• 대한치과의사협회지
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• 제56권2호
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• pp.94-102
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• 2018

The present study was conducted to assess the growth changes of human chin in childhood and adolescence at various stages of skeletal maturation using metallic implant installed in mandibular body. Lateral cephalographs including 23 subjects (9 males and 14 females) between 7-18 years old were used, which had been taken at University of California in San Francisco and kept at University of the Pacific. Three lateral cephalographs were chosen for each subject according to CVM (Cervical Vertebral Maturation) method (CVM stage 1 to 2, CVM stage 3 to 4, and CVM stage 5 to 6) which assess the extent of the skeletal maturation using the second, third, and fourth cervical vertebrae. V-ceph was used in order to mark the 8 landmarks (S, N, A, B, Pog, Me, Go, Imp) on lateral cephalographs and obtain 8 angular and linear measurements(ANB, SNPog, SN-GoMe, Imp-B, Imp-Pog, B-Pog//GoMe, $GoMe{\bot}B$, $GoMe{\bot}Pog$). Among 8 measurements, ANB, SNPog, SN-GoMe, B-Pog//GoMe, $GoMe{\bot}B$ showed statistically significant growth changes at various stages of skeletal maturation according to CVM method, while there were no significant differences on Imp-B, Imp-Pog, $GoMe{\bot}Pog$. The results suggest that the increasing prominence of human chin is greatly influenced by the vertical growth of B point area, in addition to the change and growth in chin and mandible proper.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제28권5호
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• pp.372-382
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• 2002

As the most of dentofacial deformity patients indicated to orthognathic surgery have strong desire for esthetic improvement as well as functional improvement, ideal esthetic evaluation should be made at surgical prediction. Lateral cephalographs has been commonly used for surgical prediction, however, remarkable discrepancy between esthetic viewpoint by simple looking and analysis on lateral cephalographs often found on evaluation of sagittal position of the upper and lower jaws especially in cases of mandibular prognathism of Koreans. In these cases, we have been employed Esthetic NaP(ENaP)-line for corrective evaluation and ideal surgical prediction on lateral cephalographs, but the efficacy of ENaP-line has not been evaluated. This is a study on efficacy of ENaP-line for orthognathic surgery of Korean mandibular prognathism. 170 Korean patients who had been diagnosed as mandibular prognathism and planned for orthognathic surgery at Department of Oral and Maxillofacial Surgery, College of Dentistry, Yonsei University during last 10 years are studied. The obtained results are as followings; among 170 patients of mandibular prognathism, 132 patients(77.6%) had not discrepancy in evaluation of sagittal position of the maxilla between cephalometric and esthetic evaluation(they are classified as Group I), however, 38 patients(22.4%) had definite discrepancy(they are classified as Group II). ENaP-line was employed in all cephalometric analysis of Group II. The proportions of male and female were similar in both Groups. Sixteen vertical reference lines perpendicular to 16 horizontal reference lines were obtained as followings; Each of the representative degree of ${\angle}SN/AFH$, ${\angle}SN/CFH$ and ${\angle}AFH/CFH$ obtained at Group I was applied to SN plane, AFH plane and CFH plane of Group II each other, and so 16 horizontal reference lines could be obtained individually according to each of the applied degree to each plane. And then their reliability to coincide with ENaP-line of Group II was evaluated. A vertical reference line perpendicular to a horizontal line made by application of the representative degree of ${\angle}$AFH/CFH in Group I to AFH line in Group II had the most highest coincidence with ENaP-line of Group II, however, its agreement was 42% in male and 47% in female. From this results, the rest of them should be determined their corrective jaw position definitely depend on

• Imaging Science in Dentistry
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• 제31권4호
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• pp.205-207
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• 2001

Purpose : The aim of present study is to estimate the relationship among reference lines used for taking the extraoral radiography and panoramic radiography. Materials and Methods: Lateral cephalographs of 40 adults, aged 22 to 30 years were taken. Angles between reference lines (Frankfort line, canthomeatal line, infraorbitomeatal line, and occlusal plane) were measured. Results: Angles between Frankfort line and canthomeatal line, Frankfort line and infraorbitomeatal line, Frankfort line and occlusal plane, canthomeatal line and infraorbitomeatal line, canthomeatal line and occlusal plane, and infraorbitomeatal line and occlusal plane were 16.1° (±2.2), 5.8° (±2.4), 8.7° (±3.5), 10.3° (±1.3), 24.8° (±4.0), and 14.5° (±4.4),respectively. Conclusion: Angle between frankfort and canthomeatal line is very different with commonly known angle. Frankfort horizontal reference lines used for panoramic radiography need an exact definition and more accurate standard is needed for the taking of panoramic radiograph.

