• The korean journal of orthodontics
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• v.24 no.1 s.44
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• pp.149-159
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• 1994

The purposes of present study were to evaluate changes in models and lateral cephalometric head films during orthodontic treatment and to compare the amount of incisal retraction and anterior movement of molars with the two approaches of the retraction method of canine(sectional canine retractions vs sliding canine retractions) and the anchorage management(head gears vs no head gears, transpalatal arches vs no transpalatal arches and lingual arches vs no lingual arches) and to evaluate changes during orthodontic treatment in models with relation to lateral cephalometric head films. 67 Korean women with Angle's Class I bialveolar protrusion were selected, whose initial chronologic age was above 16 yrs. Models and lateral cephalometric head films were taken before and after orthodontic treatment with four bicuspid extraction. the results were obtained as follows. 1. Significant decreases were observed in intermolar width, arch length and arch perimeter of maxilla and mandible but significant difference was not observed in intercanine width of maxilla and mandible during treatment period. 2. The linear change of the upper incisor to upper lip was 2.84:1 and the linear change of the lower incisor to lower lip was 1.45:1 3. There were no significant differences between the two groups(sectional canine retractions vs sliding canine retractions), the !we groups(transpalatal arches vs no transpalatal arches) and the two groups(lingual arches vs no lingual arches) in the amount of incisal retraction and anterior movement of molars. There were a greater amount of maxillary incisal retraction and a lesser amount of anterior movement of maxillary molars with the use of head gears than no use of head gears. 4. Changes during orthodontic treatment in models with relation to lateral cephalometric head films were obtained as follows : 1) Maxilla Central incisors were moved 3.79mm backward, canines were moved 0.22mm laterally and 3.70mm backward, and molars were moved 0.535mm medially and 2.29mm forward. 2) Mandible Central incisors were moved 3.04mm backward, canines were moved 0.145mm laterally and 3.92mm backward, and molars were moved 0.755mm medially and 1.77mm forward.

• The korean journal of orthodontics
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• v.22 no.3 s.38
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• pp.691-701
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• 1992

Over recent 20 years, with socioeconomic development and change of recognition of the population, more people are concerned about their health and appearance. To obtain the change of frequency of malocclusion and the demand for orthodontic treatment, with this trend, 2460 freshmen and students of Yonsei Univ. in 1991, aged from 18 to 21 were examined excluding 187 students who have history of orthodontic treatment, 86 students who are undergoing treatment, 39 students who have too much missing teeth to classify. After analize the frequency of malocclusion and the demand for orthodontic treatment, following results was obtained. 1. Sex ratio in the prevalence of malocclusion was $91.7\%/90.8\%$, male to female, so there was no sex predilection. 2. With regard to Angle's Classification, each percentage of Class I, Class II div. 1, Class II div. 2 and Class III was $61.6\%,\;11.3\%,\;1.9\%\;and\;16.7\%$. 3. Of Class I malocclusion, percentage of crowding was 53.2, this occupied the largest part of single findings and prevalent findings in combinations were also crowding - crossbite and crowding - Protrusion. 4. Of Class I malocclusion, over the portion of$95\%$, Bialveolar Protrusion have arised alone. 5. The distribution of Demands for orthodontic treatment of malocclusion were $41.3\%$ in males, and $51.3\%$ in females.

• The korean journal of orthodontics
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• v.34 no.5 s.106
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• pp.458-464
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• 2004

Anchorage plays an important role in orthodontic treatment especially in the maxillary arch. In spite of many efforts for anchorage control. it was difficult for clinicians to predict the result of treatment because most of the treatment necessitated an absolute compliance of patients, But recently, skeletal anchorage has been used widely because it does not necessitate patient compliance but produces absolute anchorage. In addition titanium miniscrews have several advantages such as ease of insertion and removal. possible immediate leading and use in limited implantation spaces. In this case, a skeletal Class I bialveolar protrusion Patient was treated with standard edgewise mechanics using indirect active P.S.A. (palatal skeletal anchorage). The miniscrews in the paramedian area of the hard palate provided anchorage for retraction of the upper anterior teeth and remained firm and stable throughout treatment This indicates that the PSA can be used to reinforce anchorage for orthodontic treatment in the maxillary arch Consequently, this new approach can help effective tooth movement without patient compliance, when used with various transpalatal arch systems.

• Journal of Korean Dental Science
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• v.7 no.2
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• pp.66-79
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• 2014

Purpose: To analyze the amount and pattern of tooth movement and the changes in arch dimension of mandibular dentition after orthodontic treatment using a new three-dimensional (3D)-indirect superimposition method. Materials and Methods: The samples consisted of fifteen adult patients with class I bialveolar protrusion and minimal anterior crowding, treated by extraction of four first premolars with conventional sliding mechanics. After superimposition of 3D-virtual maxillary models before and after treatment using best-fit method, 3D-virtual mandibular model at each stage was placed into a common coordinate of superimposition using 3D-bite information, which resulted in 3D-indirect superimposition for mandibular dentition. The changes in mandibular dental and arch dimensional variables were measured with Rapidform 2006 (INUS Technology). Paired t-test was used for statistical analysis. Result: The anterior teeth moved backward, displaced laterally, and inclined lingually. The posterior teeth showed statistically significant contraction toward midsagittal plane. The amounts of backward movement of anterior teeth and forward movement of posterior teeth showed a ratio of 6 : 1. Although the inter-canine width increased slightly (0.8 mm, P<0.05), the inter-second premolar, inter-first molar, and inter-second molar widths decreased significantly with similar amounts (2.2 mm, P<0.05; 2.3 mm, P<0.01; 2.3 mm, P<0.001). The molar depth decreased (6.7 mm, P<0.001) but canine depth did not change. Conclusion: A new 3D-indirect superimposition of the mandibular dentitions using best-fit method and 3D-bite information can present a guideline for virtual treatment planning in terms of tooth position and arch dimension.