• The korean journal of orthodontics
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• v.24 no.3 s.46
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• pp.695-707
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• 1994

This study investigates the effects of third molar on the occlusal plane in Angle's class El malocclusion with possibilities of posterior crowding and the interrelationships of occlusal plane inclinations to other skeletal patterns. Above investigations might showed that considerations should be given to third molars with possibilities of posterior crowding in establishing diagnosis and treatment plans for Angle's class III malocclusion patients. The following conclusions were obtained 1. In events of third molars causing possible posterior crowding, maxillary third molars showed more mesial inclinations than second molars, and compared to those with third molar missing cases, first molars were more mesially inclined and displaced more inferiorly from the palatal plane and OP-MP was increase , thus the occlusal plane was less steep. 2. In events of third molars causing possible posterior crowding, the anglulation between AB line and mandibular plane was decreased and ANB showed negative values. Thus chin points were more protruded, ramus were more anteriorly displaced, and increase in lower facial height, genial angle, effective mandibular length and mandibular plane angle were observed. This in all caused more vertical opening and more severe skeletal disturbance. 3. OP-MP was increased as the maxillary first molars were more inferiorly displaced from the palatal plane. As this angle was increased mandibular planes were more inferiorly inclined and LFH, genial angle, effective mandibular length were more increased and mandibular ramus was more anteriorly placed. 4. As the maxillary first molars were more inferiorly placed from the palatal plane, more increased OP-MP/PP-MP ratio made the occlusal plane less steep. As OP-MP/PP-MP was increased, mandibular ramus was more anteriorly placed and made longer, and facial angle and effective mandibular length were increased.

• Imaging Science in Dentistry
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• v.50 no.1
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• pp.9-14
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• 2020

Purpose: The purpose of this study was to evaluate vertical bone loss and alveolar bone thickness in the maxillary and mandibular incisors of patients with skeletal class III malocclusion. This study also aimed to evaluate the periodontal condition of class III malocclusion patients who had not undergone orthodontic treatment. Materials and Methods: The sample included cone-beam computed tomography scans of 24 Korean subjects (3 male and 21 female). Alveolar bone thickness (ABT), alveolar bone area (ABA), alveolar bone loss (ABL), and fenestration of the maxillary and mandibular incisors were measured using 3-dimensional imaging software. Results: All incisors displayed an ABT of less than 1.0 mm from the labial surface to root level 7 (70% of the root length). A statistically significant difference was observed between the mandibular labial and lingual ABAs and between the maxillary labial and mandibular labial ABAs. The lingual ABA of the mandibular lateral incisors was larger than that of the mandibular central incisors. ABL was severe on the labial surface. A statistically significant difference was observed between the maxillary and mandibular labial ABL values(21.8% and 34.4%, respectively). Mandibular lingual ABL (27.6%) was significantly more severe than maxillary lingual ABL (18.3%) (P<0.05). Eighty-two fenestrations were found on the labial surfaces of the incisors, while only 2 fenestrations were observed on the lingual surfaces. Fenestrations were most commonly observed at root level 6. Conclusion: Careful evaluation is needed before orthodontic treatment to avoid iatrogenic damage of periodontal support when treating patients with class III malocclusion.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.38 no.3
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• pp.139-144
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• 2012

This study was performed in order to evaluate the occurrence of temporomandibular joint disorder after surgical correction of skeletal class II malocclusion. Materials and Methods: This study included 21 patients who underwent orthognathic surgery for the correction of dentofacial deformities by a single surgeon at Mokdong Hospital, Ewha Womans University from 2000 to 2010. They underwent bilateral sagittal split ramus osteotomy for the treatment of undesirable mandibular advancement. The temporomandibular disorder (TMD) symptoms prior to surgery were recorded and the radiographic evaluation (panorama, bone scan, and magnetic resonance imaging [MRI]) of the post-surgery temporomandibular joint (TMJ) were assessed in order to evaluate condylar resorption, remodeling and disc displacement. The minimum follow-up period, including orthodontic treatment, was 12 months. Orthognathic procedures included 1-jaw surgery (n=8 patients) and 2-jaw surgery (n=13 patients). The monocortical plate was used for bilateral sagittal split ramus osteotomy fixation. Results: Among class II malocclusion patients with TMD symptom, clicking improved in 29.1%, and maximum mouth opening increased from $34.5{\pm}2.1$ mm to $37.2{\pm}3.5$ mm. The differences were not statistically significant, however. Radiographic changes in bone scan improved slightly based on the report by radiologist but not in TMJ dynamic MRI. Conclusion: No particular improvements were found in patients with joint sound only. Patients with limitation of mouth opening showed an increase in the degree of opening, but the difference was not statistically significant (P>0.05).

