• The korean journal of orthodontics
• /
• v.27 no.2
• /
• pp.209-219
• /
• 1997

This investigation was designed to analyze the degree of dental compensation according to horizontal components of craniofacial skeleton and to investigate correlation between dental compensation and craniofacial pattern in skeletal class III malocclusion. The material selected for this study consisted of standard lateral cephalogram of 59 subjects in normal occlusion group, 91 subjects in mild skeletal class III malocclusion group and 58 subjects in severe skeletal class III malocclusion group. The mild skeletal class III malocclusion group was divided into two groups, one was class III malocclusion without anterior crossbite group and the other was class III malocclusion with anterior crossbite group. The data were analyzed by Quick-ceph image program. The results were as follows. 1. Mild skeletal class III malocclusion without anterior crossbite group showed the most labial inclination of upper incisors, followed by severe skeletal class III malocclusion group and mild skeletal class III malocclusion with anterior crossbite group, the Latter showing the least. The amount of lingual inclination of lower incisors was the largest in severe skeletal class III malocclusion group, and there was no statistically significant difference between mild skeletal claw III malocclusion without anterior crossbite group and mild skeletal class III malocclusion with anterior crossbite group. 2. There were little differences in vertical skeletal structure between mild skeletal class III malocclusion without anterior crossbite group and mild skeletal class III malocclusion with anterior cwssbite group, they showed statistically significant differences in the upper incisors measurements. 3. The measurements of lower incisors in mild skeletal class III malocclusion without anterior crossbite group and upper incisors in mild skeletal class III malocclusion with anterior crossbite group represented a high correlation with skeletal structure. Especially, ∠IMPA and ∠FMIA of lower incisor measurements, and ∠U1-FH ∠U1-SN of upper incisor measurements showed high correlation with skeletal structure in each group. 4. ∠IMPA and ∠FMIA of lower incisor measurements showed high correlation with skeletal structure in all groups. ∠U1-FH, ∠U1-SN and U1-facial plane(mm) of upper incisor measurements represented higher correlation with skeletal structure than any other upper incisor measurements.

• The korean journal of orthodontics
• /
• v.35 no.6 s.113
• /
• pp.420-432
• /
• 2005

Bolton analysis is widely used to predict tooth size discrepancy. but its accuracy has been challenged. The purpose of this study was to describe true anterior tooth size discrepancies among orthodontic patients and to evaluate the factors that affect true anterior tooth size discrepancies. The subjects consisted of 80 patients with varying malocclusions (Class I. Class II. Class III. and Class III surgery) who were treated orthodontically. Pre-treatment models. set-up models from post-treatment models. and lateral cephalometric radiographs were analyzed The results were as follows. The means. the standard deviations. and ranges of anterior Bolton ratio in the present study were somewhat higher than those of Bolton's samples and Korean normal samples. The number of patients showing maxillary deficiency was larger than that of patients showing maxillary excess in view of true anterior discrepancies. There was a significant difference between anterior Bolton discrepancy from pre-treatment models and true anterior discrepancy from set-up models (p < 0.05) There was no significant difference in true anterior discrepancies among malocclusion groups (p > 0.05). And there was also no significant difference between the male and female groups (p> 0.05). Overbite and the incisal edge thickness of maxillary anterior teeth have little relationship with true anterior discrepancies. Multiple regression analysis showed that true anterior discrepancy was mainly determined by anterior Bolton ratio, upper incisor to occlusal plane angle after treatment. interincisal angle after treatment. and upper right lateral incisor width.

• The korean journal of orthodontics
• /
• v.34 no.6 s.107
• /
• pp.488-496
• /
• 2004

The purpose of the present study was to investigate the relationship of dental crowding to tooth size and arch dimension in Korean subjects. Two groups of dental casts with Class I molar relationship, were selected on the basis of crowding. One group, consisting of 82 pairs of study cast (29 males and 53 females), exhibited at least 7 millimeters of crowding in each arch. A second group, consisting of 82 sets of study cast (37 males and 45 females), exhibited normal occlusion with little or no crowding. Mesiodistal tooth diameters, and buccal and lingual dental arch widths were measured and compared between the crowding and normal occlusion groups. Significant differences were observed between the two groups not only in arch widths but also in tooth sizes. The results of the present study suggest that both extraction and expansion can be used as a treatment approach for the crowding cases.

