• The korean journal of orthodontics
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• v.18 no.1 s.25
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• pp.235-252
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• 1988

The quadrilateral analysis is a proportional analysis which evaluates the skeletal configuration of lower face on the relations between both jaws in the horizontal as we]1 as vortical dimensions. This study was undertaken to analyse the harmony and disharmony of quadrilateral patterns in normal occlusion and malocclusion. The present study was carried out on lateral cephalograms of 530 Korean children; the subjects consisted of 135 normal occlusions (63 male and 72 female), 105 Class II division 1 malocclusions (52 male and 53 female), 109 Class III malocclusions (50 male and 59 female), 91 hypodivergent facial types (44 male and 47 female) and 90 hyperdivergent facial types (45 male and 45 female). The following conclusions were reached: 1. Means and standard deviation in each group and sex were obtained from normal occlusion and malocclusion. 2. Quadrilateral mean diagram in normal occlusion was constructed for male and female, respectively. 3. In normal occlusion, 1:1 ratio exists between the maxillary base length (A' to Ptm') and mandibular base length (B' to J'), but lower facial height is targer than above. 4. Difference is effective to estimate the degrees of Class II and Class III malocclusion, and lower facial height (LFH) and sagittal angle is effective to recognize the hypodivergent and hyperdivergent facial type. 5. Quadrilateral analysis is able to visualize the anteroposterior and vertical dysplasia of lower face, and it is helpful to recognize certain problems in malocclusion.

• The korean journal of orthodontics
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• v.49 no.5
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• pp.338-346
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• 2019

In this report, we describe the successful use of alternate rapid maxillary expansions and constrictions with a hybrid hyrax-mandibular miniplate combination and simultaneous orthodontic treatment for the management of severe Class III malocclusion due to maxillary hypoplasia in an 11-year-old girl. The devices were removed after 20 months of treatment, and the family was instructed about a careful control and retention program that should be followed in accordance with the patient's growth. The final result included the correction of Class III malocclusion with adequate function and excellent facial esthetics, which restored the patient's self-esteem and provided personal motivation. The outcomes showed good stability after 24 months of retention. The decrease in the duration of active treatment is the most important finding from the present case. Considering that facial esthetics in adolescence is a determining factor for the development of a personality and interpersonal relationships, we recommend the use of this protocol for growing patients, who will exhibit not only an improved physical appearance but also a better quality of life.

• Korean Journal of Cleft Lip And Palate
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• v.20 no.1
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• pp.49-58
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• 2017

We report the rehabilitation of Class II malocclusion with multiple teeth fracture due to trauma. A multidisciplinary team approach was necessary to treat patient's problems such as bone fracture, malocclusion, and multiple teeth fracture. Emergency conservative treatment, orthodontic treatment and prosthetic restoration successfully restored the occlusion. However, special considerations were needed along the orthodontic treatment process due to the unexpected complications such as ankylosis, root resorption and detection of additional teeth fractures.

• Imaging Science in Dentistry
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• v.50 no.2
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• pp.105-115
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• 2020

Purpose: This study investigated the position of the hyoid bone and its relationship with airway dimensions in different skeletal malocclusion classes using cone-beam computed tomography (CBCT). Materials and Methods: CBCT scans of 180 participants were categorized based on the A point-nasion-B point angle into class I, class II, and class III malocclusions. Eight linear and 2 angular hyoid parameters(H-C3, H-EB, H-PNS, H-Me, H-X, H-Y, H-[C3-Me], C3-Me, H-S-Ba, and H-N-S) were measured. A 3-dimensional airway model was designed to measure the minimum cross-sectional area, volume, and total and upper airway length. The mean crosssectional area, morphology, and location of the airway were also evaluated. Data were analyzed using analysis of variance and the Pearson correlation test, with P values <0.05 indicating statistical significance. Results: The mean airway volume differed significantly among the malocclusion classes(P<0.05). The smallest and largest volumes were noted in class II (2107.8±844.7 ㎣) and class III (2826.6±2505.3 ㎣), respectively. The means of most hyoid parameters (C3-Me, C3-H, H-Eb, H-Me, H-S-Ba, H-N-S, and H-PNS) differed significantly among the malocclusion classes. In all classes, H-Eb was correlated with the minimum cross-sectional area and airway morphology, and H-PNS was correlated with total airway length. A significant correlation was also noted between H-Y and total airway length in class II and III malocclusions and between H-Y and upper airway length in class I malocclusions. Conclusion: The position of the hyoid bone was associated with airway dimensions and should be considered during orthognathic surgery due to the risk of airway obstruction.

