• The korean journal of orthodontics
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• v.15 no.2
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• pp.303-312
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• 1985

This study was designed to get the knowledge of the structural characteristics of the lingual dental arch shapes of Koreans. The subjects consisted of 107 normal occlusions. The lingual structure which was divided into two groups, anterior and posterior part, was measured and analyzed. 33 pairs of the 107 samples were used to test the derived results. The findings of this study were as follows: 1. The mathmatical functions of the 12 curves which showed good fitting to the upper and lower anterior lingual arch were derived and flawed to the same scale using the computer graphics. 2. The results of the test showed a reasonable degree of accuracy to all of the 33 random samples. 3. The average degrees of posterior flexions were obtained and could be used as a initial guide at the wire-bending.

• The korean journal of orthodontics
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• v.15 no.2
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• pp.353-368
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• 1985

This present paper describes 3 clinical cases which were treated with Bioprogressive mechanism. Each patient has shown a deficient maxilla combined with prognathic and steep mandible. The purpose of treatment was planned to obtain the forward growth of maxilla and redirectioning of mandibular growth. The most noteworthy approach in the treatment was the application of Cl III intermaxillary elastics with upper protraction utility arch immediately after rapid maxillary expansion. In the analysis of the data obtained from pre- and post treatment lateral cephalogram, the result achieved by this method is very favolable to the correction of anteroposterior relationship of maxilla and mandible.

• The korean journal of orthodontics
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• v.15 no.1
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• pp.93-103
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• 1985

Since the fact was known that mouth breathing resulted from the adenoid hypertropy causes malocclusion, many investigators have studied nasopharynx and adenoid in order to clarify the role in relation to the effect on face and occlustion and the development of airway. The author analyzed 13 items in longitudinal cephalometric roentgenograms of 17 boys and 19 girls taken from the age of 7 to 12. The results were as follows. 1. The means and standard deviation for the measured items were obtained. 2. The continual growth of nasopharyngeal cavity was more affected by the height than the depth. 3. The size of adenoid was larger in males than in females, especially on R, $D-AD_2$. 4. Airway percentage was highest in boys at age 10 and girls at age 9. 5. The items showed significant differentiation between males and females were airway percentage, posterior height, $D-AD_1,\;D-AD_2$, and R.

• The korean journal of orthodontics
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• v.21 no.3
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• pp.657-670
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• 1991

It was said that early rapid palatal expansion was the treatment of choice in case of maxillary constriction with posterior crossbite. The author tried to assess dimensional changes of nasal and oral cavity before rapid palatal expansion and over 4 months of retention by use of three coronal tomograms through the incisal, molar, and maxillary tuberosity areas. The subjects of this study were consisted of 9 boys and 11 girls ranging from 11 to 13 years old. The results were as follows: 1. A mean change in maxillary first molar width was 3.68mm and a mean change in nasal cavity width was 2.26mm after 6.70mm expansion by Hyrax-type screw and over 4 months of retention tomographically in molar cut. 2. A change in nasal cavity width tomographically showed in order of molar cut, incisal cut, maxillary tuberosity cut respectively. 3. There was no correlation between changes in oral cavity width and nasal cavity width.

• The korean journal of orthodontics
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• v.21 no.3
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• pp.581-590
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• 1991

This study was carried out for the comparison of the head postures between mouth breathers and normal nasal breathers. For this purpose, a test group of 28 mouth breathers, between the ages of 8 to 12 years old and a control group of 25 nasal breathers were used. Following results were obtained after comparing the craniofacial and craniocervical angulations to the True Vertical line. 1. In the comparisions relating to the True Vertical Line, results were obtained using four items; NSL/VER, FH/VER, NL/VER, PMV/VER. Variations were observed in all the items and the craniofacial angulations in the mouth breathers group showed more superior position compared to the control group. 2. In the comparisions relating to the craniocervical angulations, results were obtained using four items; NSL/OPT, FH/OPT, NL/OPT, PMV/OPT. Variations between the two groups were observed only in the PMV/OPT item and the mouth breather group showed more craniocervical angulations compared to the control group.

