• 대한소아치과학회지
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• 제48권3호
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• pp.245-254
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• 2021

이 연구의 목적은 소아 환자들의 측모방사선 사진을 대상으로 시판되는 3종의 자동 계측점 식별 프로그램의 정확성을 평가하고 소아치과 임상에서의 사용 가능성을 예측하는 것이다. 영구 중절치가 맹출한 만 7 - 12세 건강한 어린이 60명의 측모방사선 사진에 14개의 계측점을 표시하였다. 1명의 검사자가 3회 반복 측정한 결과의 평균을 기준점으로 정의하여 자동으로 식별된 계측점과의 거리 차이를 계측하였다. 3종의 자동 계측점 식별 프로그램은 평균 2.53 mm의 오차를 나타냈다. Orbitale과 Gonion을 제외한 12개의 계측점에서 3종의 프로그램 사이에 유의미한 차이는 없었으나, 검사자가 모든 계측점에서 3종의 프로그램보다 유의미하게 높은 정확도를 보였다. 이 연구를 통하여 사춘기 전 소아의 측모방사선 분석 시 자동 계측점 식별 프로그램이 검사자를 대체할 정도는 아니나 짧은 소요시간과 임상 허용 가능한 범위 이내의 정확도를 갖는 효과적인 진단 보조기구임을 알 수 있다.

• Imaging Science in Dentistry
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• 제47권1호
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• pp.1-9
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• 2017

Purpose: This retrospective study aimed to evaluate the nasopharyngeal and oropharyngeal dimensions of individuals with skeletal class II, division 1 and division 2 patterns during the pre-peak, peak, and post-peak growth periods for comparison with a skeletal class I control group. Materials and Methods: Totally 124 lateral cephalograms (47 for skeletal class I; 45 for skeletal class II, division 1; and 32 for skeletal class II, division 2) in pre-peak, peak, and post-peak growth periods were selected from the department archives. Thirteen landmarks, 4 angular and 4 linear measurements, and 4 proportional calculations were obtained. The ANOVA and Duncan test were applied to compare the differences among the study groups during the growth periods. Results: Statistically significant differences were found between the skeletal class II, division 2 group and other groups for the gonion-gnathion/sella-nasion angle. The sella-nasion-B-point angle was different among the groups, while the A-point-nasion-B-point angle was significantly different for all 3 groups. The nasopharyngeal airway space showed a statistically significant difference among the groups throughout the growth periods. The interaction among the growth periods and study groups was statistically significant regarding the upper oropharyngeal airway space measurement. The lower oropharyngeal airway space measurement showed a statistically significant difference among the groups, with the smallest dimension observed in the skeletal class II, division 2 group. Conclusion: The naso-oropharyngeal airway dimensions showed a statistically significant difference among the class II, division 1; class II, division 2; and class I groups during different growth periods.

• 대한치과교정학회지
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• 제48권5호
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• pp.333-338
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• 2018

Objective: The aim of this study was to compare the buccolingual inclination of maxillary and mandibular molars in adults with different vertical facial types. Methods: Cone-beam computed tomography images of 135 adult patients (age, 20-45 years) with skeletal Class I maxillomandibular relationships were assigned to normodivergent (n = 46), hypodivergent (n = 49), and hyperdivergent groups (n = 40) according to linear and angular sella-nasion/gonion-menton measurements. The normodivergent group consisted of 24 females and 22 males, hypodivergent group of 26 females and 23 males, and hyperdivergent group of 24 females and 16 males. Buccolingual inclination of the maxillary and mandibular first and second molars was measured relative to the occlusal plane. One-way analysis of variance was used for intergroup comparison. Gender differences were evaluated using independent t-tests. Results: Buccolingual molar inclinations did not differ significantly between females and males (p > 0.05). There were no statistically significant differences among the buccolingual inclinations of the first and second maxillary and mandibular molars of the groups (p > 0.05). Conclusions: Buccolingual inclinations of maxillary and mandibular molars are similar in normodivergent, hyperdivergent, and hypodivergent adults with Class I sagittal relationships.

