• The korean journal of orthodontics
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• v.25 no.3 s.50
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• pp.355-373
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• 1995

Craniofacial region is a musculodentoskeletal system that consists of many anatomical structures ; cranioskeletal structures, dental arches, and formation and functions of masticatory muscles have close correlations. Growth and development of craniofacial region are influenced by not only hereditory factors, but also environmental factors such as craniofacial muscles and surrounding tissues. On the contrary, however, study on changes in functions or adaptations of craniofacial muscles following changes of craniofacial skeletal structures has been somewhat insufficient. The author's purpose was to observe correlations between masticatory muscular functions and change patterns according to cranial skeletal structures and occlusion patterns, for this, comparative study of muscle activity changes of preand post- orthognathic surgery states in skeletal Cl III malocclusion patients was peformed. The selected sample groups were 15 normal male patients, 15 skeletal Cl III pre-orthognatic surgery patients and 15 skeletal Cl III post-orthognatic surgery patients. For each sample groups, cephalometric x-ray taking, masticatory efficiency test and measurements of muscle activities in anterior temporal muscle, masseter and upper lip in rest, clenching, chewing and swallowing were carried out. The following results were obtained : 1. In resting state of mandible, pre-surgery malocclusion group showed higher m. activities in ant. temporalis, masseter and upper lip than post-surgery group. Post-surg. malocc. group showed significantly high m. activity only in upper lip compared to the normal group. 2. In clenching state, post-surg. malocc. group showed higher m. activities in ut. temporalis, masseter and upper lip than pre-surg. malocc. group. 3. In chewing state, post-surg. malocc. group showed higher m. activities in ant. temporalis and masseter than pre-surg. malocc. group, on the other hand, decreased upper lip activity was noticed. 4. In swallowing state, post-surg. malocc. group showed lower upper lip activity than pre-surg. malocc. group but higher than that of the normal group. No significant difference in m. activities of ant, temporalis and masseter was noticed among the three groups. 5. Masticatory efficiency was lower in pre-surg. malocc. group than normal group, masticatory efficiency showed an increase in post-surg. malocc. group compared to the pre-surg. malocc. group. However, both groups showed significant differences compared to the normal group.

• The korean journal of orthodontics
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• v.35 no.1 s.108
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• pp.23-34
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• 2005

Collective changes caused by orthodontic tooth movement evaluated in a specific treatment modality could give suggestive information on the specific treatment strategy. The aim of this study was to investigate retrospectively the characteristics of the orthodontic tooth movement during surgical-orthodontic treatment in order to provide an effective presurgical orthodontic treatment planning for the maxillary premolar extraction modality In the skeletal Class III malocclusion patient. Pre- and post-treatment dental casts of skeletal Class III malocclusion patients with nonextraction (N=:24) and the maxillary premolar extraction (N=31) were collected. The angulation and inclination measuring gauge(Invisitech Co. Seoul, Korea) was used to evaluate the orthodontic tooth movement. The changes in the maxillary and mandibular dental arch widths were also measured from the canines to the second molars. As a result, more palatal inclination change in the maxillary dentition was found with the premolar extraction modality than with the nonextraction modality. Linear regression analysis showed that the inter-arch width coordination was mainly due to the inclination changes of maxillary posterior teeth We conclude that the indications and proper treatment planning for surgical-orthodontic treatment in skeletal Class III malocclusion with maxillary premolar extraction could depend partly on the magnitude of the transverse inter-arch coordination especially in the maxillary dentition.

• The korean journal of orthodontics
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• v.30 no.5 s.82
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• pp.643-655
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• 2000

In Patients with severe skeletal discrepancy, surgical orthodontic treatment must be accompanied, and recently two jaw surgery has become a common procedure, resulting in improved esthetics and function. Choosing the position of the occlusal plane in this two jaw surgery is an important factor in postoperative stability Therefore this must be taken into consideration during the diagnosis and treatment plan. In this study, among patients with skeletal Class III occlusion, 25 patients(8 male, 17 female, average age $23.2{\pm}3.17$) who have undergone two jaw surgery, setting the ideal occlusal plane according to Delaire's architectural and structural cranial analysis. In comparing preoperative($T_1$). postoperative($T_2$, average of 15.4 days), and long-term postoperative($T_3$, average of 32.6 months) lateral cephalometric radiography, the following conclusions have been made. 1. There were no significant changes of the occlusal plane angle after the two jaw surgery, and there were no significant differences between the surgical technique(SSRO and IVRO). 2. The postoperative changes of the occlusal Plane had no relationship with the amount of jaw movement, amount of posterior impaction, nor the time relapse after surgery. 3. After two jaw surgery, in the SSRO group there was significant forward movement of the mandible, and in the IVRO group the lower incisors extruded as the mandible moved backward and downward which makes the genial angle and the mandibular plane angle significantly increased

• Journal of the korean academy of Pediatric Dentistry
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• v.40 no.4
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• pp.296-305
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• 2013