• The korean journal of orthodontics
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• v.20 no.3 s.32
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• pp.553-564
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• 1990

The purpose of this study was to compare mandibular teeth development of Angle Class I malocclusion group with that of Angle Class III malocclusion group. The studied subjects consisted of 217 Angle Class I malocclusion patients and 235 Angle Class III malocclusion patients. Two study methods were used. One was to evaluate tooth development degree by means of Nolla stage method, the others was to measure tooth length on panoramic radiograph. The following results were obtained, in 7, 8 and 9 years, tooth development of Angle Class III malocclusion group was significantly faster than that of Angle Class I malocclusion group. in 6 year and 10, 11, 12, 13, 14 years, the difference of tooth development degree between Angle Class III malocclusion group was not significant.

• The korean journal of orthodontics
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• v.24 no.2
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• pp.405-417
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• 1994

The purpose of this study was to investigate proportional characteristics of soft tissue profile in Korean young adults. The sample consisted of 50 young adults(25 males and 25 females) who had pleasing profile and normal occlusion. Soft tissue proportional analysis was performed on lateral cephalograms taken in natural head position. The results were as follows : 1. Mean and standard deviation of proportional analysis were obtained. 2. Horizontal and vertical dimensions were larger in male. But facial proportion had no sexual difference except upper/lower face height (p<0.05). Upper/lower face height was larger in female than in male. 3. Vertical dimensions, except SN-ST, had high correlation with horizontal dimensions. 4. Head positioning error of natural head position was smaller than inter -individual variability of SN line.

• The korean journal of orthodontics
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• v.24 no.2
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• pp.319-329
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• 1994

This study was carried out to research the adaptation patterns of head posture after activator therapy in functional class III malocclusion patients. For this purpose, 29 functional class III malocclusion patients, from the ages of 8 to 13 years old, were used. 1, Increse in capacity of oral cavity capacity were found in all the samples, but craniocervical angulation were varied into incresed group and decreased group after activator therapy. 2. Head posture exhibited the compensatory adaptation in the relative growth increments of the vertical dimension, ALFH and PLFH. 1) A group with more PLFH and less sagittal angle showed relatively small growth increment in PLFH during the treatment period, thus craniocervical angulation was increased. 2) A group with less PLFH and more sagittal angle showed relatively great growth incrmenet in PLFH during the treatment period, thus craniocervical angulation was decreased.

• The korean journal of orthodontics
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• v.24 no.2
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• pp.295-301
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• 1994

The movement of teeth during orthodontic treatment requires bone remodeling process in periodontal tissue. To find out the changes occuring in the cell itself, mechanical force was applied to the cultured periodontal ligament cells. Following results were obtained from measuring the changes in cyclic AMP and $PGE_2$, $^3H$-thymidine incorporation amount in time lapse after application of mechanical force. 1. When mechanical force was applied to cultured PDL cells, the amount of cAMP in cells were increased significantly after 15 min. of force application, but were decreased gradually as time lapsed. 2. When mechanical force was applied to cultured PDL cells, the amount of PGE2 were increased at 20,40,60 min. and was significantly increased at 20 min. 3. When mechanical force was applied to cultured PDL cells, the amount of $^3H$-thymidine incorporation was some increased, but was not statistically significant.

• The Journal of the Korean dental association
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• v.16 no.11 s.114
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• pp.849-856
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• 1978

Relapse following rotational movement of the tooth is a common problem in orthodontic practice. To overcome such relapse, many procedures have been advocated: prolonged retention, permanent retention, over-rotation, rotation of teeth at an early age, surgical procedures such as gingivectomy, redressement force, septotomy, et cetra. A 23-year-old woman presented with Angle's Class I malocclusion and extreme rotation of maxillary central incisors. After 15 months' active therapy, septotomy was performed on maxillary central incisors and Howley retainer was applicated for the purpose of overcoming rotational relapse. During the 1 year post-operative observation, negligible, if any, rotational relapse occurred.