• 치과방사선
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• 제21권1호
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• pp.127-135
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• 1991

This study purports to make in consideration of the recent xeroradiographic development an exact analysis, by comparison, of conventional cephalometry and xeroradiographic cephalometry that are indispensably utilized in the field of orthodontics as a means of cephalometric measuring For that purpose attached to ten landmarks on a dry skull was a lead ball, a radio-opaque substance, and projected X-ray beam one time each by means of the two methods, and then ten times each without change of locations of the skull, in the state in which the lead ball was removed. These data were committed to ten dentists for tracing to determine a difference between the same kind of cephalometries. A computerized statistic analysis of the data shows findings, as follows: 1. Conventional cephalometry shows higher accuracy in Nasion, as compared with xeroradiographic cephalometry. 2. Xeroradiographic cephalometry is found more accurate in Anterior Nasal Spine, 'A' Point, Pogonion, Gonion, Porion, Prosthion and Orbitale than conventional cephalometry. 3. There is no difference between both methods in Basion. 4. At test between the two methods by all the dentists reveals that xeroradiographic cephalometry is more accurate than conventional cephalometry.

• Imaging Science in Dentistry
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• 제40권2호
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• pp.83-87
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• 2010

Purpose : This study was to determine the relationship between age and the mandibular cortical bone thickness on panoramic radiograph. Materials and Methods : Panoramic radiographs of 360 patients (180 men and 180 women) over 20 years old, who visited the Chonbuk National University Hospital from January to December in 2007, were assessed. The subjects were divided into 5 age groups. Five indices such as cortical bone thickness at the gonion (GI), antegonion (AI), and below the mental foramen (MI), the panoramic mandibular index (PMI), the mandibular cortical index (MCI) were measured on panoramic radiographs. Results : All five indices including GI, AI, MI, PMI, and MCI showed significant differences between third decade and over 8 decade groups (p<0.05). PMI, MI and GI showed significant differences with gender statistically (p<0.05). Conclusion : The mandibular cortical bone thickness showed negative correlation with age, and the value of the thickness (PMI, MI, and GI) was greater in men than in women.

• 대한구순구개열학회지
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• 제4권2호
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• pp.45-50
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• 2001

Recents reports have demonstrated that force and direction is important during mandibular distraction osteogenesis. The purpose of this study was to evaluate the resistant force of internal pterygoid muscles and inquire into relationship between internal pte'Ygoid muscles and cephalometric parameters. Eighty four patients with class III malocclusion underwent bilateral sgittal splitting of ramus with intraoral vertico-sagittal ramal osteotomy. A spring scale were used for measuring for resistence of internal pterygoid mescles after splitting of ramus. Skeletal-dental cephalometric analysis was made following statistic package was used for correlation between resistence and cephalometric parameters. The resistant force of right internal pterygoid muscle was greater than left muscle in Korean with class III malocclusion and the force had a linear regression relationship with facial depth (distance between nasion and gonion). The results suggested that facial depth has significant correlation of the resistance of internal pterygoid muscle (p<0.05).

• Maxillofacial Plastic and Reconstructive Surgery
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• 제23권1호
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• pp.7-14
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• 2001

Purpose : The lateral cephalometric Korean norms of the skeletal and pharyngeal dimension were analyzed for the diagnosis of obstructive sleep apnea syndrome(OSAS). Materials and Methods : The lateral cephalometric radiographies were taken in male(n=53) and female(n=50), who had a normal profile, class I occlusion, normal ANB $(0{\sim}4^{\circ})$ and normal Wits $Appraisal(-4{\sim}0mm)$. The X-rays were traced by two oral and maxillofacial surgeons twice. The significant differences between male-female and examiners were tested. Results : The angle of mandibular line to Nasion-Sella line was $31.12^{\circ}/33.79^{\circ}$ (in male/in female, p=0.0018). The lower Gonion angle was $73.74^{\circ}/73.74^{\circ}(p=0.9978)$. The length of the soft palate was 36.93mm/34.35mm(p=0.0002). The pharyngeal airway space was 13.42mm/11.55mm at mandibular plane level(PAS(ML))(p=0.0025). The hyoid was placed inferiorly to mandibular plane 10.18mm/7.72mm(p=0.0051). The results from this study are to be used for the diagnosis of OSAS.

