• The Journal of the Korean dental association
• /
• v.42 no.2 s.417
• /
• pp.68-75
• /
• 2004

• The Journal of the Korean dental association
• /
• v.18 no.1 s.130
• /
• pp.41-46
• /
• 1980

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.32 no.2
• /
• pp.132-140
• /
• 2010

Purpose: The aim of this study is to identify the usefulness of unilateral mandibular angle ostectomy, so-called "Lateral Angle Reduction", in asymmetric prognathism patients by the assessment of postoperative stability and esthetic results Patients and methods: For the retrospective study, 10 skeletal class III mandibular asymmetry patients who were performed SSRO and unilateral mandibular angle ostectomy, Lateral Angle Reduction, was selected. Lateral and posterioanterior cephalogram was taken before surgery (T0), 1day after surgery (T1) and 6month after surgery (T2). To know the esthetic results the facial width and lateral facial contour were examined on posterioanterior cephalogram and to know the postoperative stability B point and Incisor inferius was examined on lateral cephalogram. Statistical analysis was performed. Results: From T0 to T1, Intergonial width was significantly decreased, dominantly at shortened side but no significant changes at lengthened side. Those were well-maintained during 6 months. Lateral facial angle and Ramus angle was significantly decreased on only shortened side from T0 to T1. As a result, after surgery, there were no significant differences in all measurements between shortened side and lengthened side. Ramus deviation angle in shortened side and ramus angle in lengthened side which reflect the angulation of ramus on frontal plane didn't show significant changes after surgery and during postsurgical periods. Lower dental midline showed no statistical changes during postsurgical period. The relapse rate on B-point was 11.92%. Conclusion: Unilateral "Lateral angle reduction" in the asymmetric mandible is valuable to obtain the narrow lower face and symmetric facial contour with a good stability.

• The korean journal of orthodontics
• /
• v.17 no.1
• /
• pp.135-148
• /
• 1987

To investigate the relationship between craniofacial growth and bone maturity of the hand wrist in normal occlusion, the author took cephalogram and handwrist radiogram of 391 students (male 192, female 199) and assessed the measurements of cephalogram according to skeletal maturity stages of the hand and wrist. In this study, four skeketal stages and 36 linear, angular measurements of the cephalometrics were selected. In hand-wrist X-ray the bones used to determine skeletal maturity were the middle phalanges of the third finger, and distal epiphysis of the radius. In cephalogram, the landmark used to measure the angle and length were N, S, Po., Ar., Go., Me., Gn., Pog., Point B, Point A, ANS, PNS, Or., U1, L1, U6, L6 etc.. The results were as follows, 1. The table of mean, standard deviation, p-value from measurements were made in each group and both sex. 2. The increased measurements according to skeletal maturity were anterior cranial bese length, posterior cranial base length, ramus height, anterior facial height, posterior facial height, L1 to mandibular plane (mm), facial plane angle. In contrast to, decreased measurements were genial angle, facial cnvexity and facial plane angle. 3. Denture pattern measurements (IMPA, FMIA, occlusal plane to Go-Gn, interincisal angle, U1 to SN plane, U1 to SN plane, U1 to facial plane, L1 to facial plane etc.) .had nothing to do with skeletal maturity. 4. Skeletal maturity had close relationship with craniofacial growth, but had little to do with tooth development.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.33 no.4
• /
• pp.346-351
• /
• 2011

Purpose: The purpose of this study was to measure the angular differences between the horizontal reference planes on the CBCT generated PA cephalogram and the modified interpupillary plane, which was usually used in the clinical examination, and to evaluate the validity of the horizontal reference planes. Methods: The CBCT generated PA cephalogram was used to measure the angles between the FH, Lo and IP planes. The subjects consisted of 42 patients with facial asymmetry (males: 21, females: 21, mean-age: 21.6 years). The control groups were also assessed (males: 10, females: 10, mean-age: 23.8 years). The distance of the interpupil was measured on the soft-tissue volume rendered image. The angular differences were statistically analyzed using the $Mann-Whitney$ $U$ $test$ for inter-group comparisons and the $Friedman$ $test$ for intra-group comparisions. Results: The angle between the FH plane and IP plane (the angle of the FH-IP line) showed a statistically significant difference between the two groups ($p$ <0.05). There was no statistical differences between each angle (angle of the FH-IP line, angle of the FH-Lo line, angle of the Lo-IP line) on the intra-group comparision ($p$ >0.05). Conclusion: The angle between the Lo line and IP line (angle of the Lo-IP line) showed no statistically significant difference in both the control and asymmetry groups. Therefore, the Lo line could be used as a horizontal reference plane in CBCT generated PA cephalograms.

