• The korean journal of orthodontics
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• v.29 no.2 s.73
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• pp.209-217
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• 1999

This study was concerned with comparing the measured values of labial alveolar bone through the lateral cephalometric radiography and mandibular incisor cross-sectional tomogram between two groups, one group of mandibular prognathism patients who needed an orthognathic surgery as an experimental group and the other group who had normal molar relationships as a control group. The purpose of the study was to find out the predisposing factor of bone resorption and gingival recession before orthodontic treatment. The results were as follows: 1. The cross-sectional area of labial alveolar bony plate in mandibular prognathism was significantly smaller than that of control group. 2. In mandibular prognathism, the distance between cementoenamel junction and alveolar crest was significantly greater than control group. 3. There were negative correlations between area of labial alveolar bony plate and distance from cementoenamel junction to alveolar crest, and positive correlations between area of labial alveolar bony plate and distance from alveolar crest to root apex. 4. In mandibular prognathism, there were positive correlations between IMPA and thickness of symphysis, and negative correlations between IMPA and the alveolar bony height. The results of the present study suggest the mandibular prognathism patients are prone to the gingival recession due to the small amount of labial alveolar bone around lower incisors.

• Journal of Yeungnam Medical Science
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• v.9 no.1
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• pp.189-196
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• 1992

Pre-surgical and post-surgical change in adult cleft lip and palate patient following Le Fort I advancement osteotomy combined with bone graft was evaluated clinically and cephalometically. We obtained a successful function and esthetic improvement. The bone graft of alveolo-palatal clefts provides a stable bone support to the adjacent teeth of the cleft area, and well union of adjacent bone tissue, the closure of oronasal fistula and improvement of speech problem. Le Fort I osteotomy following the ostectomy of nasal septum for advancement of the maxilla was obtained relative improvement of esthetics and functional occlusion. 1. The orthodontic correction was required before and after surgery. 2. In this case, there was a limited range of anterior advancement of the Premaxillary-segment due to the scar tissue. 3. After 8 months of operation, we could show the new bone deposition on the cleft site in dental radiograph and then the prosthetic treatement to the missing teeth was done.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.20 no.2
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• pp.299-313
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• 1990

The author analysed tomographic and cephalometric radiographs of 82 temporomandibular joints from 41 symptomatic patients and 40 temporomandibular joints from 20 asymptomatic young adults. The results were as follows; 1. The mean condylar angulation in control group and patient group was 21.72±6.48° 20.13±9.14° respectively and there was no significant difference between two groups. 2. The mean depth of cut was 6.63±0.38㎝ in control group and 6.57±0.46㎝ in patient group. 3. Mean height and width of condylar head were 6.66±1.83㎜, 12.42±0.49㎜ in control group and 6.22±1.36㎜, 11.93±l.92㎜ in patient group. 4. The mean height of articular fossa was 10.20±2.04㎜ in control group and 9.89±1.98㎜ in patient group. The mean width of articular fossa was 21.08±2.08㎜ in control group and 21.24±3.03㎜ in patient group. 5. In centric occlusion the superior joint space was largest (4.15±0.93㎜), followed by the posterior joint space (2.99±0.97㎜) and the anterior joint space (2.70±0.73㎜) in control group. The superior joint space (3.47±1.31㎜) and posterior joint space (3.47±7.07㎜) were same in patient group. There was significant difference in left superior joint spaces between two groups (p<0.05). 6. The condylar position in articular fossa was displaced anteroinferiorly (0.99±3.65㎜ anteriorly, 1.75±1.01㎜ inferiorly) in control group and posteroinferiorly (3.20±4.69㎜ posteriorly, 1.25±1.87㎜ inferiorly) in patient group with 1 inch opening. In maximum opening, it was displaced anteroinferiorly (6.09±3.55㎜ anteriorly, 1.38±2.47㎜ inferiorly) in control group and anteroinferiorly (1.70±5.96㎜ anteriorly, 1.37±1.85㎜ inferiorly) in patient group. There was significant difference in anteroposterior position of both condyles with 1 inch opening and maximum opening between two groups (p<0.01). 7. The mean inclination of upper central incisor and the posterior inclination of articular eminence in control group was 65.60±6.04° 58.88±9.18° in control group, and 67.14±8.41°, 59.70±9.08° in patient group respectively. There was no significant correlation between two groups.