• 대한치과교정학회지
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• 제42권2호
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• pp.73-79
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• 2012

Objective: The purpose of this study was to investigate the effects of a newly developed rapid maxillary expansion screw-the memory screw-over 6 months. Methods: Five subjects, aged between 11.7 and 13.75 years, were enrolled in this study. All subjects underwent placement of a maxillary expansion appliance containing superelastic nickel-titanium open-coil springs in its screw bed. The parents of the patients and/or the patients themselves were instructed to activate the expansion screw by 2 quarter-turns 3 times a day (morning, midday, and evening; 6 quarter-turns a day). The mean expansion period was $7.52{\pm}1.04$ days. Dentoskeletal effects of the procedure, including dentoalveolar inclination, were evaluated. Measurements of all the parameters were repeated after 6 months of retention in order to check for relapse. Results: Sella-Nasion-A point (SNA) and Sella-Nasion/Gonion-Menton angles increased, and Sella-Nasion-B point (SNB) angle decreased in all the subjects during the expansion phase. However, they approximated to the initial values at the end of 6 months. On the other hand, the increments in maxillary apical base (Mxr-Mxl) and intermolar widths was quite stable. As expected, some amount of dentoalveolar tipping was observed. Conclusions: The newly developed memory expansion screw offers advantages of both rapid and slow expansion procedures. It widens the midpalatal suture and expands the maxilla with relatively lighter forces and within a short time. In addition, the resultant increments in the maxillary apical base and intermolar width remained quite stable even aft er 6 months of retention.

• 대한치과교정학회지
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• 제9권1호
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• pp.133-140
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• 1979

The author compared patients showing two extremes of incisor vertical relationship to find out differences in craniofacial morphology which might influence face height and incisor overbite. The subjects consisted of 53 open-bite cases and the same number of deep-bite cases. The results were as follows: 1. On the average, the lower face height was significantly greater in open-bite cases than in deep-bite cases. 2. In open-bite cases, gonin-menton length was significantly greater than in deep-bite cases. In deep-bite cases, anterior cranial base length and posterior cranial base length were significantly greater in open-bite cases. 3. The jaw angle was significantly greater in open-bite cases. 4. The gonion-menton-nasion angle was significantly greater in deep-bite cases. 5. From geometric standpoint, the increase of jaw and joint angle would increase lower face height, but these two showed negative correlation. 6. The sizes of the jaw and joint angle might be factors of open-bite or deep-bite, but these were not the only variables that determined lower face height. 7. In open-bite cases, there was a closer correlationship between lower face height and the other linear measurments than in deep-bite cases. In deep-bite cases, there was a closer correlationship between lower face height and the other angular measurements than in open-bite cases. 8. Considering both linear and angular measurements of facial polygon, all contributed significantly to the lower face height. The nonsignificant variables were jaw and joint angle in open-bite cases, and anterior cranial base length, jaw angle, and joint angle in deep-bite cases.

• Imaging Science in Dentistry
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• 제46권2호
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• pp.77-85
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• 2016

Purpose: To analyze the relative position of the mandibular foramina (MnFs) in patients diagnosed with skeletal class III malocclusion. Materials and Methods: Computed tomography (CT) images were collected from 85 patients. The vertical lengths of each anatomic point from the five horizontal planes passing through the MnF were measured at the coronoid process, sigmoid notch, condyle, and the gonion. The distance from the anterior ramus point to the posterior ramus point on the five horizontal planes was designated the anteroposterior horizontal distance of the ramus for each plane. The perpendicular distance from each anterior ramus point to each vertical plane through the MnF was designated the horizontal distance from the anterior ramus to the MnF. The horizontal and vertical positions were examined by regression analysis. Results: Regression analysis showed the heights of the coronoid process, sigmoid notch, and condyle for the five horizontal planes were significantly related to the height of the MnF, with the highest significance associated with the MnF-mandibular plane (coefficients of determination ($R^2$): 0.424, 0.597, and 0.604, respectively). The horizontal anteroposterior length of the ramus and the distance from the anterior ramus point to the MnF were significant by regression analysis. Conclusion: The relative position of the MnF was significantly related to the vertical heights of the sigmoid notch, coronoid process, and condyle as well as to the horizontal anteroposterior length of the ascending ramus. These findings should be clinically useful for patients with skeletal class III mandibular prognathism.