• Imaging Science in Dentistry
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• 제36권1호
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• pp.55-62
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• 2006

Purpose : To find the cause of root curvature by use of panoramic and lateral cephalometric radiograph. Materials and Methods : Twenty six 1st graders whose mandibular 1st molars .just emerged into the mouth were selected. Panoramic and lateral cephalometric radiograph were taken at grade 1 and 6, longitudinally. In cephalometric radio graph, mandibular plane angle, ramus-occlusal plane angle, gonial angle, and gonion-gnathion distance (Go-Gn distance) were measured. In panoramic radio graph, elongated root length and root angle were measured by means of digital subtraction radiography. Occlusal plane-tooth axis angle was measured, too. Pearson correlations were used to evaluate the relationships between root curvature and elongated length and longitudinal variations of all variables. Multiple regression equation using related variables was computed. Results : The Pearson correlation coefficient between curved angle and longitudinal variations of occlusal plane-tooth axis angle and ramus-occlusal plane angle was 0.350 and 0.401, respectively (p<0.05). There was no significant correlation between elongated root length and longitudinal variations of all variables. The resulting regression equation was $Y=10.209+0.208X_1+0.745X_2$ (Y: root angle, $X_1$: variation of occlusal plane-tooth axis angle, $X_2$: variation of ramus-occlusal plane angle). Conclusion : It was suspected that the reasons of root curvature were change of tooth axis caused by contact with 2nd deciduous tooth and amount of mesial and superior movement related to change of occlusal plane.

• 대한치과교정학회지
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• 제21권2호
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• pp.367-397
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• 1991

This study was aimed to investigate the occlusal plane inclination in relation to the skeletal and dental assessment measurements in order to provide a reference in orthodontic treatment planning as the occlusal plane should be reconstructed orthodontically or gnathologically. The sample consisted of 73 normal occlusions and 113 malocclusions of adults. The computerized statistical analysis of 38 occlusal plane's and 29 skeletal and dental measurements were carried out with SPSS. The conclusions were as follows; 1 In normal occlusion, COP-NaPog was average $83.63^{\circ}$ (2.44) and occlusal plane inclination had a strong negative correlation with SNB and FH-NaPog. 2. In normal occlusion, ArANS plane was nearly parallel to the occlusal plane. 3. In malocclusion, the larger the mandibular plane angle and the shorter the ramus height was, the more downward the occlusal plane had a tendency to tip anteriorly. 4. Occlusal plane was more horizontal in deep bite group, while it was steeper in openbite group. 5. The curve of Spee was severe in deep bite group but in openbite group mandibular occlusal plane showed average reverse curvature, where it was found that the configuration of the occlusal plane contributed to the excess or deficiency of anterior overbite.

• The Journal of Advanced Prosthodontics
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• 제9권4호
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• pp.302-307
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• 2017

PURPOSE. This study compared the SCGAs measured in three types of radiographic images (panoramic, CBCT panoramic-section, and CBCT cross-section images) with values measured using the protrusive occlusal record. MATERIALS AND METHODS. SCGAs were measured in 20 patients on a semi-adjustable articulator using the protrusive interocclusal record. Panoramic and CBCT images were obtained. SCGAs were measured on CBCT images in panoramic and cross sections. In all of the radiographic images, SCGAs were measured using the Frankfort horizontal reference line and the mean curvature line. The most-superior and most-inferior points of the curvatures were identified to determine the mean curvature line. Each measurement was performed twice by two operators independently. The data were analyzed by the t-test, Pearson's correlation test, and Cronbach's ${\alpha}$ using SPSS (${\alpha}=.05$). RESULTS. The mean right and left SCGAs were as follows: protrusive occlusal record (30.1 and 30.2 degrees, respectively), panoramic (38.9 and 38.7 degrees), CBCT panoramic sections (35.4 and 36.8 degrees), and CBCT cross sections (35.3 and 36.1 degrees). The SCGAs differed significantly among the groups. The Pearson coefficients for the correlations with the protrusive occlusal record measurements on the left and right sides were as follows: panoramic (0.834 and 0.791, respectively), CBCT panoramic-section (0.918 and 0.837), and CBCT cross-section (0.918 and 0.845) images. CONCLUSION. Strong correlations were found between SCGAs obtained using radiographic images and the protrusive occlusal record.