For the purpose of evaluating the prevalence of malocclusion and self-esteem in adolescents, 1,380 middle-school students in the Yangsan area were surveyed by oral examination and questionnaires and the obtained results were as follows: The distribution of 1st molar occlusion by Angle's classification was 69.0, 19.4, 10.6% for Class I, II and III respectively. In the horizontal relationship, the prevalence of normal overjet and crossbite was 86.9% and 5.6% respectively whereas larger and extremely larger overjet was found in 6.6% and 0.8%. In the vertical relationship of anterior teeth, normal, deep overbite and openbite was shown in 94.1%, 4.7%, and 1.2%. For the midline discrepancy, the distribution of groups with 0~1 mm, 2~4 mm and over 5 mm was 98.2%, 1.4%, and 0.4%. Crowding only in the maxilla was found in 9.6%, while that only in the mandible and in both arches was 14.1% and 24.1% respectively. Spacing only in the maxilla was seen in 3.0%, while that only in the mandible and in both arches was 2.4% and 1.7% respectively. Significant difference in self-esteem was revealed in female and malocclusion groups of crossbite and openbite(p < 0.05).

• The korean journal of orthodontics
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• v.27 no.3 s.62
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• pp.359-372
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• 1997

This study was conducted to discern differences of craniofacial, dentoalveolar structure and model measurements between sex and between class n openbite group and non-openbite group. The sample consisted of 49 adult patients with class Il malocclusion. 24 linear measurements, 22 angular measurements and 12 ratios were selected in lateral cephalometry. Also, arch width, length, anterior crowding, average molar relation were measured or calculated in diagnostic model. The data were evaluated by t-test and multiple discriminant analysis. The results were as follows, 1. Most linear measurements, with the exception of MnBL and AUDH, were significantly larger in male(p<0.05). but, intermaxillary relations and spatial position of maxilla and mandible relative to cranial base were not different for both sex. 2. With the exception of upper and lower anterior crowding, lower arch width, upper arch length, AMR, male exhibited significantly larger measurements in model analysis (p<0.05). 3. Size differences of maxilla and mandible between openbite and non-openbite group were not significant(p>0.05). but openbite group showed significantly increased genial angle(p<0.05), FH-CoGo(p<0.01), FH-NA(p<0.01) and FH-NB, FH-NPog (p<0.05). 4. ALFH and PUDH were larger(p<0.05) in openbite group. this result served as compensation for the spatial position of mandible relative to cranial base. AUPUDH (p<0.001) and ALPLDH(p<0.05) were lower in openbite group. upper anterior crowding was the only measurement which showed difference between openbite and non-openbite group(p<0.05). 5. For the purpose of classifying adult class n openbite and non-openbite group, multiple discriminant analysis was done genial angle, ALPLDH, AUPUDH, FH-NA were included in multiple discriminant equation. 39 cases($92.86\%$) were correctly classified when applied to the sample used in this study.

• Journal of the korean academy of Pediatric Dentistry
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• v.40 no.1
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• pp.21-27
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• 2013

In growing children it is frequently found that dental maturation is strongly influenced by the growth rate of maxilla or mandible. If there is evidence to prove this, it might be utilized as a criterion in the early diagnosis of skeletal malocclusion, even before the object's real skeletal features are yet revealed. The purpose of this study was to find out if the difference of dental maturation in over-grown mandible in children with skeletal Class III has any relationship with some skeletal features of mandible. 50 patients in Hellman dental age IIIA with normal occlusion and Class III malocclusion of mandibular over-growth type respectively were selected as study objects. The age estimation was performed on maxillary and mandibular teeth, eruption rate of the 2nd molars of each group have been measured on panoramic radiography, and the differences in dental age of the upper and lower jaw were analyzed under Demirijian's method. The results were as follows: The difference of dental age of maxillary and mandibular teeth between the two groups was 0.66 and 1.20 years respectively, with a higher difference in the experimental group (p < 0.05). The difference of eruption rate of the maxillary and mandibular second molar was not found between two group (p >0.05).

• The korean journal of orthodontics
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• v.28 no.2 s.67
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• pp.237-253
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• 1998

Surgical-orthodontic treatment is performed for the skeletal Class III patients with no remaining growth and too big a skeletal discrepancy (or camouflage treatment, and two jaw surgery is needed in order to have maximum effect in such patients. In two jaw surgery cases, surgical alteration of the occlusal plane is necessary to establish optimal function, esthetics and postoperative sability, therefore the establishment of the occlusal plane is essential in diagnosis and treatment. The object of this study is to evaluate the stability of the indiviual ideal occlusal plane bsaed on the architectural and structural craniofacial analysis of Delaires. Thus, the subjects of this study were 48 patients who underwent two jaw surgery, and divided in two groups. Each group were composed of 24patients, A group were operated with ideal occlusal plane and B group were not. Two groups were compared at the preoperative, immediate postoperative (average 4.3days), and long-term postoperative (average 1.3years) lateral cephalometric radiographs. The following results were obtained: 1. There was no significance in occlusal plane angulation between $T_2\;and\;T_3$. Average long term follow-up changes of occlusal Plane angle were $0.24^{\circ}{\pm}2.43$, with FH plane and $0.15{\circ}{\pm}2.16{\circ}$ with SN plane in all 48 patients. These results demonstrated that the occlusal plane after two jaw surgery in skeletal Class III malocclusion was stable. 2. There was no significance in postoperative stability of occlusal plane between A and B group. 3. There was no significance in postoperative stability of occlusal plane depending on surgeon and operative method within each group. 4. The postoperative changes of occlusal plane were correlated to the postoperative changes of jaw rather than tooth position. 5. There was no correlation between the postoperative changes of occlusal plane and maxillary impaction and mandibular setback with surgery.

