• The korean journal of orthodontics
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• v.25 no.5 s.52
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• pp.613-625
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• 1995

The purpose of this study was to investigate the degree of relapse following orthognathic surgery and the relationship between preoperative state and the methods of orthognathic surgery in skeletal Class III patients. Thirty-one patients were selected(17 men, and 14 women) for this study, who had received orthognathic surgery(20 one jaw surgery, and 11 two jaw surgery). The mean age was 22.5 years. Their lateral cephalograms, that were taken preoperatively, immediate postoperatively and follow-up over one year, were traced and analysed. The results were as follows : 1. In two jaw surgery, mandibular length, lower facial height and lower lip length were 4.24mm, 4.64mm and 4.13mm longer than in one jaw surgery, respectively But in two jaw surgery, overjet was 3.13mm shorter than in one jaw surgery. 2. In one jaw surgery, mandible was moved back $8.95\pm4.45mm$ at B point. In two jaw surgery, maxilla was moved forward $5.15\pm3.46mm$ and mandible was moved back $7.24\pm9.11mm$ at B point. 3. Between postoperation and follow-up over one year, A point, A' point, Pn and Sn were moved backward 1.02 $\pm$ 2.14mm, $1.73\pm1.63mm,\;1.05\pm1.48mm\;and\;1.55\pm1.37mm$ in two jaw surgery, respectively. 4. Between postoperation and follow-up over one year, in one jaw surgery, B point was moved forward $2.58\pm4.22mm$ and B' point was moved forward $1.95\pm4.39mm$. In two jaw surgery, B point was moved forward $0.65\pm2.88mm$ and B' point was moved forward $0.19\pm3.32mm$. In one jaw surgery, relapse rate was $28\%$ at B point and $24\%$ at B' point, whereas in two jaw surgery, relapse rate was $8\%$ at B point and $3\%$ at B' point.

• The korean journal of orthodontics
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• v.28 no.3 s.68
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• pp.461-477
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• 1998

To evaluate the relapse pattern and long-term stabilities depanding on surgical methods following orthognathic surgery of Cl III patients, the author selected 24 subjects(10 male, 14 female) operated by SSRO and 26 subjects(10 male,16 female) operated by IVRO. Each subject took four lateral cephalograms : just before surgery(T1), within 48hrs after surgery(T2), 4-8 wks after surgery(T3), 6 month or more after surgery(T4), and the landmarks were digitized. The differences of relapse patterns in each interval between two groups were compared and the significance of correlation among the variables of each group was tested. The obtained results are as follows ; 1. Horizontal early relapse was forward movement of mandible in SSRO group, as compared to the backward movement in IVRO group, and there was a statistical significance between the two groups. 2. Vertical early and late relapses were decreases in anterior facial height in both groups and there was no statistical significance between the two groups. 3. There was a statistical significance in negative correlation between mandibular horizontal late relapse and surgical change of articular angle in SSRO group. 4. There was a statistical significance in negative correlation between amount of mandibular set-back and mandibular horizontal early relapse in both groups.

• The korean journal of orthodontics
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• v.30 no.3 s.80
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• pp.343-355
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• 2000