• 대한치과의사협회지
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• 제25권9호통권220호
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• pp.847-854
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• 1987

Genioplasty may considerably change a person's face which needs surgical correction of deformed chin. Comprehensive treatment planning is therefore decisive for the treatment to be successful. A three-dimensional analysis of chin relative to cranial base, upper and lower jaws using the frontal and lateral facial photographs and cephalographs permits classification of the defective chin position and provides a basis for operation planning and deciding upon the operation method. A chin miniplate system has been developed for intraoperative registration securing the sagittal, vertical and horizontal position of the osteotomized chin and ould reduce the relapse rate.

• 대한두개안면성형외과학회지
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• 제12권1호
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• pp.6-11
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• 2011

Purpose: The cephalic index (CI) is used to classify the head and every race has its unique characteristics. Previous studies published in Korea were limited to demonstrating the periodical change of the CI. This study was done to determine the CI change in 0 to 20 year-old Koreans by sex and age. Methods: The measurement was done on 1,222 Koreans ranging from 0 to 20 years of age, randomly selected from 2,156 who were diagnosed with simple concussion, had no other diseases or anomalies, and took cephalographs from January, 2000 to July, 2008. The files were obtained from $Marosis^{(R)}$ and then photogrammetry was done by $Photoshop^{(R)}$. To standardize the cephalograph, the Frankfort horizontal line was selected as the reference line on lateral view and the line connecting both lateral-orbitales on AP view. The maximal length was obtained from the lateral cephalograph and the maximal breadth from the AP cephalograph. Results: The CI showed no difference by sex (p=0.4848). The CI and age showed negative correlation (p<0.0001). Analyzed separately by the male and the female, the CI showed statistical significance in the male (p<0.0001), but not in the female (p=0.4741) group. Comparing the CI above the age of 11, the CI of the female became greater than that of the male. Conclusion: This study contributes to the standardization of CI measurement and the authors were able to obtain the average CI by age. We concluded that the CI decreased according to age and most Koreans belonged to barchycephalic or hyperbrachycephalic.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제27권1호
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• pp.48-54
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• 2005

This is to evaluate the postoperative cephalometric changes of the chin advanced by the genioplasty. Thirty-eight patients who underwent advancement genioplasties at Ewha Womans University Mokdong Hospital between January of 2001 and February of 2003. They were followed up for at least 12 months with lateral cephalographs. The remodelling changes of the horizontal linear measurement between the Pogonion and Perpendicular line to FH plane were measured and analysed by Independent sample tests. The chin advancement resulted in $1.3{\pm}0.3mm$ resorption (28.2% of advancement) after 6 months, but in $1.4{\pm}0.2mm$ after 1 year. If the chin was advanced less than 3 mm, remodelling followed by $1.2{\pm}0.2mm$ reduction, but $1.3{\pm}0.3mm$ reduction followed after chin advanced over 4 mm. There were no significant differences in the amount of bone resorption by the gender, number of genial cut-steps and acompanied osteotomies.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제21권3호
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• pp.288-297
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• 1999

This study has been carried out in order to measure the thickness of soft-tissue on lateral cephalographs based on body mass index(BMI) and the change in soft-tissue thickness after surgical correction of mandibular protrusion. The control material in cephalometric study comprised students at The Dental College, 38 persons, aged 21~24 years and the patient material comprised 20 women and 12men, aged 19~28 years with mandibular protrusion.The thickness of the soft-tissue based on BMI in control and study groups, the comparison between them, immediate postoperative change in the thickness, 6 months after surgery, ratio of soft-tissue response and correlation was established through various statistical methods. The result were as follows : 1. The groups based on BMI showed significant differences each other as regards the linear measurements. The thickest soft-tissue was measured 13.6mm, 15.47mm, 16.76mm at Ss, the thinnest at G' 6.0mm, 6.7mm, 7.26mm respectively. 2. The differences between control and experimental groups based on BMI showed to be significant. There were no differences at G'. The soft-tissue in prognathic patients was thicker at Ss, Ls and thinner at Li, Ls, Pg', Gn', Me'. Differential gap was greater in overweight groups. 3. The immediate soft-tissue change after surgery showed the increase at Li, Ls, Pg', Gn', Me' except G', Ls in all groups. 4. The postoperative soft-tissue change 6 months after surgery was similar with immediate change. The soft-tissue shows the increase in the thickness at Li, Pg', Gn', Me' and the greatest difference occurred at Li, 1.1mm, 0.98mm, 1.2mm respectively. 5. The patients with lower BMI index showed higher soft-tissue response to bony movement at Pg'. The immediate response ratio was 91%, 87%, 81% in A,B,C groups respectively, the response 6 months after surgery showed 96%, 91%, 84%.

