination of maxillary central incisor, lateral incisor, and canine is like this; $6.1^{\circ}{\pm}1.8^{\circ}$, $4.5^{\circ}{\pm}1.9^{\circ}$, and $-6.2^{\circ}{\pm}1.4^{\circ}$. In case of mandibular, each degree is like this; $0.3^{\circ}{\pm}1.5^{\circ}$, $0.3^{\circ}{\pm}1.8^{\circ}$, and $-7.5^{\circ}{\pm}1.8^{\circ}$. Conclusion: As the result, the mean value for clinical crown angulation and inclination can be referred to actual laboratory process. However, the mean value is different from those of the precedent study and an unsatisfied one for adopting the standard value.

• 대한치과교정학회지
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• 제28권4호
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• pp.601-609
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• 1998

한국인에 적합한 preadjusted bracket을 개발하기 위하여 한국인 성인 정상 교합자 14명을 대상으로 crown angulation, inclination, in and out, molar offset angle을 구했다. 정상 교합자 14명의 cast를 3차원 스케닝한 후 스케닝한 모델을 대상으로 컴퓨터 프로그램을 이용하여 측정하였다. 이는 기존의 모델을 직접 수작업으로 측정할 때보다 정확하고 빨리 측정할 수 있었다. 다음과 같은 결론을 얻었다. 1. 한국인 정상교합자의 각 치아의 치축 경사(angulation), 치관 경사도(inclination), in and out, molar offset angle을 구하였다. 2. 3차원 스케너와 컴퓨터를 이용하여 측정하였기 때문에 보다 정확하고, 빠르게 측정할 수 있었다.

• 구강회복응용과학지
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• 제20권2호
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• pp.135-141
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• 2004

Statement of problem: Arrangement and angulation of clinical crown is very important for esthetic restoration in the upper anterior dentition. However, there was no clinical criteria to mesial angulation of the crown for Korean. Purpose: This study was undertaken to estimate the mesial angulation of the crown of the anterior teeth and the Oh's E-triangle made of the inter-pupillary line and the mesial inclination lines of the canines. Material and Method: 270 portraits of Korean were used for this study. The mesial angulation of the upper anterior teeth and the relationship of the inter-pupillary line and the mesial inclination lines of the canines were measured with the tools of PhotoShop software on the scanned images. Results: The angulation between the clinical crowns having a same name in the upper anterior dentition were $3.6^{\circ}$ between the central incisors, $8.6^{\circ}$ between the lateral incisors, and $13.6^{\circ}$ between the canines. There was no significance according to occupation and gender( P > 0.05). The ratio of height to base line of Oh's E-triangle was 4.47. 81.6% of the subjects showed the mesial inclination line of the canine passed by mesial border area of pupil. Conclusion: These data for Korean would be useful clinically to give the esthetic arrangement and to make the contour of upper anterior teeth.

• 대한치과교정학회지
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• 제28권5호
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• pp.731-740
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• 1998

이전의 preadjusted appliance 개발을 위한 치관경사도의 계측에 있어서는 교합평면을 계측기준으로 사용했는데, 교합평면은 Spee 만곡으로 인해 브라켓 부착점들을 연결하는 선(Andrews' plane)에 평행하지 않은 문제점이 있었다. 따라서 본 연구에서는 Spee 만곡에 영향받지 않으며, Andrews' plane에 보다 평행한 계측기준으로 각각의 구치의 근, 원심측 변연융선을 잇는 가상선을 설정하고, 이를 변연융선평면으로 명명하였다. 교합평면과 변연융선평면으로부터 각각 정상교합자의 구치부 치관경사도를 계측하여 비교한 결과 교합평면을 기준으로 한 치관경사도가 특히 상, 하악 제 1소구치(P<0.05) 및 제 2대구치(P<0.01)에서 Spee 만곡의 영향을 받음을 발견하였다. 구치부 치아들의 치관경사도는 Spee 만곡의 양에 따라 변해야만 인접치간 변연융선의 불일치가 생기지 않는다. 이전의 연구들에서는 다소의 Spee만곡을 갖는 정상교합자 표본에서 교합평면을 기준으로 계측한 치관경사도를 Spee 만곡이 없는 교합평면이 치료 목표의 일부인 bracket system에 적용하는 오류가 있었다. 이러한 치관경사도와 Spee 만곡 사이의 부조화는 Spee만곡이 straight wire에 의해 완전히 leveling되었을 때 변연융선 불일치를 초래할 수 있다. 이를 해결하기 위해서는 구치부 브라켓 slot이 변연융선평면에 평행하도록 브라켓 경사도를 결정하는 것이 추천된다.

• 대한치과교정학회지
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• 제35권5호
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• pp.331-340
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• 2005

치관경사도 연구는 부정교합 진단과 치료 계획 수립 및 더욱 편리한 교정 장치 개발과 관련한 기초 자료로써 중요시되어 왔다 이에 본 연구는 307명(남자 187명, 여자 120명)의 대표본 성인 정상교합자를 연구대상으로 삼아 자료의 신뢰성 검증이 병행된 치관경사도를 보고함으로써 치과교정학 임상에 도움이 되는 기초자료를 도출해 보고자 시행되었다. 치관경사도 측정을 위하여 정상교합자 표본의 모형 상에서 개개 치아의 근원심 각도 및 협설측 각도를 측정하였으며, 측정 전후 측정자간 및 측정자 내의 신뢰성 검증을 시행하였고. 남녀간의 성차와 기존 연구자료와의 차이를 검증하였다. 연구 결과 본 연구가 대표본을 대상으로 하여 높은 신뢰성 지표를 보였음에도 불구하고 정상교합자의 치관경사도는 변동이 심한 것이 관찰되었고 이에 따라 기존 연구들에 대비하여 임상적으로 유의한 자료상의 차별성은 고찰할 수 없었으며 변동의 양상 또한 선학들이 보고한 자료와 유사하였다 결론적으로 치관경사도 측정시 드러난 정상변동을 해석하여 개별 적합성이 최대로 증진된 효율적인 치과교정장치를 개발하기 위해 좀 더 발전된 수학적·통계학적 모형 구성이 필요할 것으로 생각되었다