• The korean journal of orthodontics
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• v.47 no.5
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• pp.277-288
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• 2017

Objective: Treating Class II subdivision malocclusion with asymmetry has been a challenge for orthodontists because of the complicated characteristics of asymmetry. This study aimed to explore the characteristics of dental and skeletal asymmetry in Class II subdivision malocclusion, and to assess the relationship between the condyle-glenoid fossa and first molar. Methods: Cone-beam computed tomographic images of 32 patients with Class II subdivision malocclusion were three-dimensionally reconstructed using the Mimics software. Forty-five anatomic landmarks on the reconstructed structures were selected and 27 linear and angular measurements were performed. Paired-samples t-tests were used to compare the average differences between the Class I and Class II sides; Pearson correlation coefficient (r) was used for analyzing the linear association. Results: The faciolingual crown angulation of the mandibular first molar (p < 0.05), sagittal position of the maxillary and mandibular first molars (p < 0.01), condylar head height (p < 0.01), condylar process height (p < 0.05), and angle of the posterior wall of the articular tubercle and coronal position of the glenoid fossa (p < 0.01) were significantly different between the two sides. The morphology and position of the condyle-glenoid fossa significantly correlated with the three-dimensional changes in the first molar. Conclusions: Asymmetry in the sagittal position of the maxillary and mandibular first molars between the two sides and significant lingual inclination of the mandibular first molar on the Class II side were the dental characteristics of Class II subdivision malocclusion. Condylar morphology and glenoid fossa position asymmetries were the major components of skeletal asymmetry and were well correlated with the three-dimensional position of the first molar.

• Journal of the korean academy of Pediatric Dentistry
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• v.8 no.1
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• pp.77-88
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• 1981

The purpose of this study was to make a comprehensive study & evaluation of the oral status of mental retarded children. The auther examined intraorally 486 (male; 311, female;175) mental retarded children. The result was as follows; (General mental retarded children means the children who live in their parent's home, & orphan mental retarded children means the children who live in orphanage.) 1. The dft rate was 31.6% in general mental retarded children (G.m.r.c.) & 20.7% in orphan mental retarded children (O. m. r. c.). The dft index was 3.73 in G.m.r.c. & 2.15 in O.m.r.c. 2. The DMFT rate was 24.6% in female G.m.r.c., 16.7% in male G.m.r.c., 12.7% in female O.m.r.c., 8.4% in male O.m.r.c. The DMFT index was 4.94 in female G.m.r.c., 4.01 in male G.m.r.c., 1.40 in male O.m.r.c., 2.75 in female O.m.r.c. 3. The malocclusion prevalence was 57.3%. the class I malocclusion was 14.2% Class II malocclusion 19.3%, Class III malocclusion 23.5%. The children with Down's syndrome had 60.0% of class III malocclusion prevalence. 4. The dental calculus index was 1.97 in male O.m.r.c., 1.81 in female O.m.r.c., 1.30 in male G.m.r.e., 1.13 in female G.m.r.c. 5. The dental plaque index was 3.06 in female G.m.r.c., 3.00 in male Gm.r.e. 2.70 in male O.m.r,c., 2.32 in female O.m.r.c.

• The korean journal of orthodontics
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• v.38 no.6
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• pp.388-396
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• 2008

Objective: The purpose of this study was to evaluate the effects of malocclusion on the self-esteem of female university students. Methods: The subjects were composed of 67 female university students who showed Class 1 molar relation, no missing or supernumerary teeth and has had no orthodontic treatment experience. Each subject was evaluated with Rosenberg's Self-esteem Scale to measure the level of self-esteem and also evaluated the degree of anterior crowding and lip protrusion through model analysis and cephalometric soft tissue profile analysis. Results: The results showed that a protrusive profile and crowding of upper anterior teeth had significant reducing effects on the level of self-esteem. The protrusion and crowding groups showed no significant differences in self-esteem between groups. Conclusions: Malocclusion had significant negative effects on the self-esteem of female university students. Further research to investigate the negative psychological influence of malocclusion and the education of lay people about this influence is necessary.

