• The Journal of the Korea Contents Association
• /
• v.9 no.11
• /
• pp.254-261
• /
• 2009

This study suggested that the table of CT-simulator and the laser alignment system using diagnostic CT scanner have an efficient method for improvement in alignment between the planned target center of traverse image with CT scanner. It was conducted on the daily QA when presented in the AAPM TG66 with correcting the laser alignment system using geometric trigonometric functions and investigated the effectiveness of correction methods as compared with those before and after correction. Before correction error was 3.82mm between the planned target center of image, the table longitudinal axis was twisted with 0.436o. The laser alignment system using geometric trigonometric functions in after correction was satisfied with tolerance limits of ${\pm}2mm$ when occurred about 0.7mm in errors between the planned target center. The table correction to satisfy the geometric accuracy is very inefficient over against the time and economic loss as well as technical limits in the case of application as only radiation therapy associated with CT-simulator with diagnostic CT scanner in use. But, the method which corrects the laser alignment system is economic and relatively simple with possibility of getting well geometric accuracy and we suppose that it is efficient method for applying in the clinic.

• The korean journal of orthodontics
• /
• v.30 no.1 s.78
• /
• pp.1-7
• /
• 2000

It is important that the orthodontist accurately assess the degree to which facial asymmetry contributes to a given malocclusion before treatment planning. P-A, submentovertex and verticosubmental view have been used in the assessment of facial asymmetry. Among them, submentovertex view is rarely used because it has low reproducibility and is short of normal data and proper analysis method. The purpose of this study was to develop a submentovertex cephalomentrics and obtain normal data in Korean adults. The subjects consisted of 40 normal adults (male : 22, female 18) without the experience of orthodontic treatment. We find the 2 angular and 9 linear measurements. Though submentovertex cephalomentrics has the limitation in comparing the absolute length between right and left, it is useful to examine the relationship of skeletal and dental midline, the shape and location of condyle head and the shape of mandibular body in submentovertex view Therefore, if we understand the limitation of submentovertex cephalomentrics and use lateral , P-A and submentovertex cephalomentrics together, we will measure the location and amount of skeletal disharmony more exactly.

• The korean journal of orthodontics
• /
• v.33 no.3 s.98
• /
• pp.141-150
• /
• 2003

The purposes of this study were to classify the anteroposterior and vertical skeletal pattern of normal occlusion samples into specific types with factor and hierarchical cluster analysis, and to evaluate the range and limit of skeletal relationships that permit the establishment of normal occlusion via natural dentoalveolar compensation. Lateral cephalograms of 294 normal occlusion samples were measured, as selected from 15,836 persons through a community dental health survey who cooperated in record taking. Using a factor analysis, two factors representing anteroposterior and vertical skeletal relationships were extracted from 18 skeletal measurements. Then cluster analysis classified the skeletal patterns into nine types. The means and the standard deviations of 8 anteroposterior skeletal measurements and 10 vertical skeletal measurements were determined and comparisons of these measurements among the types were performed. The results obtained in this study showed that the range of normal occlusion included very diverse anteroposterior and vertical skeletal relationships.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.46 no.4
• /
• pp.422-432
• /
• 2019

Treatment options for impacted permanent molars include orthodontic traction, surgical repositioning, transplantation, and extraction of the impacted teeth. Orthodontic traction is recommended because it is the most conservative method. However, it has limitations, such as loss of tooth anchorage. In an effort to overcome these limitations, skeletal anchorage devices tailored for orthodontic use were developed. In this case report, 3 patients were diagnosed with impacted permanent molars. The impacted teeth of these patients were surgically exposed, the orthodontic devices were attached, and the skeletal anchorage devices were implanted for the successful traction of the impacted teeth.

• The korean journal of orthodontics
• /
• v.31 no.1 s.84
• /
• pp.97-105
• /
• 2001

In many cases of orthodontic treatment the upper anterior teeth are retracted. Periodontal problems may arise during incisor retraction, if the amount of tooth movement and the amount of remodeling in the anterior cortical bone are not the same. Therefore in this study, to find out the relationship between the amount of tooth movement and the amount of bone remodeling during retraction of the upper anterior teeth, lateral cephalograms of 56 female patients over 18-year-old were taken before and after treatment. Among the 56 patients, two groups were divided according to the type of root movement during retraction. 26 patients mainly moved by tipping and 30 by bodily movement. The cephalograms taken before and after treatment were superimposed upon the true horizontal plane. In the Tip-Group, the horizontal bone remodeling/tooth movement ratio was 1:1.63, and in the Torque-Group it was 1:1.66. Because the amount of tooth movement and the amount of bone remodeling were not the same in both groups, in the Tip-Group the root apex moved away from the palatal cortical plate and closer to the labial cortical plate, whereas in the Torque-Group the root moved away from the labial cortical plate and closet to the palatal cortical plate. Therefore, there are limitations in the amount of incisor retraction in patients with a very thin anterior cortical plate in the maxilla, and in patients with severe skeletal discrepancies orthognathic surgery should be considered and when orthodontic camouflage treatment is the only possible method, the orthodontist must be aware of the limitations of treatment.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.37 no.4
• /
• pp.537-544
• /
• 2010