• 대한치과교정학회지
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• 제48권4호
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• pp.224-235
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• 2018

Objective: The purpose of this study was to compare the skeletal, dental, and soft-tissue treatment effects of nonextraction therapy using the modified C-palatal plate (MCPP) to those of premolar extraction (PE) treatment in adult patients with Class II malocclusion. Methods: Pretreatment and posttreatment lateral cephalographs of 40 adult patients with Class II malocclusion were retrospectively analyzed. The MCPP group comprised 20 patients treated with total arch distalization of the maxillary arch while the PE group comprised 20 patients treated with four PE. Fifty-eight linear and angular measurements were analyzed to assess the changes before and after treatment. Descriptive statistics, paired t-test, and multivariate analysis of variance were performed to evaluate the treatment effects within and between the two groups. Results: The MCPP group presented 3.4 mm of retraction, 1.0 mm of extrusion, and $7.3^{\circ}$ lingual inclination of the maxillary central incisor. In comparison, the PE group displayed greater amount of maxillary central incisor retraction and retroclination, mandibular incisor retraction, and upper lip retraction (5.3 mm, $14.8^{\circ}$, 5.1 mm, and 2.0 mm, respectively; p < 0.001 for all). In addition, the MCPP group showed 4.0 mm of distalization and 1.3 mm of intrusion with $2.9^{\circ}$ distal tipping of the maxillary first molars. Conclusions: These findings suggest the MCPP is an effective distalization appliance in the maxillary arch. The amount of incisor retraction, however, was significantly higher in the PE group. Therefore, four PE may be recommended when greater improvement of incisor position and soft-tissue profile is required.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제46권1호
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• pp.41-48
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• 2020

Objectives: One of the most common complications of bilateral sagittal split ramus osteotomy (BSSRO) is neurosensory impairment of the inferior alveolar nerve (IAN). Accurate preoperative determination of the position of the IAN canal within the mandible using cone-beam computed tomography (CBCT) is recommended to prevent IAN dysfunction during BSSRO and facilitate neurosensory improvement after BSSRO. Materials and Methods: This randomized clinical trial consisted of 86 surgical sites in 43 patients (30 females and 13 males), including 21 cases (42 sides) and 22 controls (44 sides). Panoramic and lateral cephalographs were obtained from all patients. In the experimental group, CBCT was also performed from both sides of the ramus and mandibular body. Neurosensory function of the IAN was subjectively assessed using a 5-point scale preoperatively and 7 days, 1 month, 3 months, 6 months, and 12 months post-surgery. Data were analyzed using Fisher's test, Spearman's test, t-test, linear mixed-model regression, and repeated-measures ANCOVA (α=0.05, 0.01). Results: Mean sensory scores in the control group were 1.57, 2.61, 3.34, 3.73, and 4.20 over one year and were 1.69, 3.00, 3.60, 4.19, and 4.48 in the CBCT group. Significant effects were detected for CBCT intervention (P=0.002) and jaw side (P=0.003) but not for age (P=0.617) or displacement extent (P=0.122). Conclusion: Preoperative use of CBCT may help surgeons to practice more conservative surgery. Neurosensory deficits might heal faster on the right side.

• The Journal of Advanced Prosthodontics
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• 제5권1호
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• pp.58-66
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• 2013

PURPOSE. The purpose of this study was to decide the most appropriate point on tragus to be used as a reference point at time of marking ala tragus line while establishing occlusal plane. MATERIALS AND METHODS. The data was collected in two groups of subjects: 1) Dentulous 2) Edentulous group having sample size of 30 for each group with equal gender distribution (15 males, 15 females each). Downs analysis was used for base value. Lateral cephalographs were taken for all selected subjects. Three points were marked on tragus as Superior (S), Middle (M), and Inferior (I) and were joined with ala (A) of the nose to form ala-tragus lines. The angle formed by each line (SA plane, MA plane, IA plane) with Frankfort Horizontal (FH) plane was measured by using custom made device and modified protractor in all dentulous and edentulous subjects. Also, in dentulous subjects angle between Frankfort Horizontal plane and natural occlusal plane was measured. The measurements obtained were subjected to the following statistical tests; descriptive analysis, Student's unpaired t-test and Pearson's correlation coefficient. RESULTS. The results demonstrated, the mean angle COO (cant of occlusal plane) as $9.76^{\circ}$, inferior point on tragus had given the mean angular value of IFH [Angle between IA plane (plane formed by joining inferior point-I on tragus and ala of nose- A) and FH plane) as $10.40^{\circ}$ and $10.56^{\circ}$ in dentulous and edentulous subjects respectively which was the closest value to the angle COO and was comparable with the values of angle COO value in Downs analysis. Angulations of ala-tragus line marked from inferior point with occlusal plane in dentulous subject had given the smallest value $2.46^{\circ}$ which showed that this ala-tragus line was nearly parallel to occlusal plane. CONCLUSION. The inferior point marked on tragus is the most appropriate point for marking ala-tragus line.