• The korean journal of orthodontics
• /
• v.22 no.2 s.37
• /
• pp.413-426
• /
• 1992

In order to analyze the relationship between teeth and basal bone for the maintainance of the good occlusion, the mesiodistal width of teeth, the basal arch width and the basal arch length were measured on the study model of the normal occlusion group and Angle's class I malocclusion group (non-extraction group, extraction group) The Maximum tooth material, the percentage of basal arch width to maximum tooth material, the percentage of basal arch length to maximum tooth material and the percentage of basal arch width plus basal arch length to maximum tooth material were caculated, and then statistical analysis was done. From thie study, the obtained results were as follows; 1. In maxilla, the percentage of basal arch width to maximum tooth material was $46.9{\pm}2.6\%$ in normal occlusion group, $49.4{\pm}3.9\%$ in non-extraction group, and $42.5{\pm}3.3\%$ in extraction group. In mandible, that was $46.6{\pm}2.4\%$ in normal occlusion group, $47.5{\pm}4.0\%$ in non-extraction group, and $42.6{\pm}2.6\%$ in extraction group. 2. In maxilla, the percentage of basal arch length to maximum tooth material was $33.4{\pm}1.9\%$ in normal occlusion group, $33.9{\pm}1.8\%$ in non-extraction group, and $28.7{\pm}2.5\%$ in extraction group. In mandible, that was $34.4{\pm}4.3\%$ in normal occlusion group, $36.5{\pm}1.9\%$ in non-extraction group, and $31.5{\pm}2.5\%$ in extraction group. 3. In maxilla, the percentage of basal arch width plus basal arch length to maximum tooth material was $80.3{\pm}3.4\%$ in normal occlusion group, $83.3{\pm}4.8\%$ in non-extraction group, and $71.2{\pm}4.3\%$ in extraction group. In mandible, that was $81.0{\pm}5.2\%$ in normal occlusion group, $84.0{\pm}5.4\%$ in non-extraction group, and $74.1{\pm}4.1\%$ in extraction group. 4. In Maxilla, the $95\%$ confidence interval of the percentage of basal arch width to maximum tooth material was $46.3-47.5\%$ in normal occlusion group, $48.1-50.7\%$ in non-extraction group, and $41.7-47.2\%$ in extraction group. In mandible, that was $46.1-47.2\%$ in normal occlusion group, $46.1-48.8\%$ in non-extraction group, and $42.0-43.3\%$ in extraction group. 5. In maxilla, the $95\%$ confidence interval of the percentage of basal arch length to maximum tooth material was $32.9-33.9\%$ in normal occlusion group, $33.3-34.5\%$ in non-extraction group, and $28.1-29.2\%$ in extraction group. In mandible, that was $33.4-3.4\%$ in noraml occlusion group, $35.8-37.2\%$ in non-extraction group, and $30.9-33.1\%$ in extraction group. 6. In maxilla, the $95\%$ confidence interval of thepercentage of basel arch width plus basal arch length to maximum tooth material was $79.5-81.0\%$ in normal occlusion group, $81.6-84.9\%$ in non-extraction group, and $70.1-72.2\%$ in extraction group. In mandible, that was $79.8-82.2\%$ in normal occlusion group, $82.1-85.5\%$ in non-extraction group, and $73.1-75.1\%$ in extraction group. 7. There was correlation between maxilla and mandible in the maximum tooth material, the basal arch width, the basal arch length, the percentage of basal arch width to maximum tooth material, the percentage of basal arch length to maximum tooth material and the percentage of basal arch width plus basal arch length to maximum tooth material, but not in the basal arch length of male of the extraction group. * A thesis submitted to the Council of the Graduate School of Kyungpook national University in partial fulfillment of the requirements for the degree of Master of Dental Science in December, 1991.