• 대한치과교정학회지
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• 제24권2호
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• pp.275-294
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• 1994

The occlusal interference during adolescent period makes some effects on growth and development and morphological changes. And so, if we could predict the the timing and results of orthodontic treatment who have occlusal interference during adolescent period, it may be helpful for diagnosis and treatment planning of orthodontic treatment. For about those, the purpose of this study was to evaluate the effects of the posterolateral displacement by the metal casting crown with inclined pathway on the mandibular condyle and morphologic changes of mandible in the rat. The experimental animals were thirty six Sprague-Dawley male rats of 8 weeks old. Eight of them was used as control group, and experimental group 1 ( continuous appliance wearing group ) was composed of sixteen and experimental group 2 ( appliance removal group after worn the appliances during 3 months ) was composed of remaining twelve. The animals of experimental grouop 1 were sacrificed after 1, 2, 3, 6 months from beginning of the experiment and experimental group 2 were sacrificed 1, 2, 3 months after removal of the appliance from worn the appliance during 3 months. Both of mandible and temporomandibular joint were observed histologically and radiologically. The results were as follows : 1. In experimental group 1, the mandibular length and lower posterior height were decreased with experimental period, while the lower anterior height was increased, and the curvature of lower incisors and lingual inclination of anterior alveolar bone were profound as compared with control group. 2. In experimental group 1, both of the thickness of the condylar cartilage were thinned in the posterosuperior region, and this phenomenon was more prominent on right than left in 3-Mo experimental period and both sides were marked thinned in 6-Mo experimental period. 3. In experimental group 2, the lower anterior height was low and lower posterior height was high as compared with experimental group 1, and the curvature of lower incisors and lingual inclination of anterior alveolar bone were recovered to control group. 4. In experimental group 2, both of the thickness of the condylar cartilage were thickened in the posterosuperior region, and this phenomenon was more prominent with experimental period. 5. In experimental group 2, the mandibular length was short, lower anterior height was hight, the curvature of lower incisors were profound, and in histologically, both of the thickness of the condylar cartilage were thickened in the posterosuperior region as compared with control group. As shown above, the occlusal interfemce affected the condylar cartilage, curvature of lower incisor, inclination of anterior alveolar bone, mandibular length, and anterior and posterior height. When the interference was removed, significant recover was found in condylar cartilage, mandibular length, and posterior height. Although no significance was found, other items of measurement showed trends for recovery.

• 대한치과보철학회지
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• 제36권2호
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• pp.323-335
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• 1998

Clinically, the curve of Spee is widely applied as a determined level of the occlusal curvature when the oral rehabilitation and the reconstruction of the prosthesis is needed at the malalignment dentition due to the missing, extrusion, and the inclination of the teeth. The purpose of this study was to analyze the curve of Spee of the occlusal curvature which influences to the occlusal form and the location three dimensionally, and then was to measure the radius and the degree of curvature of the curve of Spee and also was to investigate the influence to the cuspal inclination according to the change of the inclination of the curve of Spee which was analyzed by AutoCAD R.13 program at the gnathological cast and the cephalometric radiograph. The following results were obtained : 1. The radius of the curve of Spee was the mean of $11.74{\pm}3.64cm$ in the model, $12.75{\pm}4.63cm$ in the radiograph and there was no significant difference statistically between the model and the radiograph(P>0.001). 2. The radius and the degree of curvature of the curve of Spee showed negative correlation(r=-0.80), while the radius and the degree of curvature of the curve of Spee in relation to the length of the curve of Spee did not show correlation. 3. The case of the curve of Spee inclined to the posterior, that is. $Post.M{\theta}$ group showed the mean of $4.73{\pm}3.64$, positive correlation to the P2m, M1mm, M1dm, M2dm, and especially the greatest correlation coefficient to the mesial inclination angle of the mesio-buccal cusp tip of the first molar(r=0.70). 4. The case of the curve of Spee inclined to the anterior, that is, $Ant.M{\theta}$ group showed the mean of $3.28{\pm}3.59$, positive correlation to the P2m, M1mm, and also the greatest correlation coefficient to the mesial inclination angle of the mesio-buccal cusp tip of the first molar(r=0.78