The purpose of this study was to evaluate the amount and interrelationship of hard and soft tissue changes after mandibular setback osteotomy and reduction genioplasty in mandibular prognathism with long anterior facial height. The control group (Group A) consisted of 20 patients who had severe horizontal discrepancy. They experienced Presurgical orthodontic treatment and orthognathic surgery via mandibular setback. The experimental group (Group B) consisted of 20 patients who had severe horizontal and vertical discrepancy. They experienced presurgical orthodontic treatment and orthognathic surgery via mandibular setback and reduction genioplasty. The presurgical and postsurgical lateral cephalograms were evaluated. The computerized statistical analysis was tarried on with EXCEL 97 program. The results were as follows : 1. The correlation of hard and soft tissue horizontal changes in lower 2/3 of lower anterior facial height were high for both groups. The correlation coefficients of hard tissue changes and Ls, Stm, Li changes in Group B were moderately higher than Group A. 2. The correlation of hard and soft tissue vortical changes in Group B were lower than Group A. (except for pointB-Ils, Me-Me') 3. The ratio for soft tissue to Pog in Group B was lower than Group A. The ratios of hard and soft tissue vertical changes were 32% at Ils, 54% at Pog', and 60% at Me'. 4. The ratio of lower anterior facial height to total anterior facial height was reduced for both groups. But ratio of upper 1/3 of lower anterior facial height to total anterior facial height did not changed significantly in Group B. 5. Reduction genioplasty combined with mandibular setback procedure showed no change in upper one third(Sn-Stm) and significant decrease(Stm-Me') in the lower two thirds of the soft-tissue anterior lower facial height

• The korean journal of orthodontics
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• v.26 no.1 s.54
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• pp.1-16
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• 1996

The purpose of this study was to evaluate the amount and interrelationship of the soft and hard tissue changes after simultaneous maxillary advancement and mandibular setback surgery in skeletal Class III malocclusion. The sample consisted of 25 adult patients(13 males and 12 females) who had severe anteroposterior skeletal discrepancy. These patients had received presurgical orthodontic treatment and surgical treatment which consisted of simultaneous Le Fort I or Le Fort II osteotomy and bilateral sagittal split ramus osteotomy. The presurgical and postsurgical lateral cephalograms were evaluated. The computerized statistical analysis was carried out with SPSS/$PC^+$ program. The results were as follows. 1. The correlation of maxillary hard and soft tissue horizontal changes were high and the ratios for soft tissue to A point were $71\%$ at Sn, $67\%$ at SLS and $37\%$ at LS. 2. The correlation of mandibular hard and soft tissue horizontal changes were very high and the ratios were $84\%$ at LI, $107\%$ at ILS, $96\%$ at Pog' and $97\%$ at Gn'. 3. The correlation of mandibular hard tissue horizontal changes and soft tissue vertical changes were moderate. 4. The upper to lower lip length were increased(P<0.001). 5. The soft tissue thickness were decreased in upper lip and increased in lower lip(P<0.001). The postsurgical changes were reversely correlated with initial thickness in upper lip.

• The korean journal of orthodontics
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• v.33 no.3 s.98
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• pp.211-222
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• 2003

The purpose of this study was to determine whether there is an association between disk displacement of the Temporomandibular Joint (TMJ) and dentofacial asymmetry In orthodontic patients. The subjects consisted of 60 female orthodontic patients between the ages of 18 and 38 years (mean age 23.3 years) who had visited the Department of Orthodontics at Seoul National University Dental Hospital from January 2000 to April 2002. On the basis of magnetic resonance imaging (MRI) of their bilateral TMJs, the subjects were divided Into four groups'. bilateral normal group (twenty-one persons); disk displacement of right TMJ group (six persons); disk displacement of left TMJ group (nine persons); and disk displacement of both TMJs group (twenty-four persons) Postero-anterior (PA) cephalograms and diagnostic models which had been taken before orthodontic treatment were measured. In the linear measurements, a line connecting the right and left Latero-Orbitale (Lo) represented the horizontal reference line (H). The vertical reference line (V) was constructed as a line bisecting and running perpendicular to H. One-way analysis of variance (ANOVA) was used to test whether the mean values of measurements between groups were significantly different. In addition, Bonferronil's multiple comparison test was performed at a level of 0.05. The results were as follows; 1 In the diagnostic model analysis, the overjet, nght molar relationship, and left molar relationship were significantly different among the four groups. 2. In the PA cephalometric analysis, differences in the right and left vertical position of the lower first molar and Ag were significantly dissimilar among the four groups. 3. If the disk displacement of TMJ was present on one side, the ipsilateral ramus was shorter, resulting in asymmetry in the vertical position of Ag. This study indicated that dentofacial asymmetry might be related to the disk displacement of TMJ.