• The korean journal of orthodontics
• /
• v.25 no.5 s.52
• /
• pp.577-585
• /
• 1995

This study has been performed to determine whether significant differences in the maxillary basal bone pattern exist between skeletal class II malocclusion and normal occlusion. Materials for the skeletal Class III sample consisted of lateral cephalometric roentgenograms and maxillary cast models of 29 adult individuals, 15 males and 14 females. The average age was 19.75 years with a range from 16.4 to 29.1 years. A normal control sample consisted of lateral cephalometric roentgenograms and maxillary cast models of 24 adult individuals, 13 males and 11 females. The average age was 24.25 years with a range from 20.8 to 29.4 years. The results of this study can be summarized and concluded as like follows. 1. In comparing sexual difference of maxillary basal bone morphology in skeletal Class III malocclusion, the following Parameters of males were found to be significally larger than those of females : inter first premolar width, inter molar width, oblique canine height, oblique molar height and maxillary basal bone perimeter. 2. In comparing sexual difference of maxillary basal bone morphology in normal occlusion, the following parameters of males were found to be significally larger than those of females : inter canine width, inter first and second premolar width, inter molar width, oblique canine height and oblique molar height. 3. In comparing maxillary basal bone morphologic difference between skeletal Class III malocclusion md normal occlusion in males, the following parameters were found to be significally larger in normal occlusion : inter canine width, inter canine height, inter molar height, oblique canine height and oblique molar height. 4. In comparing maxillary basal bone morphologic difference between skeletal Class III malocclusion and normal occlusion in females, the following parameters were found to be significally larger in normal occlusion : inter canine height, inter molar height, oblique canine height, oblique molar height and maxillary basal bone perimeter.

• The korean journal of orthodontics
• /
• v.34 no.1 s.102
• /
• pp.93-107
• /
• 2004

Enlow's counterpart analysis explains the complex with anatomic and developmental characteristics where craniofacial aspect of Individuals has been developed. Counterpart analysis does not compare individual measurement with the normal value from the average of majority but analyzes by comparison of values that each individual has. In this study we examined surgical changes in skeletal Class III malocclusion patients(male 40, female 40) and compared them with normal occlusion patients using counterpart analysis. The results indicated that : 1. Skeletal anterior-posterior discrepancy was relieved by shortening of the ramus width(B3). 2. The ramus alignment(R3, R4) was displaced posteriorly and the occlusal plane angle(R5) was rotated clockwise. 3. Skeletal Class III pattern was relieved in the post-operative group, but differences in the level of the cranium(R1, R2) was remaining compared to the normal occlusion patients. 4. In the comparison of surgery methods, the two-jaw surgery group presented changes In the maxillary length(A4), ramus alignment(R3, R4) and occlusal plane angle(R5) compared to the one-jaw surgery group, but the differences were not significant. In the past study about Korean skeletal Class m patients, the skeletal characteristics are upward backward rotation of the cranial base, posterior displacement of the maxilla, forward inclination of the ramus and lengthening of the mandibular body, but in this study, skeletal Class m pattern was relieved by shortening of the ramus width and maxillary advancement by orthognathic surgery, because orthognathic surgery is usually performed on limited areas in the maxilla and the mandible.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.29 no.1
• /
• pp.45-58
• /
• 2013

The purpose of this study was to analyze the area of occlusal contact points using visual method. One subject was selected who had Angle Class I, normal dentition, without dental caries, periodontal disease and temporomandibular disorders. Forty times PVS impressions were taken and 10 pairs casts were fabricated using dental super hard stone. After mounting the casts with customized loading apparatus, 78.9kg/f force was loaded as a maximum biting force. In T-Scan method, occlusal contact points measurement was repeated twice. Then, using Photoshop program (Adobe photoshop CS3, Adobe. San Jose, USA), the pixels which indicated occlusal contact points by color was recognized, and the distribution of recognized pixels were calculated to area. In Add picture method, polyether bite material applied to the occlusal surface of the casts. Then, the image of the translucent areas was recorded and classified $0{\sim}10{\mu}m$, $0{\sim}30{\mu}m$, $0{\sim}60{\mu}m$ area by the amount of transmitted light. To acquire occlusal surface, the numbers of pixels from the photograph of the contact area indicated cast converted to $mm^2$. The mean occlusal contact area by two methods was statistically analyzed (paired t-test). Part of the red and pink area in T-Scan image were almost equivalent to the $0{\sim}10{\mu}m$, $0{\sim}30{\mu}m$, $0{\sim}60{\mu}m$ area in Add picture image. The distribution of occlusal contact points were similar, but the average area of occlusal contact points was wider in T-scan image (P<.05). Pink and red area in T-scan image was wider than $0{\sim}10{\mu}m$, $0{\sim}30{\mu}m$ area in Add picture image (P<.05), but similar to $0{\sim}60{\mu}m$area in Add picture image (P>.05). Occlusal contact points in T-scan image did not indicate real occlusal contact points. Occlusal contact areas in T-scan method were enlarged results comparing with those in Add picture method.

