• The korean journal of orthodontics
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• v.36 no.5
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• pp.380-387
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• 2006

Objective: The purpose of this study was to compare the right and left differences of frontal ramal inclination in chin-deviated individuals. Methods: Thirty adult patients with clinically apparent chin deviation were selected as the chin-deviated group, and 30 adult patients with symmetric faces were selected as the control group. On the posteroanterior cephalograms, the frontal ramal inclination was measured, and the right and left differences were compared and analyzed. Results: While the control group did not show right and left differences of frontal ramal inclinations, the chin-deviated individuals showed right and left differences of frontal ramal inclination. In chin-deviated individuals, the frontal ramal inclinations of the non-deviated side were statistically greater than those of the deviated side. The right and left differences of frontal ramal inclinations, with menton deviation and the right and left differences of maxillary heights showed statistically significant correlation. Conclusion: We conclude that the frontal ramal inclinations should be considered in the diagnosis of facial asymmetry.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.1
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• pp.21-29
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• 2011

Introduction: To compare the change in frontal ramal inclination (FRI) in laterognathism after orthognathic surgery. Materials and Methods: Twenty four patients (10 men, 14 women; mean age, $22.8{\pm}5.2$ years) with minimal facial canting (${\leq}$ 2 mm) and apparent menton deviation ($5.9{\pm}2.4\;mm$) who had been operated on to correct facial asymmetry and skeletal CIII malocclusion, were selected. On a preoperative posteroanterior (PA) cephalogram, the FRI of the deviated side and non deviated side, L1 deviation amounts and menton deviation amounts were measured. The FRI differences between both sides were compared, and the correlations between the measured deviated elements and the FRI differences were analyzed. On a postoperative PA cephalogram, the shifting amount of L1, shifting amount of L7 and FRI of both sides were measured, and the correlations between the shifting elements and the change in FRI were analyzed. Results: On the preoperative PA cephalogram, the FRI of the non deviated side was significantly greater than those of the deviated side. The differences in FRI, with a menton deviation amount showed a significant correlation. On the postoperative PA cephalogram, the FRI differences between the deviated and non deviated side were decreased significantly and mandibular transverse movement toward central position was noted. The mean shifting amounts of L7 were associated with the amount of change in the deviated side of FRI. Conclusion: Transverse shifting of the mandible through orthognathic surgery decreases the FRI difference, which showed laterognathism, and improves the facial contour.

• The korean journal of orthodontics
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• v.35 no.2 s.109
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• pp.91-105
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• 2005

For af accurate diagnosis and treatment planning of facial asymmetry, the use of 3-dimensional (3-D) image is indispensable. The purpose of this study was to get standard data for the 3-D analysis of facial asymmetry Computerized tomography (CT) was taken in the 60 normal occlusion individuals (30 male. 30 female) who did not have any apparent facial asymmetry. The acquired 2D CT DICOM data were input on a computer, and the reformatted 3-D images were created using a 3-D image software. Twenty three measurements were established in order to evaluate asymmetry; 15 ;omear measurements (6 for ramus length. 1 for condylar neck length, and 8 for mandibular body length) and 8 angular measurements (4 for gonial angle. 2 for frontal ramal inclination. and 2 for lateral ramal inclination) The right aid left difference of each measurement was calculated and analyzed. It is suggested that the right and left differences of the measurements obtained from the study could be used as references for the diagnosis of facial asymmetric patients.

• The korean journal of orthodontics
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• v.35 no.3 s.110
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• pp.163-173
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• 2005

The purpose of this study was to compare the asymmetric degree between maxillofacial hard and soft tissues in individuals with facial asymmetry. Computerized tomographies (CT) of 34 adults (17 male, 17 female) who had facial asymmetry were taken. The CT images were transmitted to personal computers and then reconstructed into three-dimensional (3D) images through the use of computer software. In order to evaluate the degree of facial asymmetry, 6 measurements were constructed as the hard tissue measurements while 6 counterpart measurements were taken as the soft tissue measurements. The means and standard deviations were obtained for each measurement using 3D measure, then t-test was used to investigate the differences between each hard tissue measurement and the corresponding soft tissue measurement All measurements used in the present study showed statistically significant differences between the hard and soft tissues. The degree of soft tissue asymmetry was smaller than that of corresponding hard tissue asymmetry in case of chin deviation, frontal ramal inclination difference, and frontal corpus inclination difference. On the other hand, the degree of soft tissue asymmetry was greater than that of underlying hard tissue asymmetry in the measurement of lip canting and lip cheilion height difference The present study suggests that asymmetric differences of hard and soft tissue is observed nu facial asymmetric subjects and thus soft tissue analysis is needed in addition to hard tissue analysis when making an evaluation of facial asymmetry.

• The korean journal of orthodontics
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• v.37 no.5
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• pp.319-330
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• 2007

Defining right and left side differences in mandibular ramus height is one of the key elements in the diagnosis of facial asymmetry. The purpose of the present study was to evaluate the effect of correction of ramus height with frontal and lateral ramal inclinations (FRI and LRI) in 2-dimensional cephalograms and observe how this affects the diagnostic accuracy of asymmetry. Methods: Frontal and lateral cephalograms were obtained in 40 individuals with chin deviation. FRI and LRI were measured on each side and ramus height measurement was corrected with these inclinations using Pythagorean's theorem. The results of diagnosis before and after correction on cephalograms were compared with the results in 3D CT images. Results: Both FRI and LRI showed greater values in the contralateral side than in the chin-deviated side and these contributed to an increase in the right and left side ramus height differences. After comparison of diagnostic results before and after correction on cephalograms with the results on 3D CT images, the sensitivity increased significantly (from 74 to 94 %) whereas the specificity decreased (from 44 to 22 %). Overall accuracy increased from 68 to 78 % with the correction using FRI and LRI. Conclusions: The results of the present study indicate that correction of ramus height with FRI and LRI is useful for an accurate diagnosis of facial asymmetry on frontal cephalograms.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.4
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• pp.337-345
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• 2011