• The korean journal of orthodontics
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• v.13 no.1
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• pp.31-43
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• 1983

The following results were abtained based on the research of the occlusal patterns among 1074 handicapped persons (cerebral palsy: 46, mental subnormality: 619, deafmute: 285, blind: 111, childish autism:8, cleft lip and cleft palate:3, polimyelitis:2) of the age between 6 and 23 in Chollanamdo, Korea, in comparison with a normal group of 1048 children of the age between 6 and 15 selected at random in J primary school in Gwang-ju City. 1. According to Angle's malocclusion classification, all the handicapped groups, except the cerebral palsy and the blind, showed a higher prevalence of malocclusion than that of the normal. Especially the prevalence of Class II, devision 1 malocclusion in the cerebral palsy was the highest, and the prevalence of Class III malocclusion in all the handicapped groups was higher than that of the normal group. Among these groups the highest prevalence of Class III malocclusion was in the Down's syndrome group. 2. On the the abnormal pattern of the anterior region, there was no significant difference $(P\leqq0.05)$ between the normal and the cerebral palsy, the deafmute, and e blind. The open bite $(7.27{\pm}1.04\%)$ and the cross-bite $(32.7{\pm}6.33\%)$ of the Down's syndrome wire higher than that of the normal, and the forward position of the mandible could be recognized in the Down's syndrome group. 3. On the midline position of the dentition, all the handicapped showed the same percentage of deviation, but the degree of mandibular shift to the right $(20.00{\pm}5.39\%)$ or left $(10.91{\pm}4.20\%)$ was higher than that of the normal only in the Down's syndrome group. 4. On the abnormal pattern of the posterior region, the cross-bite of the Down's syndrome was higher than that of the normal by $20.00{\pm}5.39\%$, the cross-bite of the cerebral palsy and the cross-bite and the open bite of the mental subnormality were slightly higher than that of the normal. The other handicapped groups showed no significant difference $(P\leq0.05)$ to the normal.

• The korean journal of orthodontics
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• v.50 no.5
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• pp.304-313
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• 2020

Objective: The aim of this study was to evaluate the stability of bimaxillary surgery involving bilateral intraoral vertical ramus osteotomy performed with or without presurgical miniscrew-assisted rapid palatal expansion (MARPE) in adult patients with skeletal Class III malocclusion. Methods: A total of 40 adult patients with skeletal Class III malocclusion were retrospectively divided into two groups (n = 20 each) according to the use of MARPE for the correction of transverse maxillomandibular discrepancy during presurgical orthodontic treatment. Serial lateral cephalograms and dental casts were analyzed until 6 months after surgery. Results: Before presurgical orthodontic treatment, there was no significant differences in terms of sex and age between groups. However, the difference of approximately 3.1 mm in the maxillomandibular intermolar width was statistically significant (p < 0.001). Two days after surgery, the mandible had moved backward and upward without any significant intergroup difference. Six months after surgery, the maxillary intercanine (2.7 ± 2.1 mm), interpremolar (3.6 ± 2.4 mm), and intermolar (2.0 ± 1.3 mm) arch widths were significantly increased (p < 0.001) relative to the values before presurgical orthodontic treatment in the MARPE group; these widths were maintained or decreased in the control group. However, there was no significant difference in surgical changes and the postsurgical stability between the two groups. No significant correlations existed between the amount of maxillary expansion and postsurgical mandibular movement. Conclusions: MARPE is useful for stable and nonsurgical expansion of the maxilla in adult patients with skeletal Class III malocclusion who are scheduled for bimaxillary surgery.

• International Journal of Oral Biology
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• v.43 no.2
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• pp.101-111
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• 2018

Understanding the classification of malocclusion is a crucial issue in Orthodontics. It can also help us to diagnose, treat, and understand malocclusion to establish a standard for definite class of patients. Principal component analysis (PCA) and k-means algorithms have been emerging as data analytic methods for cephalometric measurements, due to their intuitive concepts and application potentials. This study analyzed the macro- and meso-scale classification structure and feature basis vectors of 1020 (415 male, 605 female; mean age, 25 years) orthodontic patients using statistical preprocessing, PCA, random matrix theory (RMT) and k-means algorithms. RMT results show that 7 principal components (PCs) are significant standard in the extraction of features. Using k-means algorithms, 3 and 6 clusters were identified and the axes of PC1~3 were determined to be significant for patient classification. Macro-scale classification denotes skeletal Class I, II, III and PC1 means anteroposterior discrepancy of the maxilla and mandible and mandibular position. PC2 and PC3 means vertical pattern and maxillary position respectively; they played significant roles in the meso-scale classification. In conclusion, the typical patient profile (TPP) of each class showed that the data-based classification corresponds with the clinical classification of orthodontic patients. This data-based study can provide insight into the development of new diagnostic classifications.