• Imaging Science in Dentistry
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• 제48권3호
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• pp.191-199
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• 2018

Purpose: This study classified alveolar arch forms and evaluated differences in alveolar bone thickness among arch forms in the anterior esthetic region using cone-beam computed tomography (CBCT) images. Materials and Methods: Axial views of 113 CBCT images were assessed at the level of 3 mm below the cementoenamel junction (CEJ) of the right and left canines. The root center points of teeth in the anterior esthetic region were used as reference points. Arch forms were classified according to their transverse dimensions and the intercanine width-to-depth ratio. The buccolingual alveolar bone thickness of each tooth was measured at 3 mm below the CEJ and at the mid-root level. Differences in the mean thicknesses among arch forms were analyzed. Results: Anterior maxillary arches could be classified as long narrow, short medium, long medium, and long wide arches. Significant differences in buccolingual alveolar bone thickness among the arch groups were found at both levels. The long wide arches presented the greatest bone thickness, followed by the long medium arches, while the long narrow and short medium arches were the thinnest. Conclusion: Arch forms were classified as long narrow, short medium, long medium, and long wide. The buccolingual alveolar bone thickness exhibited significant differences among the arch forms.

• 대한치과교정학회지
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• 제42권1호
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• pp.47-54
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• 2012

Objective: To determine and compare the frequency distribution of various arch shapes in ethnic Malays and Malaysian Aborigines in Peninsular Malaysia and to investigate the morphological differences of arch form between these two ethnic groups. Methods: We examined 120 ethnic Malay study models (60 maxillary, 60 mandibular) and 129 Malaysian Aboriginal study models (66 maxillary, 63 mandibular). We marked 18 buccal tips and incisor line angles on each model, and digitized them using 2-dimensional coordinate system. Dental arches were classified as square, ovoid, or tapered by printing the scanned images and superimposing Orthoform arch templates on them. Results: The most common maxillary arch shape in both ethnic groups was ovoid, as was the most common mandibular arch shape among ethnic Malay females. The rarest arch shape was square. Chi-square tests, indicated that only the distribution of the mandibular arch shape was significantly different between groups (p = 0.040). However, when compared using independent t-tests, there was no difference in the mean value of arch width between groups. Arch shape distribution was not different between genders of either ethnic group, except for the mandibular arch of ethnic Malays. Conclusions: Ethnic Malays and Malaysian Aborigines have similar dental arch dimensions and shapes.

• 대한치과교정학회지
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• 제49권2호
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• pp.89-96
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• 2019

Objective: The purpose of this study was to assess the long-term stability of rapid palatal expansion (RPE) followed by full fixed edgewise appliances. Methods: This study included 67 patients treated using Haas-type RPE and non-extraction edgewise appliance therapy at a single orthodontic practice. Serial dental casts were obtained at three different time points: pretreatment ($T_1$), after expansion and fixed appliance therapy ($T_2$), and at long-term recall ($T_3$). The mean duration of the $T_1-T_2$ and $T_2-T_3$ periods was $4.8{\pm}3.5years$ and $11.0{\pm}5.4years$, respectively. The dental casts were digitized, and the computed measurements were compared with untreated reference data. Results: The majority of treatment-related increases in the maxillary and mandibular arch measurements were statistically significant (p < 0.05) and greater than expected for the untreated controls. Although many measurements decreased postretention ($T_2-T_3$), the net gains persisted for all of the measurements evaluated. Conclusions: The use of RPE therapy followed by full fixed edgewise appliances is an effective method for increasing maxillary and mandibular arch width dimensions in growing patients.

