• The korean journal of orthodontics
• /
• v.35 no.5 s.112
• /
• pp.331-340
• /
• 2005

Angulation and inclination of clinical crown is important for diagnosing, treatment planning and developing convenient orthodontic attachments. The aim of the study was to establish normative data with higher reliability on the angulation and inclination of clinical crown of Koreans with normal occlusion This study employed the dental casts of 307 (male. 187: female. 120) adult normal occlusion samples. The angulation and inclination of clinical crown were measured by set-up model checker In order to ensure reliability, intra- and inter-rater error were evaluated 3 times The resultant data obtained had excellent reliability however when compared with the previous data as well as with gender difference, clinically significant interpretation was impossible because the whithin-dataset normal variation was High which was common pattern of angulation and inclination measuring data of previous research The result of this biometric study seemed 4o suggest more substantive design of the multivariate. high-dimensional interpretation methodology of these normal variation is required if more compatible orthodontic appliance could be developed.

• The korean journal of orthodontics
• /
• v.34 no.6 s.107
• /
• pp.473-480
• /
• 2004

The aim of this study was to establish normative data on the tooth size and arch parameters of Koreans with normal occlusion, This study employed the dental casts of 296 (male: 179; female 117) normal occlusion samples, who were selected from 15,836 adults through a community dental health survey. The mesiodistal diameters of teeth, arch width, and arch length were measured by digital electronic calipers(accurate to 0.01 mm) and Bolton's indices as well as intermaxillary arch width ratios were calculated. In order to ensure reliability, intra- and inter-examiner error were evaluated. Although our dimensional data showed overt differences between genders, the indices and intermaxillary ratios evaluated were the same. The resultant data obtained were compared with the previous data to reveal whether any changes have occurred over the time. The clinical implication of the present findings was also discussed. This biometric study seemed to provide a clinically applicable diagnostic criteria for an individual malocclusion patient.

• The korean journal of orthodontics
• /
• v.29 no.5 s.76
• /
• pp.575-587
• /
• 1999

This study was designed to evaluate the correlations between tongue with skeletal pattern and intermaxillary space in Class II malocclusion adult patients. Craniofacial skeletal pattern was analyzed on the lateral cephalometric radiograph and the subjects were devided two groups by facial ratio, the 30 subjects of hyperdivergent group and the 30 subjects of hypodivergent group. The size and posture of tongue and intermaxillary space were measured on the lateral cephalometric radiograph. These data were statistically analyzed to examine significant differences between both groups and compared the correlation between tongue with skeletal measurements and intermaxillary space in each group. The results of this study were as follows. 1. In comparison of the tongue and intermaxillary space, the measurement of TS/IS showed significantly larger in hyperdivergent group and PIH and IS showed significantly larger in hypodivergent group. There were no statistically significant differences in the measurements of the height and posture of tongue. 2. In correlation between tongue with craniofacial skeletal measurements, the length and height of tongue showed the highest correlation with AFH(anterior facial height) in both groups(p<0.01). And that measurements showed high correlation with PFH(posterior facial height) in hypodivergent group. 3. In both groups, most measurements of tongue showed high correlation with intermaxillary space and the height and space of tongue showed high correlation with AIH and PIH(p<0.01).

• The korean journal of orthodontics
• /
• v.19 no.2
• /
• pp.130-143
• /
• 1989

The purpose of this study was to assess the early effect of FR III on the growing patients with anterior cross-bite. The lateral cephalograms and models were obtained from 7 patients at the time of pretreatment and correction of anterior cross-bite. The results were as follows: 1. A slight tendency of rotation toward anterosuperior direction and the growth to anterior direction were shown in maxilla. 2. There were a little change of mandibular vertical position and increase in lower facial height although some variations existed. 3. The bodily or labial tipping movement was shown in maxillary incisors. 4. The lingual tipping of mandibular incisors was shown in all cases. 5. Maxillary arch width increased while mandibular arch width usually changed a little although some variations existed. But it was difficult to summary in a word because variable responses were noted according to a wide variety of skeletal type, growth, and malocclusion.

• Journal of Oral Medicine and Pain
• /
• v.33 no.2
• /
• pp.121-132
• /
• 2008

To establish the diagnosis and treatment plan for skeletal Class II malocclusion, patient's skeletal morphology, prognosis as well as the treatment effect is one of the important factor to consider. Therefore, the present study classified analyzed the difference between initial(T1) and after use of activator(T2), and after finish of direct multi-bonding system treatment(T3) for Class II malocclusion during growth period according to the treatment result(effective body length) and morphology of vertical skeletal type. The experimental group was classified into two groups(1 group, 2 group) according to the effective body length change between before and after use of activator, showed good treatment effect of activator for patient with small mandible and large differential between maxilla and mandible, and short anterior facial height. And the difference between 1 and 2 group in the experimental group before treatment(T1) disappeared in the finished treatment(T3). But in contrast, the initial difference of T1 stage between a and b group in the control group did not disappear in the finished treatment(T3). In short, experimental group's treatment effect was much better than contrast group and the treatment effect was maintained and got stable results at comparison experimental group with contrast group. Through this study, we can find activator's treatment effect and stable retention of that in growing Class II malocclusion patients. By estimate of activator treatment effect through these results, we can establish the correct diagnosis and treatment plan for adolescent Class II malocclusion estimate of activator treatment effect and lead the ideal facial growth pattern.