• The korean journal of orthodontics
• /
• v.31 no.3 s.86
• /
• pp.311-323
• /
• 2001

One of the various mechanics used to treat unilateral Class II malocclusion is head gear with asymmetric face bow. We made the finite element models of unilateral Class II maxillary dental arch and power arm asymmetric face bow. We designed this experiment to observe stress distribution of periodontal ligament, reaction force, and displacement and to understand force system, so to predict the therapeutic effect. On the basis of computerized tomograph of maxillary dental arch of 25 years old male with normal occlusion without extraction and orthodontic treatment history, we made finite element models of maxillary dental arch and periodontal ligament. Then we modified that model to unilateral maxillary Class II malocclusion model of which maxillary left molar displaced mesially. Also, We made finite element model of asymmetric face bow of which right outer bow shorter than left by 25mm(RMO, Penta-FormTM/Medium size, 0.045 inch iner bow, 0.072 inch outer bow). After that, retraction force of 250g, 300b, 350g were applied to maxillary first molar. We concluded as follow. 1. The Net force that both maxillary first molars were received increased as the retraction force increased. Mesially positioned tooth received more force than normally positioned tooth. But, both tooth were received distal force, so distal movement occured. 2. Both tooth received buccal lateral force. In analysis of force element, as the retraction force were increased, force of X-axis at mesially positioned tooth decreased, and force of X-axis at normally positioned tooth increased. so lateral force component moved to the side received less force from more force. 3. There were rotation, tipping with distal movement in maxillary first molar. As retraction force were increased, rotation and tipping also increased. More tipping and rotation occured at the side received more force, that is, mesially positioned tooth. Though it Is small change, displacement of same pattern occur in normally positioned tooth

• The korean journal of orthodontics
• /
• v.22 no.3 s.38
• /
• pp.627-646
• /
• 1992

The purpose of this study was to investigate the relationship among the activity of the craniofacial muscle and craniofacial form and occlusal state. In this study, subjects were consisted of 23 male adults with skeletal Class III malocclusion and 30 male adults with normal occlusion. The measurements in oral exam, lateral ceghalogram, and E.M.G. recordings of anterior temporal, masseter, and upper lip muscles at rest position, clenching in centric occlusion, chewing of gum, swallowing of juice, were analyzed with SPSS system. The results were as follows: 1. At rest position upper lip muscle activity of skeletal Class III group was significantly higher than that of normal group. 2. Both clenching and chewing masseter and temporal muscle activity of normal group were significantly higher than that of skeletal Class III group. 3. During swallowing of juice, upper lip muscle activity of skeletal Class III group were significantly higher than that of normal group. 4. The activities of masseter and anterior temporal muscle during clenching and chewing were significantly correlated with hypodivergent facial form and number of occluded teeth. 5. The activity of upper lip during swallowing had positive correlation with mandibular prognathism.

• The korean journal of orthodontics
• /
• v.8 no.1
• /
• pp.59-71
• /
• 1978

The author compared and analysed the roentgenocephalograms of one hundred Korean adults with the normal occlusion (50 males and 50 females), which were taken on the centric occlusion and the rest position of the mandible respectively for every subject, and then researched the relations among the relaxed muscle of the mandible, lightly touched of the lips, and the position just after the swallowing of saliva, of which 38 among 50 males had the rest position of the mandible. The results are as followings: 1. The anterior facial height increases more at the rest position of the mandible than at the centric occlusion, while the posterior facial height decreases. 2. The mandible moves more backward and downward at the rest position of the mandible than at the centric occlusion. 3. The facial procumbency and the incisor tooth inclination increases more at the rest position of the mandible than the centric occlusion in terms of the facial plane. 4. There are no differences between males and females at the rest position of the mandible and the centric occlusion in the meaning of variation. 5. There are no differences among the three methods from the view of lines and angles of the roentgenocephalogram.