• The korean journal of orthodontics
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• v.30 no.6 s.83
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• pp.669-675
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• 2000

Excessive production of parathyroid hormone causes bony disorder such as periosteal bone resorption and bone pain due to excessive skeletal demineralization. A Class III facial deformity case with generalized root resorption presented bete was fumed out to be due to hyperparathyroidism. Clinical and cephalometric analysis revealed a straight skeletal profile with a retruded maxilla and a prognathic mandible. The x-ray findings demonstrated generalized root resorption of entire dentition to different degree. There also appeared osteoporosis like immature trabecular structure with the evidence of ground glass appearance. Serum test showed elevated 1evel of parathyroid hormone and growth hormone. Change of cranial growth by hyperparathyroidism can be dependent up(In a decreased bone apposition in viscerocranial growth site and abnormalities in cranial suture growth. It is possible to hypothesize that growth retardation of maxilla at least partially be accounted lot hyperparathyroidism. Therefore, regarding to the definite etiology of skeletal Class III and orthodontic treatment planning considering root resorption and osteoporosis, the early diagnosis for the hyperparathyroidism should be carefully carried by clinical and laboratory studies.

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

• The korean journal of orthodontics
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• v.39 no.3
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• pp.136-145
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• 2009

Objective: CBCT has become popular for orthodontic diagnosis and treatment planning in recent times. The 3D pharyngeal airway space needs to be analysed using a 3D diagnostic tool. The aim of this study was to analyse the pharyngeal airway of different craniofacial morphology using CBCT. Methods: The sample compromised 102 subjects divided into 3 groups (Class I, II, III) and 6 subgroups according to normal or vertical craniofacial patterns. All samples had CBCT (VCT, Vatech, Seoul, Korea) taken for orthodontic treatment. The pharyngeal airway was assessed according to the reference planes: aa plane (the most anterior point on the anterior arch of atlas), $CV_2$ plane, and $CV_3$ plane (most infero-anterior point on the body of the second & third cervical vertebra). The intergroup comparison was performed with one-way ANOVA and duncan test as a second step. Results: The results showed the pharyngeal airway and anteroposterior width of group 2 (Class II) in aa plane, $CV_2$ plane, $CV_3$ plane were significant narrower than in group 3 (Class III). There was no significant difference between vertical and normal craniofacial patterns except for the anteroposterior pharyngeal width of Group 1 (Class I) in aa plane. Conclusions: Subjects with Class II patterns have a significantly narrower pharyngeal airway than those with Class III. However there was no difference in pharyngeal airway between vertical and normal craniofacial morphology.

• The korean journal of orthodontics
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• v.26 no.4
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• pp.325-340
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• 1996

Along with traditional goal of 'straightening teeth', today's orthodontics put more and more emphasis on facial esthetics. Naturally, the importance of soft tissue, which dictates one's facial form, is noticed. There have been many cephalometric studies on growth of hard tissue ; however, only a few on that of soft tissue. In Korea, various methods of sampling, measuring and analysing were used to study soft tissue changes, and yet, soft tissue changes along with process of normal growth have not been studied. The author carried out this study as a part of semi-longitudinal study on craniofacial growth and development of Korean children from ages of six to seventeen. 409 boys and 436 girls who'd had no systemic disease for the last three years and shown normal developmental and occlusal status were chosen as subjects. Cephalometric X-rays were taken of each subject, and facial form, lip position & form, nose form, and lip thickness were measured. Mean values and standard deviations were calculated according to age and gender, and figures and tables were drawn accordingly. The following results were obtained: 1. In respect to facial form, boys showed growth for longer period compared to girls. Also, lower face showed higher growth rate than upper face. 2. There was not much change in thickness of upper and lower lips with age; however, they appeared more prominent compared to caucasian children. 3. Nose grew horizontally with age. 4. Horizontal thickness of lower face increased with age, and upper lip thickness at nose base[A-Sn(FH)] showed more growth than anywhere else.