• The korean journal of orthodontics
• /
• v.36 no.5
• /
• pp.369-379
• /
• 2006

Objective: The purpose of this study was to find changes in the occlusal plane related to different vertical facial patterns and suggest treatment goals and conduct possible treatment mechanisms. Methods: 60 adult patients (28 males, 32 females) who had been diagnosed as Class 1 skeletal malocclusion and treated without extraction were selected. Patients were divided into three groups; short face type (group 1), average face type (group 2) and long face type (group 3), using the data on normal occlusion of Korean adults. Results: The results were achieved by analyzing cephalometric tracings of each group at pre-treatment, end-treatment and post-treatment (about 1 year recall check). The inclination of the occlusion plane tends to gradually increase as the face becomes longer In group 1, COP-X, FOP-X, L6/L1, MP-L6 were significantly decreased, and L1-FOP was significantly increased during the retention period (T3-T2). Group 2 showed no significant change, In group 3, FOP-X was significantly increased during the retention period (T3-T2). During the retention period, FOP-X showed significant change among each group, especially between group 1 and group 3. Conclusion: These results suggest that changes of occlusal plane inclination according to facial vertical pattern need to be considered during the retention period for intrusion, extrusion, and incisor overbite.

• The korean journal of orthodontics
• /
• v.18 no.1 s.25
• /
• pp.89-104
• /
• 1988

This study was performed to investigate the relationships between the EMG activity of the masticatory muscles in Angle's Class II div. 1 malocclusion and normal occlusion. This study was ranged from age 12 to 14 year-old for 30 male subjects: 15 subjects were Angle's Class II div. 1 malocclusion, and 15 subjects were normal occlusion with acceptable profile. Their cephalometric measurement were analyzed, and the EMG recordings from the anterior temporal, posterior temporal, masseter, and orbicularis oris muscles were analyzed during rest position, mastication of peanuts, and swallowing. All data was recorded and statistically processed with the VAX-11/780 computer system. The results were as follows: 1. The activity of muscles at rest was highest in the posterior temporal muscle with normal occlusion, as well as in those with Class II div. 1 malocclusion, and the posterior temporal muscle activity of Class II div. 1 malocclusion was higher than that of normal occlusion. 2. During mastication, all muscle activities of Class II div. 1 malocclusion were recorded lower than those of normal occlusion, and the activity of the anterior temporal muscle was higher than that of the posterior temporal muscle in both types of occlusion. 3. As for the activity in orbicularis oris muscle, it was greater in opening phase than in closing phase during chewing cycle with both types of occlusion. 4. During swallowing, the activities of the anterior temporal, masseter, and orbicularis oris muscles of Class II div. 1 malocclusion were recorded lower than those of normal occlusion.

• The Journal of the Korea Contents Association
• /
• v.21 no.8
• /
• pp.258-270
• /
• 2021

This study aimed to investigate the effects of the virtual reality simulation for malocclusion examination for dental education. A 4-step modeling procedure was applied to develop a tooth model with a realistic level in order to be held and observed in detail. Eighty-six participants used HMDs to examine the developed virtual dental simulation to identify their perception according to expertise levels. The independent variable, expertise group, included three levels: 29 juniors, 29 seniors, and 28 dentists, respectively. The dependent variables, that were task-load and usability, were measured through two cases. Results showed that the junior group perceived a higher level of mental demands and embarrassment than the dentist group. It indicated that the perceived task load varies according to the expertise levels in the simulation task. However, the senior group perceived a higher level of ease of use than the dentist group. This study presented the implications for the development of virtual reality simulation in detail.

• 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.23 no.1 s.40
• /
• pp.101-113
• /
• 1993

For the purpose of interpretation of positional changes of craniofacial structures in Class III malocclusion between mixed and permanent dentition, 73 normal samples and 103 Class III samples of mixed dentition and 125 normal samples and 168 Class III samples of permanent dentition were selected. Comparative cephalometric analysis was undertaken between them respectively by mesh diagram method to evaluate the positional changes of maxilla and mandible in anteroposterior direction and vertical direction and also the inclination changes of maxillary and mandibular incisors in labio-lingual direction. The following results were obtained : 1. The antero-posterior positional changes of the maxilla and mandible were posterior direction of maxilla and anterior direction of mandible. 2. The vertical positional changes of the maxilla and mandible were superior direction of both maxilla and mandible. 3. The labio-lingual inclination changes of the maxillary and mandibular incisors were lingual direction of both maxillary and mandibular incisors.