• The korean journal of orthodontics
• /
• v.25 no.4
• /
• pp.487-495
• /
• 1995

This study was undertaken to compare each maximum biting force and to investigate its relationship with the facial skeketal form, number and position of tooth contact between anterior openbite and normal occlusion adults, using the T-scan system and the lateral cephalogram. The subjects of this study consisted of a group of 25 individuals with normal occlusion and another group of 14 with anterior openbite. The obtained results of this study were as follows : 1. The maximum biting force of anterior openbite adults was less than that of normal occlusion adults. 2. In anterior openbite adults, there were negative correlations between the maximum, biting force and SN/MP, FMA, PP/MP mesurement of lateral cephalogram. 3. In anterior openbite adults, as the mesial angulation of lower first molar against the occlusal plane increased, the more the biting force decreased. 4. In both groups, the greater the number of tooth contact, the more the biting force increased. 5. In both groups, the center of effort for anteroposterior occlusal contact was located on the first molar region.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.29 no.3
• /
• pp.173-181
• /
• 2003

Purpose : This study was intended to evaluate the positional relationship between the hyoid bone and the mandible in patients with mandibular protrusion after mandibular set-back surgery by means of 3D-CT. Materials and methods : Preoperative(3 weeks before) and postoperative (6 weeks after) 3D-CT & cephalogram were taken on 32 patients(12 male, 20 female, mean age of 23.2) treated by bilateral sagittal split osteotomy with rigid fixation. The angular measurement on 3D-CT basilar view were deviation of Me & H, long axis angle of left & right cornu majus. The lineal measurement on 3D-CT basilar view were composed of intercondylar line and coordinates(x,y) of Me & H. The angular & lineal measurement of lateral cephalogram were composed of mandibular plane angle, SNA, SNB, ANB, FH-NA & FH-NB, and coordinates(x,y) of B, Pog, Me & H, PAS, Lpw, MPH and IAS. On the frontal cephalogram, deviation of Me were evaluated. Results : The mean mandibular set-back was 8.0mm horizontally and mandibular plane angle was slightly increased. The hyoid bone was displaced postero-inferiorly, the distance between MP(mandibular plane) and H(hyoid bone) was increased and the posterior airway space values (PAS, Lpw, IAS) were decreased. The coordinates Me(x,y), H(x,y) and deviation angle Me'& H' were revealed the strong positive correlation. Conclusion : The results revealed that the horizontal, vertical and transverse relationship of the mandibular and the hyoid bone movements were significantly correlated in patients performed mandibular set-back surgery.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
• /
• v.12 no.1
• /
• pp.49-56
• /
• 1982

The purpose of this study was to observe the anatomic variation of condylar head and the positional relationship between condylar head and other anatomic structures of head by means of cephalometry using the submentovertex cephalogram from each person in centric occlusion for producing a good quality of temporomandibular joint radiograph. The 100 submentovertex cephalograms of 100 Korean adults consisted of 50 females ranged from 20 to 24 years age and 50 males ranged from 22 to 30 years age, were studied and analyzed statistically. The results were as follows; 1. The mean of the horizontal angulation of condylar head to the transmeatal line (EE-LA) was 18.5° (S.D. 7.9°), and all measurements that indicate the horizontal angulation of condylar head showed considerable differences among individuals. 2. In the comparison of male vs. female in the measurements, statistically significant differences were found in the majority of measurement items, and with exception of R-LA and LA-LA, the rest of these measurements were larger in male than in female. 3. In the comparison of left vs. right in the measurements, statistically significant differences were found in the majority of measurement items, and with exception of PC-CC, the rest of these measurements were larger in right than in left. As above, because the majority of measurements that involve the horizontal angulation of condylar head varied among individuals, between male and female, and between left and right, the condition of various temporomandibular joint radiography should be determined by means of cephalometry using the submentovertex cephalogram for producing the accurate radiographic image of temporomandibular joint.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.21 no.2
• /
• pp.174-188
• /
• 1999