• 대한치과교정학회지
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• 제27권3호
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• pp.457-471
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• 1997

본 연구는 치열궁 길이 부조화(Arch length discrepancy : 이하 ALD)의 원인요소간의 상대적 중요성과 혼합치열기에서의 예측가능성을 알아보고자 시행되었다. Angle씨 I급 대구치관계이며 근기능 이상이나 골격형태의 이상이 없다고 판단되는 142명의 진단모형을 이용하여 성별과 ALD의 양에 따라 여섯군으로 나누어 각 치아의 크기와 치열궁 각 부위의 크기를 계측하였다. SPSS통계처리 프로그램을 이용하여 각군의 평균, 표준편차를 구하고 Student t-test, 상관관계 분석, 요인분석, 다중회귀분석을 실시하였으며 혼합치열기에서 얻을 수 있는 자료들을 이용한 ALD의 예측가능성을 평가하여 다음과 같은 결과를 얻었다. 1. 성별에 따른 차이는 정상군에서는 거의 보이지 않았으며 spacing군은 대부분의 계측치에서, crowding군은 몇가지 치열궁의 크기에 관한 계측치에서 유의한 차이를 보였다. 2. 남자crowding군과 여자 spacing군은 해당 정상군에 비해 주로 치아크기에 관한 계측치에서 유의한 차이를 보였다. 3. 남자 spacing군과 여자crowding군은 해당 정상군에 비해 치열궁의 크기에 관한 계측치에서 유의한 차이를 보였다. 4. 상관관계분석과 요인분석결과에서는 주로 치열궁의 크기에 관한 계측치들이 ALD와 큰 연관성을 나타내었다. 5. 혼합치열기에서 얻을 수 있는 정보인 중절치, 측절치, 제1대구치의 폭경과 제1대구치간 폭경, 치열궁 장경 을 이용한 ALD의 다중회귀분석은 최소 $63\%$에서 최대 $80\%$의 예측도(R square)를 보였다.

• 대한치과교정학회지
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• 제24권4호
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• pp.773-785
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• 1994

It has been generally believed that the impaction or eruption of mandibular third molars has significant correlations with the growth of the mandible, size of mandibular arch and size of teeth. The purpose of this study was to examine if there is any correlation between the status of eruption of mandibular third molars and the amount of mandibular crowding. The effect of missing of third moalrs to mandibular crowding was studied as well. 140 adult students of Yonsei University were selected and divided into three groups according to the status of mandibular third molars, Group 1) congenital missing group, Group 2) eruption group, and Group 3) impaction group. The tooth size, dimensions of the mandibular dental arch, and the amount of crowding were measured and compared. Results were as follows ; 1. There was no statistically significant difference in tooth size between the missing group and the eruption group(p<0.05). Impaction group showed larger total tooth material, inci- sal tooth material, and individual tooth size except central incisors compared to missing group (p<0.05). Impaction group showed larger total tooth material, incisal tooth material compared to eruption group as well(p<0.05). When individual tooth size was compared, impaction group had larger central incisors, canines, and second premolars than eruption group(p<0.05). 2. Missing group showed larger intermolar width than impaction group and it was stati- stically significant(p<0.05). 3. When compared the amount of total crowding, impaction group showed the largest am- ount of crowding, then eruption group, and missing group showed the least amount of crowding respectively(p<0.05). There was no statistically significant difference between missing stoup and eruption group in the amount of incisal crowding(p<0.05). Impaction group show- ed the largest amount of incisal crowding among all three groups(p<0.05).

• 대한치과교정학회지
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• 제14권1호
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• pp.93-101
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• 1984

Human dental arches are very various in their sizes and dimensions as well as forms, so, it is very difficult to describe the shape of human dental arches as a criterion, and, further, to construct the preformed arch wires fit to them. In this study for solving these problems, the shape of eighty Korean normal lower dental arches were studied, and nine theoretical two-parameter catenary curves were derived, which were representative of all of the sample. Test were conducted which demonstrated that these nine cattenary curves would correspond with a reasonable degree of accuracy to all of the dental arches, lower and upper.

• 대한치과교정학회지
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• 제36권1호
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• pp.84-90
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• 2006

이 연구의 목적은 강화지역의 한국인 아동의 유치열기에서의 공극과 총생의 빈도를 조사하고, 치아 크기와 치열궁간의 관계를 조사하는 것이다. 102개의 취학전 아동(남자 57명, 여자 45명, $4{\sim}5$세)의 석고모형을 조사하여 치아의 크기, 견치간 폭경, 구치부 폭영, 치열궁 장경을 측정하였다. 유치열기의 공극 빈도는 남자에서 63.2%, 여자에서 57.8%로 나타났다. 공극의 빈도는 남자에서, 하악보다는 상악에서 더 높게 나타났다. 공극이 있는 경우보다 총생을 보이는 치열에서 치아 크기는 크고 치열궁 폭경은 더 작게 나타났다 (p<0.05). 전치부 공극의 존재 여부는 치아의 크기, 견치간 폭경과 관련이 있었다.