• The korean journal of orthodontics
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• v.35 no.3 s.110
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• pp.182-195
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• 2005

The purpose of this retrospective study was to estimate the pretreatment characteristics of growing patients with Class II malocclusion. who had been treated with maxillary second molar extractions The sample comprised of 51 subjects; 18 subjects were classified into the molar extraction group, and 33 subjects were treated without extraction and classified into the nonextraction group. Pretreatment lateral cephalograms were calculated and analyzed by independent t-test and stepwise discriminant analysis. In measurements for skeletal pattern, no anteroposterior measurements and proportions of various vertical dimensions were significantly different. and only some measurements such as $AB-MP(^{\circ)$, Na-We(mm), AVD (mm) were significantly different between the two treatment groups (p<0.05). In measurements for dentoalveolar pattern. some measurements, which were related to the position and angulation of the upper and lower permanent first molars, and the angulation of the upper third molars, were significantly different between the two treatment groups In particular, the maxillary second molar extraction group exhibited more mesial angulation of maxillary first molar to the occlusal plane.

• The korean journal of orthodontics
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• v.27 no.1
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• pp.65-78
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• 1997

This study was carried out in order to determine soft tissue response to incisor movement and mandibular repositioning and to determine feasibility of predicting vertical and horizontal changes in soft tissue with hard tissue movement. For this study, cephalometric records of 41 orthodontically treated adult females who had Angle's Class II division 1 malocclusion were selected and stepwise multiple regression analysis was employed. Following conclusions were obtained by analysing the changes of soft tissue and hard tissue before and after treatment. 1. Hard tissue measurements that showed significant changes before and after treatment were horizontal and angular changes of maxillary incisor, horizontal,vertical and angular changes of mandibular incisor, overjet, overbite, interincisal angle, mandibular repositioning, A,B, skeletal convexity and soft tissue measurements that showed significant changes were horizontal, thickness and angular changes of upper lip, horizontal and angular changes of lower lip, interlabial angle, nasolabial angle labiomental angle, Sri, Ss, Si and soft tissue convexity(P<0.05). 2. All Soft tissue measurements changed significantly before and after treatment had between one and four hard tissue independent variables at statistically significant level, indicating that all soft tissue changes were direct relationship with hard tissue changes 3. Ova jet, horizontal change of maxillary incisor, horizontal change of maxillary root apex and horizontal change of pogonion entered into prediction equations most frequentely indicating that they were more significant variables in prediction of vertical and horizontal changes in the soft tissue with treatment, but vertical changes of mandibular incisor not entered any prediction equations, indicating that it was not considered a good predictor for soft tissue changes with maxillary incisor retraction. 4. Horizontal and vertical changes in subnasale were found to have most independent variables, significant at the 0.05 level in prediction-equations(${\Delta}$Sn(H):Ur, Is(H), Pg(H), UIA,${\Delta}$Sn(V): Is(H), Pg(H), overjet, A), indicating that subnasale changes are influenced by complex hard tissue interaction. 5. Multiple correlation coefficient($R^2$) of the soft tissue prediction equations ranges from 0.2-0.6.

• Journal of Oral Medicine and Pain
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• v.32 no.3
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• pp.293-303
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• 2007

The purpose of this paper is to evaluate if there is a relationship between anterior disc displacement without reduction and development of anterior open bite, and a relation between occurrence of open bite and occlusal appliance therapy. In general, the statistically significant differences were found between the Group 1 and 2 and normal mean group. The variables that represent mandibular size and form, showed a statistical significance in all 3 groups. Also 3 groups patients had a smaller ANB, a larger FMA than normal mean group. When we compared the 3 groups with respect to all cephalometric measurements by One-way analysis of variance (ANOVA), group 1 and 2 patients had a larger FMA, a larger SN to mandibular plane angle, a larger maxillomandibular plane angle, a larger occlusal plane to mandibular plane angle, a smaller total posterior facial height/total anterior facial height(%), and a larger gonial angle than group 3. The statistically significant differences were not found between the Group 1 and 2, and skeletal patterns were similar. Thus, morphologic features of patients with vertical discrepancies may represent a risk factor for the development of anterior open bite with or without occlusal appliance treatment. In case of patients with vertical discrepancy, we may have to be more careful when inducing a change of the vertical dimension.