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.4
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• pp.479-484
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• 2000

The conventional treatment of skeletal class III malocclusion has been focused on the application of orthopedic forrce primarily to the mandible. Thus moderate Class III malocclusions can be corrected by the anterior displacement of the maxilla and maxillary dentition, possibly by restricting the growth of the mandible or by changing its direction. The patients having skeletal Class III malocclusion were treated with removable appliance & fixed appliance for detailed tooth movement and the following results were observed: 1. The anterior crossbite was corrected. 2. The forward and downward growth of the maxillary complex was obtained. 3. The lingual tipping of the mandiblar incisors was performed and the mandible was rotated in the clockwise direction.

• The korean journal of orthodontics
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• v.29 no.2 s.73
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• pp.251-265
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• 1999

Various types of horizontal reference planes are used for diagnosis, treatment planning and evaluation of treatment results. But these reference Planes lack accuracy and repro-ducibility, and are mainly for Caucasian. Unlike the adult patients who have completed growth, the horizontal reference planes for growing children may change continuously during growth. Therefore this must be considered in selecting the horizontal reference plane. The purpose of this study was to Investigate the angle formed by the Sella-Nasion(SN) plane and Frankfort-Horizontal(FH) plane and evaluate the angle formed by FH plane and other horizontal reference planes in relation to different skeletal maturity and malocclusion types. 540 subjects with no orthodontic treatment history were chosen, and hand -wrist X-rays and lateral cephalometric X-rays were taken. According to SMA(Skeletal Maturity Assessment) of hand-wrist X-rays, the subjects were classified into 3 skeletal maturity groups : SMI 1-4 for group A, SMI 5-7 for group B and SMI 8-11 for group C. A second classification was made according to cephalometric analysis of lateral cephalograms. The subjects were classified into 3 malocclusion groups : Skeletal Class I, II and III malocclusion group. 10 measurements were evaluated. The results were as follows. 1. The angle formed by the SN plane and FH plane showed no difference among skeletal maturity groups, malocclusion groups, and between .sexes. 2. The angles formed by the SN plane and FH plane were $8.27^{\circ}{\pm}2.31^{\circ}$ for males and $8.59^{\circ}{\pm}2.24^{\circ}$ for females. The average value for females and males was $8.42^{\circ}{\pm}2.28^{\circ}$. 3. The angle formed by the FH plane and palatal plane was almost constant showing no difference among skeletal maturity groups, malocclusion groups, and between sexes($1.09^{\circ}{\pm}3.21^{\circ}$).

• Imaging Science in Dentistry
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• v.47 no.1
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• pp.1-9
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• 2017

Purpose: This retrospective study aimed to evaluate the nasopharyngeal and oropharyngeal dimensions of individuals with skeletal class II, division 1 and division 2 patterns during the pre-peak, peak, and post-peak growth periods for comparison with a skeletal class I control group. Materials and Methods: Totally 124 lateral cephalograms (47 for skeletal class I; 45 for skeletal class II, division 1; and 32 for skeletal class II, division 2) in pre-peak, peak, and post-peak growth periods were selected from the department archives. Thirteen landmarks, 4 angular and 4 linear measurements, and 4 proportional calculations were obtained. The ANOVA and Duncan test were applied to compare the differences among the study groups during the growth periods. Results: Statistically significant differences were found between the skeletal class II, division 2 group and other groups for the gonion-gnathion/sella-nasion angle. The sella-nasion-B-point angle was different among the groups, while the A-point-nasion-B-point angle was significantly different for all 3 groups. The nasopharyngeal airway space showed a statistically significant difference among the groups throughout the growth periods. The interaction among the growth periods and study groups was statistically significant regarding the upper oropharyngeal airway space measurement. The lower oropharyngeal airway space measurement showed a statistically significant difference among the groups, with the smallest dimension observed in the skeletal class II, division 2 group. Conclusion: The naso-oropharyngeal airway dimensions showed a statistically significant difference among the class II, division 1; class II, division 2; and class I groups during different growth periods.

• The korean journal of orthodontics
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• v.32 no.3 s.92
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• pp.209-225
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• 2002

Enlow's counterpart analysis reflects the characteristics of each individual sample to find out the cause of the malocclusion and further applying them to the clinic. Enlow's counterpart analysis was performed on 100 Korean samples (50 male, 50 female) with normal occlusion and 100 skeletal class III patients (50 male, 50 female) scheduled for orthognathic surgery. The following conclusions were obtained. 1. The cause of malocclusion in skeletal class III patients were complex and interrelated : backward upward rotation of the cranial base, forward inclination of the ramus, increase in the mandibular body length, and posteriorly located maxilla. 2. Seen on R2 (male-1.68mm, female-2.33mm), in skeletal class III, the maxilla Is mote posteriorly located than the normal group. 3. The cause of malocclusion In skeletal class III patients, consists of retrognathic maxilla(A1) male $22\%$, female $26\%$, prognathic mandible(B1) male $44\%$, female $34\%$, and combination of an retrognathic maxilla and prognathic mandible were male $28\%$, female $38\%$. 4. There was no significant difference in the anterior-posterior length of the maxilla(A4) between skeletal class III males with the normal group, while in the female subjects, the skeletal class m group showed a smaller maxilla(A4) compared to the normal group. 5. In skeletal class III patients the proganthic mandible was primarily caused by the Inclination of the ramus(R3, R4) and mandibular body length(B4, B6) rather than ramus width(B3).