• Journal of dental hygiene science
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• v.14 no.3
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• pp.390-396
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• 2014

The purpose of this study was to examine the size, form of dental arch and occlusion type in college students in our country and the relationship of the factors. The subjects in this study were 210 selected dental hygiene students. The collected data were analyzed by a statistical package PASW 18.0. When their size, form and occlusion of dental arch were analyzed, the inter-canine width of the maxillary was 34.38 mm, and the inter-first molar width was 52.05 mm. The canine depth was 8.60 mm, and the first molar depth was 28.69 mm. As for the mandibular, the inter-canine width was 26.42 mm, and the inter-first molar width was 44.83 mm. The canine depth was 5.54 mm, and the first molar depth was 24.38 mm. Concerning the form of dental arch, the percentage of normal dental arch in the maxillary stood at 29.0, and that of crowding stood at 60.5. The percentage of spacing stood at 10.5. In the case of the mandibular, the percentage of normal dental arch stood at 29.0; crowding, 55.7; and spacing, 15.2. In relation to occlusion, the percentage of normal occlusion stood at 16.7. As to malocclusion, class I that accounted for 55.7 was most common, and class II and class III respectively accounted for 20.5 and 7.1. When the size of dental arch was compared according to the form and occlusion of it, dental arch was largest (45.95 mm) in size when the form of dental arch in the inter-first molar width of the mandibular was spacing. The size of dental arch was 44.73 mm when its form in the same region was normal, and that was 44.58 mm when its form in the same region was crowding (p=0.032). Regarding the relationship between the form and occlusion of dental arch, crowding was most common when there were class I, II and III of malocclusion both in the maxillary and mandibular.

• The korean journal of orthodontics
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• v.25 no.5 s.52
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• pp.543-555
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• 1995

In the orthopedic therapy, the biomechanical analysis of the appliance is necessary to get a desirable orthopedic effect. The purpose of this study was to investigate the desirable direction and application position of the protraction force. The protraction force of 500g was applied to the first premolar or to the first molar. The direction of force application was paralell or $20^{\circ}$ downward to the occlusal plane respectively. The stress distribution and the displacement within the maxilla was analyzed by a 3-dimensional finite element method. The findings obtained were as follows 1. Protraction forces caused a counterclockwise rotation of the maxilla. 2. The degree of maxillary rotation was less when the force was applied $20^{\circ}$ downward direction to the occlusal plane than when applied to the parallel direction. 3. The degree of rotation of maxilla was greater when the parallel force was applied to the 1st premolar than when applied to the first molar, whereas it was greater when force is applied $20^{\circ}$ downward than at the first premolar. In conclusion, the $20^{\circ}$ downward protraction from the first premolar induced the least counterclockwise rotation of the maxilla and was thought as the desirable direction and application position of the protraction force.

• The korean journal of orthodontics
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• v.30 no.2 s.79
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• pp.143-157
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• 2000

To investigate the developmental stages of dental and skeletal maturation by ages and the correlations among dental maturity, skeletal maturity of cervical vertebrae, and that of hand-and-wrist, the author used the cephalograms, orthopantomograms, and hand-and-wrist radiograms of 1055 patients (male 458, female 597) aged 7 to 20 years old. In the cephalograms, the skeletal maturity stages of each bone were mainly assessed by Hassel and Farman's cervical vertebrae maturation indicators (CVMI) method. In the orthopantomograms, the dental maturity stages of each tooth were mainly assessed by Nolla's tooth calcification stages method. In the hand-and-wrist radiograms, the skeletal maturity stages of each bone were mainly assessed by Fishman's skeletal maturity indicators (SMI) method. The results were as follows. 1. There was a high correlation among dental maturity, skeletal maturity of cervical vertebrae, and that of hand-and-wrist in the both sexes (P<0.001). 2. There was a high correlation (r=0.91-0.93) between skeletal maturity of cervical vertebrae and that of hand-and-wrist. 3. There was a high correlation (r>0.8) between skeletal maturity of hand-and-wrist and maturity of upper and lower canine, first premolar, and second premolar. 4. There was high a correlation(r=0.8) between skeletal maturity of cervical vertebrae and maturity of upper canine. 5. By the ages, dental maturity, skeletal maturity of cervical vertebrae, and that of hand-and-wrist were obtained in the both sexes. In summary, dental maturity, skeletal maturity of cervical vertebrae, and that of hand-and-wrist we of sufficient diagnostic worth as an index to predict adolescent growth.