• Journal of Korean Dental Science
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• 제2권2호
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• pp.18-23
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• 2009

Introduction : The purposes of this study were to analyze the differences between the anterior and posterior overjets using bracket slot points, and compare two methods of overjet calculation according to different reference points using clinical bracket points on three-dimensional digital models. Methods : A total of 35 normal occlusion models were scanned using a three-dimensional scanner (Orapix$^{(R)}$, Orapix Co., Ltd, Seoul, Korea) and then, virtual brackets (0.022" Slot MBT preadjusted brackets, 3 M Co.CA. USA) were placed on the digital models using virtual setup program (3Txer$^{(R)}$ ver. 1.9.6, Orapix co., Ltd). Archwire-like curves were designed to analyze labial and buccal overjet. Results : There were no statistically significance differences between the right and left overjet and between genders. The average overjet was found to be $1.67{\pm}0.85mm$ at the central incisor area, $2.16{\pm}0.88mm$ at the second premolar and $1.53{\pm}0.71mm$ at the first molar. Conclusion : It is recommended that overjet of individualized upper and lower arch to be 2.0mm at the anterior and posterior teeth.

• 대한치과교정학회지
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• 제37권5호
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• pp.364-375
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• 2007

본 연구의 목적은 한국인과 일본인의 Angle씨 I급, II급, III급 부정교합군에서 하악치열궁의 크기와 형태적 특성을 상호 비교 분석하는데 있었다. 한국인의 부정교합자 368명(I급 114명, II급 119명, III급 135명)과 일본인의 부정교합자 160명(I급 60명, II급 50명, III급 50명)을 대상으로 하였다. 치료 전 하악 치열 모형을 복사한 사진에서 13개의 인접한 접촉면에서 가장 협측에 위치한 점들을 좌표치화한 후 하악 치아의 두께 자료에 근거하여 임상 브라켓 점들을 설정하였고 4개의 선 계측과 이들을 이용하여 2개의 비율을 측정하였다. 각 부정교합군에서 측정 항목들에 관하여 t-test를 하였고 치열궁 형태를 square, ovoid, tapered 의 3가지로 분류한 후 분포 특성에 관하여 카이제곱 검정하였다. 그 결과 I급과 II급 부정교합군에서 일본 여성의 하악 치열궁 폭경이 일본남성, 한국 남성 및 한국 여성에 비해 작았으며, III급 부정교합군의 하악 치열궁 크기는 인종이나 성별에 따른 차이가 없었다. 그리고 모든 부정교합군에서 한국인과 일본인의 대부분이 square와 ovoid한 치열궁 형태를 가졌으며 II급 부정교합군에서는 일본인은 ovoid 형태가 52.%으로 가장 많고 한국인은 square 형태가 40%로 가장 많게 나타났다.

• 대한치과교정학회지
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• 제34권6호
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• pp.481-487
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• 2004

본 연구의 목적은 한국인 정상교합자에서 하악치열궁의 형태적 차이를 알아보고자 하였다. 한국인 102명의 정상교합자를 대상으로 하악 모형의 교합면을 복사한 후 13개의 접촉점중에서 가장 협측으로 위치한 부분을 digitize하였고 각 치아의 브라켓위치에 해당하는점을 하악치아의 두께에 의거하여 4개의 선계측과 2개의 비율을 측정하였다. 치열궁의 형태를 square, ovoid, tapered from으로 분류하여 그 빈도를 남녀성별에 따라 비교한 결과 특이한 차이점을 보이 지 않았으나 대구치간 폭경에서는 남녀 성별의 차이를 보였다. 정상교합자에서 치열궁 형태분포는 ovoid, square, tapered순 이었고 tapered arch from은 $10\%$미만이었다. 치열궁 형태의 빈도분포에 있어서 남녀간의 차이는 없었다.