• 대한치과교정학회지
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• 제38권4호
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• pp.265-274
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• 2008

3D CT를 이용하여 파노라마에서 얻어진 상악 매복 견치 위치 정보의 유용성을 평가하기 위해, 상악 견치 매복을 주소로 경북대학교병원에 내원한 환자를 대상으로 파노라마 방사선 사진과 3D CT에서의 매복 견치의 위치를 평가하였다. 대상은 25명(남자 7명, 여자 18명)으로 평균 나이는 10.9세(범위 : 8.2 - 15.7세)이며, 35개의 상악 매복 견치증례를 분석하여 다음의 결과를 얻었다. 첫째, 파노라마 방사선 사진은 확대되어 촬영되므로 3D CT의 계측치보다 상악 견치의 tooth length, crown width, vertical distance 그리고 lateral shift값에서 큰 값을 가졌다. 단, angulation to occlusal plane은 파노라마에서 더 작은 값으로 계측되었다. 둘째, 파노라마 방사선 사진상 상악 견치가 구개측으로 매복된 경우, angulation to occlusal plane은 3D CT보다 작게 측정되고 vertical distance는 더 크게 측정되었다. 셋째, 파노라마 방사선 사진에서 상악 매복 견치의 tooth length, crown width 그리고 순측으로 매복된 경우 상악 견치의 angulation to occlusal plane은 3D CT와 근접된 계측치를 가졌다. 또한 CT와 비교하였을 때, 치근 흡수 정도 평가에 대한 파노라마 방사선 사진의 감수성은 33.3%인 것으로 측정되었다. 파노라마 방사선 사진은 협측 매복견치의 위치는 실제와 유사하다고 생각되나 구개측 매복의 경우 3D CT보다 더 높게, 각도는 더 작게 나타나는 등 상당한 차이가 있어 CT를 이용한 추가적인 검사가 필요하다고 생각된다.

• 대한치과교정학회지
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• 제50권4호
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• pp.229-237
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• 2020

Objective: To evaluate the construction reproducibility of a composite tooth model (CTM) composed of an intraoral-scanned crown and a cone-beam computed tomography (CBCT)-scanned root. Methods: The study assessed 240 teeth (30 central incisors, 30 canines, 30 second premolars, and 30 first molars in the maxillary and mandibular arches) from 15 young adult patients whose pre-treatment intraoral scan and CBCT were available. Examiner-Reference (3 years' experience in CTM construction) and Examiners-A and Examiner-B (no experience) constructed the individual CTMs independently by performing the following steps: image acquisition and processing into a three-dimensional model, integration of intraoral-scanned crowns and CBCT-scanned teeth, and replacement of the CBCT-scanned crown with the intraoral-scanned crown. The tooth axis angle in terms of mesiodistal angulation and buccolingual inclination of the CTMs constructed by the three examiners were measured. To assess the construction reproducibility of CTMs, intraclass correlation coefficient (ICC) assessments were performed. Results: The ICC values of mesiodistal angulation and buccolingual inclination among the 3 examiners showed excellent agreement (0.950-0.992 and 0.965-0.993; 0.976-0.994 and 0.973-0.995 in the maxillary and mandibular arches, respectively). Conclusions: The CTM showed excellent construction reproducibility in mesiodistal angulation and buccolingual inclination regardless of the construction skill and experience levels of the examiners.

• 대한치과교정학회지
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• 제52권6호
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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.

• Journal of Oral Medicine and Pain
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• 제13권1호
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• pp.13-21
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• 1988

The author studied the vertical height of tooth crown and the amounts of alveolar bone resorption with age. All 84 subjects(44 male, 40female) who visited Dental hospital of Wonkwang University with no history of sever periodontal disease and no experience of periodontal surgery. 84 subject were divided into 3 groups by age, that is, group I(28-32yrs), group II(38-42yrs), and group III(48-52yrs). Informal radiogram with bite wing film(horizontal angulation : $0^{\circ}$, vertical angulation : $+5^{\circ}~+10^{\circ}$) were taken on premolar and molar area. The distances from cusp tip to cementoenamel junction (vertical height of tooth crown) and from cementoenamel junction alveolar crest(amount of alveolar bone resorption) were measured, and then recorded data from 946 teeth were statistically analysed. This study was undertaken to obtain the data for age estimation by the changes of tooth crown height and alveolar bone resorption in the point of forensic odontology. The obtained results were as follows : 1. The average crown height of mandibular right 1st. molar was 7.1mm in group I, 6.7mm in group II, and 6.6mm group III, and the average amount of alveolar bone resorption on mandibular right 1st. molar were 1.8mm in group I, 2.5mm in group II, and 3.0mm in group III. Ratio of tooth crown height to amount of alveolar bone resorption was 4.0:1 in groupI, 2.7:1 in group II, and 2.2:1 in group III, the ratio was decreased with age. 2. In comparison with upper teeth and lower teeth in ipsilateral side, the average value of tooth crown height and amount of alveolar bone resorption were slightly higher in upper arch than those in lower arch, but there was not a statistically significant difference. 3. The ratio of height of tooth crown to amount of alveolar bone resorption was decreased with age, and which depended mainly upon the change of amount of alveolar bone resorption rather than the change of tooth crown height.