The purpose of this study is to evaluate the precision and accuracy of a three dimensional cephalogram constructed by using the frontal and lateral cephalogram of twelve human dry skulls. After achieving the three dimensional image reconstruction program, we tried to apply this program to two dentofacial deformity patients. 1. Conventional nasion relator in cephalostat was used to reproduce the same head position for the same dry skull. The mean difference of the three dimensional cephalogram for the same dry skull was $0.34{\pm}0.33mm$. Closeness of repeated measures to each skull reveals the precision of this method for the three dimensional cephalogram. 2. Concerning the accuracy, the mean difference between the three dimensional reconstruction data and actual lineal measurements was $1.47{\pm}1.45mm$ and the mean magnification ratio was $100.24{\pm}4.68%$. This Diffrerence is attributed mainly to the ill defined cephalometric landmarks, not to the positional change of the dry skull. 3. Cephalometric measurement of lateral and frontal radiographs had no consecutive magnification ratio because of the different focus-object distance. The mean difference between the frontal and lateral cephalogram to the actual lineal measurements was $4.72{\pm}2.01mm$ and $-5.22{\pm}3.36mm$. Vertical measurements were slightly more accurate than horizontal measurements. 4. Applying to the actual patient analysis, it is recommendable to use this program for analyzing the asymmetry or spatial change after operation. The orthodontic bracket would be a favorable cephalometric landmark for constructing the three dimensional images.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.29 no.5
• /
• pp.338-345
• /
• 2003

Purpose : This study was intended to perform cephalometric comparison between the patients with and without obstructive sleep apnea (OSA). The factors influencing the OSA in the lateral cephalogram was also investigated. Patient and Method : Twenty four patients who visited Sleep Disorder Clinic in Dongsan Medical Center, Keimyung University and evaluated with polysomnograph(PSG) and cephalogram were included in the study. The patients had apnea-hypopnea episode(AHI) over 10 times per hour was diagnosed as OSA after overnight PSG. To evaluate hard and soft tissue profile, cephalometric radiogram were taken at maximal intercuspation(P1) and mandibular protruding position(P2). The diffefence between the OSA and normal group were evaluated statistically and the stepwise regression analysis was applied to analyse the cephalometric influencing factors to OSA. Result : The OSA Group(n=14) had significantly higher Body Mass Index(BMI) than control group(n=10). Lower facial height(ANSGn) was longer in OSA group. However statistically significant difference was not detected in other anteroposterior craniofacial measurements. The soft palate lenth (PNS-P), hyoid position (MP-Hyoid) had positive correlation between AHI (r=0.496, r=0.413, respectively, p<0.05). However, the measurements of oropharyngeal airway was not different between the two groups. The hypothesis, the antero-posteriorly narrow oropharyngeal airway might aggravate the airway resistance and can give rise to higher AHI, was not accepted in the study. This can be attributed by inclusion of the patients performed uvulopalatopharyngoplasty because of the tonsilar or soft palate hypertrophy in the present study. The results of regression analysis revealed that PNS-P, upper airway width(Nph1), upper facial heght(N-ANS), and lower facial height(ANS-Gn) could influence the degree of AHI (F value < 0.0001, $R^2$ = 0.829). Conclusion : We suggest lateral cephalogram may utilized as a useful method to evaluate OSA. The patient with long soft palate, narrow upper airway width, long upper & lower facial height can be expected to have high risk of OSA. However, it should be emphasized the comphrehensive intraoral inspection including soft palate and tonsilar hypertrophy because lateral cepahlogram cannot visualize oropharyngeal status completely.