Purpose: The purpose of this study was to define the relation of the degree of menton deviation and 3-D CT (computerized tomography) measurements of the glenoid fossa and the mandible, which are considered to have an influence on menton deviation. Methods: The CT images were obtained in 60 adults and these were transmitted to a computer and reconstructed using computer software. According to the degree of the menton deviation, which was measured on the posteroanterior cephalogram, the subjects were divided into the menton deviated group (30 adults) and the symmetry group (30 adults). A total of 11 measurements that might have an effect on menton deviation were determined and these were measured in the right and left sides using the function of 3-D measurement in the computer program. The 11 measurements consist of 6 measurements in the glenoid fossa (vertical position of the glenoid fossa and articular eminence, the sagittal position of the glenoid fossa and articular eminence, the depth of the glenoid fossa, and the anterior angle of the glenoid fossa), and 5 measurements in the mandible (ramus length, frontal ramal inclination, lateral ramal inclination, body length, body height). Results: The comparison of the differences between the menton deviated and symmetry groups and correlation analysis on the degree of menton deviation were carried out. The results of comparison of the right and the left difference between the menton deviated and symmetry groups showed that the vertical position and depth of the glenoid fossa were significantly increased in the menton deviated group. Conclusion: The results of the present study show that consideration of the shape and position of the glenoid fossa is necessary for making the diagnosis and administering proper treatment in facial asymmetry patients and especially growing patients.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.3
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• pp.232-240
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• 2008

Purpose: This study was performed to evaluate transverse changes of proximal segment after bilateral sagittal split ramus osteotomy (BSSRO) using 3-D CT in mandibular prognathism. Patients and methods: Twenty-two patients who underwent BSSRO for mandibular set-back in class III malocclusion without facial asymmetry were examined. Miniplates were used for the fixation after BSSRO. Facial CT was taken before and after BSSRO within 3 months. Frontal-ramal inclination (FRI), inter-gonial width (IGW) and intercondylar width (ICW) were measured in 3-D CT images using V-works $4.0^{TM}$ program. Student t-test was used to compare the changes between pre- and post-operative measurements using SPSS 10.0 program. Results: 1. Mean peroperative FRI value ($12.87{\pm}3.43^{\circ}$) was slightly increased to postoperative value ($14.13{\pm}3.72^{\circ}$) (p < 0.05). The average FRI increased 10.42% and the range was from $-2.46^{\circ}$ to $3.34^{\circ}$. 2. Mean peroperative IGW ($99.01{\pm}5.36$) was slightly decreased to postoperative IGW ($96.51{\pm}5.88mm$) (p < 0.05). The average IGW decreased 2.52 % and the range was from $-6.61^{\circ}$ to 0.91 mm. 3. Mean preoperative ICW ($125.01{\pm}5.30mm$) was slightly decreased to postoperative ICW ($125.40{\pm}5.45mm$) (p < 0.05). There is no significant difference between pre- and post-operative ICW. 4. There was significant correlationship between FRI difference and IGW difference (p < 0.05). Conclusions: These results indicate that the lower ramus of the proximal segment is moved inward after BSSRO procedure for mandibular set-back.

• The korean journal of orthodontics
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• v.43 no.4
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• pp.168-177
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• 2013

Objective: In this study, we aimed to examine the relationship between chin deviation and the positional and morphological features of the mandible and to determine the factors that contributed to chin deviation in individuals with a unilateral cleft lip and palate (UCLP). Methods: Cone-beam computed tomography (CBCT) images of 28 adults with UCLP were analyzed in this study. Segmented three-dimensional temporomandibular fossa and mandible images were reconstructed, and angular, linear, and volumetric parameters were measured. Results: For all 28 individuals, the chin was found to deviate to the cleft side by 1.59 mm. Moreover, among these 28 individuals, only 7 showed distinct (more than 4 mm) chin deviation, which was toward the cleft side. Compared to the non-cleft side, the mandibular body length, frontal ramal inclination, and vertical position of the condyle were lower and inclination of the temporomandibular fossa was steeper on the cleft side. Furthermore, the differences in inclination of the temporomandibular fossa, mandibular body length, ramus length, and condylar volume ratio (non-deviated/deviated) were positively correlated with chin deviation. Conclusions: UCLP individuals show mild chin deviation to the cleft side. Statistical differences were noted in the parameters that represented positional and morphological asymmetries of the mandible and temporomandibular fossa; however, these differences were too small to indicate clinical significance.

• The korean journal of orthodontics
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• v.38 no.5
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• pp.314-327
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• 2008

Objective: The purpose of this study was to evaluate the reproducibility of measurements representing asymmetry of the mandible and to identify which landmarks would be more useful in 3-dimensional (3D) CT imaging. Methods: Facial CT images were obtained from forty normal occlusion individuals. Eighteen landmarks were established from the condyle, gonion, and menton areas, and 25 measurements were constructed to represent asymmetry of the mandible; 8 for ramus length, 12 for mandibular body length, 1 for condylar neck length, 2 for frontal ramal inclination, and 2 for lateral ramal inclination. Inter- and intra-examiner reproducibility of the measurements was evaluated. Results: Inter-examiner reproducibility of the measurements proved to be high except for 3 measurements. Intra-examiner reproducibility also proved to be high except for 2 measurements. Inter- and intra-examiner reproducibility of the measurements including Gonion proved to be low. Conclusions: The results of the present study indicate that the landmarks and measurements constructed in 3D CT images can be used for the diagnosis of facial asymmetry.