• The korean journal of orthodontics
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• v.39 no.6
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• pp.362-371
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• 2009

Objective: The purpose of this study was to compare the longitudinal treatment effects of facemask with rapid maxillary expansion (FM/RME) and chincup (CC) therapy followed by fixed orthodontic treatment (FOT) in Class III malocclusion (CIII) patients. Methods: The samples consisted of twenty-one CIII patients who had similar skeletal and dental characteristics before FM/RME or CC therapy and good retention results (Class I molar/canine relationship and positive overbite/overjet) after FOT (Group 1, FM/RME, n = 11; Group 2, CC, n = 10). Lateral cephalograms were taken before (T0) and after FM/RME or CC therapy (T1), and after FOT and retention (T2). Skeletal and dental variables were measured. Mann-Whitney U-test and Wilcoxon signed-rank test were used for statistical analysis. Results: During T0-T1, FM/RME therapy induced forward movement of point A, and labioversion of the upper incisors. Both groups showed posterior repositioning of the mandible. FM/RME resulted in increase of the vertical dimension; however, CC caused an increase in articular angle and decrease in gonial angle. During T1-T2, both groups exhibited forward growth of point A. Group 1 showed forward growth and counterclockwise rotation of the mandible and increase of IMPA; however, Group 2, showed increase of ANS-Me/N-Me and decrease of overbite. Conclusions: The key factor for successful FM/RME and CC therapy and good retention results might be a harmonized forward growth of the maxilla that could keep pace with the growth and rotation of the mandible.

• The korean journal of orthodontics
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• v.26 no.2 s.55
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• pp.205-218
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• 1996

A given facial type can be considered as a syndrome in which various features are aggregated, so a single parameter is not sufficient to accurately identify a given facial type. This study was designed to identify & characterize the skeletal types that blend under the headline-'Cl III,deepbite'. Cephalograms of thirty-four untreated mixed dentition patients, selected mainly on the basis of clinical impression of Cl III with reduced lower face heights were studied. The following conclusion can be drawn. 1. Cl III malocclusion with reduced lower face height could be classified into three types. 2. Subtype 1 was identified by the following features : strong ramus, more anteriorly positioned upper molars without alveolar hypoplasia, acutely reduced Mn. plane angle. 3. Subtype 2 was characterized by a short ramus, sharply reduced postrior alveolar height, and normal Mn. plane angle. In general, this type had hypoplasia tendency in the vertical dimension. 4. In subtype 3, the AUFH occupying more percentage than ALFH was a outstanding feature. Ramal height was in normal range, alveolar hypoplasia and slightly reduced Mn. plane angle was observed. 5. The features of the subtypes were reflected in certain indices, which can be regarded as discriminative index. LAFH: if reduced, regardless of subtypes, indicates reduced lower ant. face height consistently. FHR: when this ratio is increased, it indicates subtype 1. FHI: when this ratio is in normal range, it indicates subtype 2. FPI: if reduced greatly, it indicates subtype 3.

• The korean journal of orthodontics
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• v.27 no.4 s.63
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• pp.643-659
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• 1997