• 대한치과기공학회지
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• 제38권3호
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• pp.217-224
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• 2016

Purpose: This study aimed to generate 3-D occlusal curvatures and evaluate the relationship between the occlusal curvatures and mandibular occlusal morphology factors. Methods: Mandibular dental casts from 25 young adult Korean were scanned as a virtual dental models with a 3-D scanner(Scanner S600, Zirkonzahn, Italy). The curve of Spee, curve of Wilson, and Monson's sphere were generated by fitting a circle/sphere to the cusp tips using a least-squares method. The mandibular mesiodistal cusp inclination, buccolingual cusp inclination, and tooth wear parameters were measured on the prepared virtual models using RapidForm2004(INUS technology INC, Seoul, Korea). Wilcoxon signed-rank test was performed to test side difference, and Spearman's rank correlation coefficients were investigated to verify the correlation between occlusal curvatures and correlated factors (a=0.05). Results: The mean radii of curve of Spee were $83.09{\pm}33.94$ in the left side and $79.00{\pm}28.12mm$ in the right side. The mean radii of curve of Wilson were $66.82{\pm}15.87mm$ in the mesial side and $47.87{\pm}9.40mm$ in the distal side with significantly difference between mesiodistal sides(p<0.001). The mean radius of Monson's sphere was $121.85{\pm}47.11mm$. Most of the cusp inclination parameters showed negative correlation for the radius of Monson' sphere(p<0.05). Especially, the buccolingual cusp inclinations in mesial side of molar showed high correlation coefficients among the factors(p<0.05). Conclusion: The radius of Monson's sphere was greater than the classical 4-inch values, and the buccolingual cusp inclinations in mesial side of molar can be considered as one of the main factors correlating with the radius of Monson's sphere.

• 치과방사선
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• 제13권1호
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• pp.117-126
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• 1983

The mandibular canal must be considered carefully during surgical treatment, especially surgical extraction of the impacted tooth and intraosseous implant because it contains the important inferior alveolar nerve and vessels. The author investigated the curvatUre of the mandibular canal, the positional frequency of mandibular foramen to the occlusal plane and gonial angle and the positional frequency of the mental foramen to the tooth site using orthopantomograms. The materials consisted of 295 orthopantomograms divided into seven groups ranging from the first decade to 6th. decade. The results were as follows: 1. The position of mandibular foramen was most frequently below occlusal plane in Group Ⅰ (78.6%) and Group Ⅱ (71.2%), above occlusal plane in Group Ⅲ (63.0%), Group IV (71.1%), Group V (57.6%), Group (76.7%) and Group VII (70.0%). 2. The curvature of mandibular canal was 142.8° in Group Ⅰ, 142.09° in Group Ⅱ, 139.34° in Group Ⅲ, 141.48° in Group Ⅳ, 138.45° in Group Ⅴ, 140.77° in Group Ⅵ and 143.89° in Group Ⅶ. 3. The gonial angie was 125.82° in Group Ⅰ, 123.18° in Group Ⅱ, 124.06° in Group Ⅲ, 120.45° in Group Ⅳ, 121.12° in Group Ⅴ, 121.63° in Group Ⅵ and 121.24° in Group Ⅶ. 4. The position of the menta] foramen was most frequently below the apex of mandibular first premolar in Group Ⅰ (57.2%), between the apex of mandibular first and second premolar in Group Ⅱ (59.6%) and Group Ⅲ (48.9%), and below the apex of mandibular second premolar in Group Ⅳ (39.2%), Group Ⅴ (48.5%) Group Ⅵ(46.6%) and Group Ⅶ(56.4%)

• 대한치과교정학회지
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• 제38권2호
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• pp.95-103
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• 2008