• The korean journal of orthodontics
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• v.19 no.1 s.27
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• pp.201-218
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• 1989

This study was focused on the distribution of different facial types of the Class II division I malocclusion groups and skeletal characteristics of the each group and those that anteropsterior relationship of the maxilla and mandible calculated from the analysis of ANB angle and Wits appraisal was quite different from each other, as well. Cephalometric headplates of 140 persons of Class II division 1 malocclusion whose mean age was 11.2 years and 69 persons of normal occlusion whose mean age was 12.2 years were utilize as materials. Measurements were recorded, tabulated and statistically analyzed employing the tracings of the lateral cephalograms, then Class II division 1 malocclusion group was divided into 9 Types according to the angle of SNA and SNB for the anteroposterior relationship of the maxilla and mandible, another 9 Types according to the FH-NPog and SN-MP for the horisontal and vertical relationship, and the other 9 Types according to the ANB and Wits appraisal for intermaxillary relationship as well, with which was based on $Mean{\pm}$ 1SD of those of normal occlusion. The result allowed the following conclusion: 1. $37.1\%$ of population demonstrated maxilla within nounal range and retrognathic mandible to the cranial base, $30\%$ for both maxilla and mandible within normal range, $20\%$ for retrognathic maxilla and mandible and $12.9\%$ of the rest were ananged in Class II division 1 maloccusion groups. 2. Retrognathic mandible and hyperdivergent face accounted for $30.7\%$, mesognathic mandible and neutrodivergent face for $29.3\%$, mesognathic mandible and hyperdivergent face for $16.4\%$, retrognathic mandible and neutrodivergent face for $13.6\%$, mesognathic mandible and hypodivergent face for $10\%$ of population were computed in Class II division 1 malocclusion groups. 3. It was suggested that skeletal Class II malocclusion might be due to anomaly in size and shape of cranial base, underdevelopment of mandible, retropositioning of mandible, underdevelopment of posterior face against anterior face, or any combination of these factors. 4. Population with underdevelopment and / or retropositioning of the mandible showed hyperdivergent tendency of facia profile. 5. The ANB angle and Wits appraisal did not coincide the severity of anteroposterior dysplasia in $35.7\%$ of Class II division 1 malocclusion group each other, and this inconsistency was suggested to be related with mandibular rotation, inclination of cranial base, and anteroposterior position of the maxilla.

• The korean journal of orthodontics
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• v.36 no.1 s.114
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• pp.63-73
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• 2006

Numbers of postulations lie on the difference of integumental changes with two major surgical remedies of one jaw vs. two jaw surgery in skeletal Class III malocclusion. Accordingly it was the aim of the study to elucidate the skeletal profile changes with an accompanying disposition of soft tissues, consequently to yield the correlation and ratio of soft tissue changes with two types of surgical procedures, which in turn make it possible to predict the soft tissue outcomes by means of assembled regression equations. Cephalometric headfilms of fifty two adult skeletal Class III comprised of 26 maxillary advancement by Le Fort I osteotomy and mandibular setback by sagittal split ramus osteotomy simultaneously (double jaw surgery, group A), 26 mandibular setback alone (one jaw surgery, group B) were statistically analyzed. Group A manifested 72.4% soft tissue advancement to skeletal changes in the upper lip area, while group B appeared to have no statistically significant changes. The nasolabial angle showed more increment in group A than in group B, whereas the mentolabial angle illustrated more reduction in group B. The backward movement of soft tissue pogonion to skeletal change revealed 98% in group A, and 109% in group B. The double jaw surgery group characteristically revealed remarkable integ umental change in the upper lip area, while the one jaw surgery had major effects in the lower lip and soft tissue pogonion areas.

• Journal of the korean academy of Pediatric Dentistry
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• v.42 no.2
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• pp.126-135
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• 2015

The purpose of this study was to evaluate the skeletal and dentoalveolar effects of facemask therapy and to compare the anchorage of a bonded expander in patients with Class III malocclusion and different vertical skeletal patterns. Twenty subjects with Class III malocclusion were included in this study and were treated with a facemask and bonded expander. Based on the FMA, subjects were divided into two groups of 10 patients each: a high vertical group (HV; mean FMA $33.56^{\circ}$) and an average vertical group (AV; mean FMA $24.88^{\circ}$). Lateral cephalograms were taken and evaluated before and after treatment. In both groups, forward movement of the maxilla and backward rotation of the mandible were observed after treatment, with no statistical differences between the groups. Vertical skeletal variables increased in both groups, but the increase of FMA was significantly larger in the HV group than the AV group. Mesial movement of maxillary molars and proclination of maxillary incisors which indicate anchorage loss of bonded expander were observed in both groups, with no significant differences between the groups. In conclusion, facemask therapy resulted in effective maxillary protraction in both HV and AV groups. However, the open bite tendency was increased more in the HV group.