For the total treatment of skeletal malocclusions, 3-dimensional evaluation and diagnosis are essential. Although anteroposterior discrepancies can be evaluated through various methods, the satisfactory methods for evaluations of facial asymmetry and transverse discrepancies are yet to be found. The adequate diagnosis and treatment of transverse discrepancies may be more important in the maintenance of functional occlusion as well as for the stability of results obtained from orthognathic surgery than the anteroposterior or vertical discrepancies. Since the soft tissue effects from the transverse discrepancies may not be pronounced, especially when combined with anteroposterior or vertical discrepancies which have prominent characteristics, the differentiation of their effects may be difficult from visual inspection alone. Therefore it is essential that the normal facial proportions would be established from the posteroanterior cephalometry as a reference for the accurate diagnosis and treatment. The present study evaluates 76 subjects from Yonsei University freshmen with normal facial symmetry and occlusion. Posteroanterior cephalograms were taken from the subjects and the normal values and facial proportions are obtained. The results are as follows. 1. The transverse and vortical values from posteroanterior cephalometry and their ratio, with means and standard deviations are calculated. 2. The ratio of vertical values to transverse values is 0.837 (male 0.836, female 0.841). 3. The Proportion of maxillary and mandibular widths is 0.747 (male 0.745, female 0.752), with statistically significant correlation. 4. Various degree of significant correlations are observed in the following craniofacial widths; (Cranial width, Bizygomaticofrontal suture width, Facial width, Maxillary width, Upper & Lower Intermolar width, Mandibular width). 5. Although the facial height as well as other line measurements increase as the facial widths increase, angle measurement ($Bj\ddot{o}rk$ Sum, Mandibular Plane Angle, Gonial Angle), decreases and posterior to anterior facial height ratio increases, therefore indicating the tendency for a brachycephalic facial type. These results may be used as references for the treatment planning in orthognathic and orthodontic treatments for the dentofacial deformity patients.

• The korean journal of orthodontics
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• v.38 no.1
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• pp.52-59
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• 2008

Objective: This study analyzed the morphologic changes of the fourth cervical vertebra body to determine the skeletal age of orthodontic patients during growth. Methods: Eighty-one female patients aged from 11 to 14 who had cephalograms taken on the same day were examined. The subjects were divided into three groups depending on the depth of the concavity of the lower border of the fourth cervical vertebra (Group A: less than 1.05 mm, Group B: 1.05 - 2.07 mm, Group C: greater than 2.07 mm). Menarcheal timing, SMI stage, length, width and ratio of length and width of the fourth cervical vertebra body were analyzed and the following results were obtained. Results: The average SMI stage of group A, B and C were $5.67{\pm}2.57,\;8.73{\pm}2.41,\;and\;10.00{\pm}1.47$, respectively. Length, width, ratio of length and width, and SMI stage were greater in group B than group A and in group C than group B. Mean menarcheal timing was $11.64{\pm}0.92$ years. Concavity depth, length, width, ratio of length and width showed a significant positive correlation with SMI stage, especially with the concavity depth. Conclusion: The results of this study propose a simple method for determining the timing of orthopedic treatment by measuring the concavity depth of the fourth cervical vertebra on the cephalogram.

• The korean journal of orthodontics
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• v.39 no.3
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• pp.168-176
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• 2009

Objective: The purpose of this study was to evaluate how airway changes influence facial growth during puberty in Korean children. Methods: Thirty-six patients aged 9 to 11 (mean age: 10.7 years) were selected. Cephalograms and hand-wrist x-rays were taken at pre-treatment (T1) and post-treatment (T2). The sample was divided into narrow (5.2 - 8.6 mm, AW-Narrow), medium (8.9 - 11.5 mm, AW-Medium), and wide (11.7 - 16.0 mm, AW-Wide) groups according to the airway width at T1. Cephalometric measurements at T1, T2 and growth from T1 to T2 were compared between groups. Results: The degree of increase in airway size in each group was 4.55 mm, 3.84 mm and 1.94 mm in the AW-Narrow, AW-Medium, and AW-Wide groups, respectively. Moreover, the differences were statistically significant. The significant smallest posterior facial height was found in the AW-Narrow group at T1. For the growth values from T1 to T2, the AW-Narrow group showed significantly larger values of PFH/AFH, facial axis, ANS (T1 - T2), and Gn (T1 - T2) than the AW-Medium group. Conclusions: The compensational changes in the airway width and facial growth were found in the narrow group. Surgical approach of the airway to prevent unfavorable facial growth in these years of age should be carried out, but with careful deliberation because these problems may be improved naturally.