본 연구는 한국인의 치아형태에 적합한 브라켓 베이스를 만들기 위해 임상 치관의 순,협측 곡률을 3차원적으로 계측하여 치관의 곡률 자료를 얻고자 하였다. 정상적인 해부학적 형태를 가지는 구강모형 30쌍을 3차원 디지털 모델로 제작한 후, FA점을 기준으로 수평 기준면과 수직 기준면을 설정하였다. 이 기준면에 대한 치면의 곡선을 형성한 후, 곡률을 이차방정식의 계수로 표현하였다. 수평면과 수직면의 곡률과 FA점을 기준으로 근심과 원심, 치은측과 교합면측의 곡률을 측정한 결과, 상악견치와 상악 제2소구치 외에는 남녀간 치면 곡률의 유의한 차이가 없었다. 하악 측절치, 상악 견치, 상하악 제1, 2소구치와 제1대구치에서 근원심 또는 치은교합면측 치면 곡률의 유의한 차이가 관찰되었다 (p < 0.05). 본 연구에서 얻어진 순,협측 치면의 곡률 자료는 한국인의 치아 형태에 적합한 Straight Wire Appliance 개발의 기초 자료로 활용될 수 있다.

• Journal of Oral Medicine and Pain
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• 제20권2호
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• pp.361-376
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• 1995

The purpose of this study was to investigate the relationship between the head and neck postre and the cervical curvature, especially in forward head postrue(FHP). Sixty patients with craniomandibular disorders and thirty dental students without any signs and symptoms of craniomandibular disordres participated in this study as patient groups and sa control group, respectively. The author evaluated the head and neck posture of all subjects by plumb line and CROM( Cervical Ragne of Motion), and had taken cephaograph in natural head position. On the cephalograph the angle of cervical inclination formed by true horizntal plane and 4th cervical vertebra(C4) and the radius of cervical curvature from C1 to C5 were measured. A specially designed ruler was used for measuring cervical curvature. Occlusal contac number and force with T-scan system, electromygraphic activity of cervical muscles with Bio-EMG, and distance of freeway space with Bio-ECN were recorded, respectively. The collected data were processed by SAS/STAT progrm. The obtained results were as follows : 1. In subjects with longer radius which was less cervical curvature, head positioned more anteriorly than subjects with smaller radius, and they showed slightly straight cervical vertebra. 2. Between the patients and the control group, there were no differences in cervical curvature, in forward head position by plumb line and in CROM. But the patient group had a greater cervical inclination than the control group had. 3. There were positive correlation between cervical curvature and forward head position by plumbline,between forward head position y plumb line and that by CROM in patient group. The cervical inclination, however, had negative correlation with cervical curvature, and with forward head postion by plumb line, respectively. 4. In case of showing more cervical curvature and more forward head position by plumb line the head position was defined as forward head posture. In patient group, subjects without forward head posture showed greater posterior teeth contact force than subjects with forward head posture, but in control group, there were no difference between the two subjects. 5. There were higher electromyographic activity in almost all muscles and smaller freeway space in induced forward head posture than those in natural head position in subjects without forward head posture. In conclusion, head position of patients with craniomandibular disorders were not more anterior than that of normal control person, but they had tendency to head extension. From the result of this study, forward head posture could be defined as posterior rotation of upper cervical segment with a straight lower cercial segment due to loss of normal lordosis.

• 구강회복응용과학지
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• 제30권2호
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• pp.93-101
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• 2014

목적: 본 연구의 목적은 한국인에서 스피만곡의 전형적인 형태와 성별, 연령, 좌우측에 따른 스피만곡을 분석하는 것이다. 연구 재료 및 방법: 콘빔형 단층촬영을 한 원광대학교 치과대학 산본치과병원 환자 중에서 본 연구의 기준에 합당한 500명(남자: 311, 여자: 189)의 이미지를 선정하였고, 스피만곡을 시상면 상에서 분석하였다. 결과: 한국에서 스피만곡 평균 반경은 91.4 mm였다. 스피만곡 반경의 성별에 의한 통계학적 유의성은 있었으나, 연령과 좌우간의 유의성은 보이지 않았다. 결론: 본 연구의 제한적 상황 내에서 몬슨에 의해서 주창되었던 101.6 mm보다 더 적은 한국인의 스피만곡의 반경은 특히 한국인에서 교합평면을 재건할 경우 모든 경우에서 스피만곡 수치를 그대로 적용하는 것을 재고해 볼 필요성을 제기한다.