Anchorage control in orthodontic treatment is an important factor affecting treatment results. In the conventional approach, intra-oral anchorage such as application of differential force and moment, Nance holding arch and lingual arch, as well as extra-oral anchorage such as head gear were used for anchorage reinforcement. However, these anchorages may result in undesired tooth movement and require patient cooperation. To overcome these disadvantages, skeletal anchorage system was introduced as orthodontic anchorage. Types of skeletal anchorage include implant, onplant, miniplate and miniscrew. Especially, miniscrew has many advantages such as reduced patient cooperation, low cost and easy placement. Recently, it is successfully used in orthodontic treatment. This cases were treated using orthodontic miniscrews for retraction of ectopically erupting maxillary canine and impacted mandibular canine and intrusion of maxillary incisors.

• The korean journal of orthodontics
• /
• v.29 no.2 s.73
• /
• pp.147-156
• /
• 1999

Skeletal Cl III malocclusion is an orthopedic appliance mainly used for growing children with maxillary undergrowth, which largely entails skeletal Cl III malocclusion. It improves anterior crossbite and maxillary position and thus, enables patients to attain favorable Profile but often involves unfavorable profile with protrusive upper and lower lips. Therefore, if orthodontists have knowledge of which condition helps obtain favorable occlusion and profile, they are able to predict the prognosis and limitation of the treatment. This study was done in order to help obtain favorable Profile after treating growing skeletal Cl III children. In the study, we classified childern into two groups, the one with favorable profile(Group 1, n=12) and the other with unfavorable profile(Group 2, n=14) and, with retrospective study using pre- and post-treatment lateral cephalogram, drew the following conclusions. 1. As patients had more serious labioversion of upper incisors, they were more unlikely to have favorable profiles after the treatment. Protrusion of prosthion, which was related with maxillary incisors, also affected profiles. 2. As the NL-ML angle before the treatment was small, it was more likely to get favorable profile. 3. As the degree of lower lip protrusion was high, it was likely to have bialveolar protrusion after the treatment. 4. As the degree of downward and backward rotation of mandible was high, it was likely to get unfavorable profile.

• The korean journal of orthodontics
• /
• v.30 no.3 s.80
• /
• pp.355-365
• /
• 2000

The treatment plan for orthognathic surgery must be based on accurate predictions, and this can be produced the most esthetic results. Treatment of prognathic mandible in adult is usually orthognathic surgery using mandible set back, but mandible with retruded chin point is needed additional chin augmentation. In this case, the directions between mandible and chin point are different therefore, the prediction of soft tissue reactions must be modified. In this study, we materialize the patients who was taken orthognathic surgery due to prognathic mandible, 11each(Group A) was taken only Bilateral Sagittal Sprit Ramus Osteotomy (BSSRO), 9each(Group B) was taken additional advancement genioplasty. The lateral cephalometric radiography taken 8 months later after orthognathic surgery by this patients were used. The results of this study were as follows : 1. The profile of lips was favorable after surgery due to upper lip to I-line became prominent and lower lip tc E-line was retruded. 2. In both group, upper lip moved posteriorly and nasolabial angle was increased. 3. The ratio of the soft tissue profile change in POGs point to skeletal B point movement was $84\%$ in group A and $66\%$ in group B, and there was statistical significance between group A and group B. 4. Vertical movement of hard tissue points is decreased in group A.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.29 no.1
• /
• pp.95-101
• /
• 2013

Recently, the demand for esthetic improvement by a treatment neither time consuming nor invasive is increasing. The patient wanted the maxillary anterior teeth appearance to be improved by prosthetic treatment, not other treatments such as orthodontic, periodontal, and endodontic treatments, despite the limit of esthetic improvement. In this case, among the recent variety of all ceramic systems for the aesthetic prosthetic restoration, we selected the zirconia-based system as a method of restoration in order to conceal the discoloration of teeth. The patient was satisfied with the esthetic results.

• The korean journal of orthodontics
• /
• v.38 no.1
• /
• pp.41-51
• /
• 2008

Objective: The aim of this study was to compare the initial lateral cephalometric characteristics in two groups of patients: those that had mandibular setback surgery only and those that had mandibular setback surgery with advancement genioplasty. Methods: The lateral cephalograms of thirty-one patients were studied. Twenty-one Class III patients (group A) had only madibular setback surgery Twelve Class III patients (group B) had mandibular setback surgery with advancement genioplasty. Results: Differences between two groups were found in N-Me, ANS-Me, Occlusal Plane angle, Palatal Plane to U1, Mandibular Plane to L1, Mandibular Plane to L6, SN to U1, Sn-Stms, and Pog' projection. Compared to group A, group B showed more linguoversion and extrusion of upper incisors, more extrusion of lower incisors and lower first molar, and more steepness of the occlusal plane. N-Me, ANS-Me, and Sn-Stms were also longer in group B. But Pog' projection was shorter than group A. Conclusion: We conclude that certain initial lateral cephalometric characteristics may help indicate the inclusion of advancement genioplasty when mandibular setback surgery is planned in skeletal Class III patients.