A treatment should be functional, esthetic, conservative and periodontally healthy in order to meet criteria of an ideal dental procedure. in a prsthodontic patient with horizontal and/or vertical space deficiency, orthodontic tooth movement should be considered as a pre-prosthetic procedure. With a conventional technique, orthodontic treatment is a time-consuming and uncomfortable procedure. Pre-prosthetic orthodontic treatment, however, is no longer difficult procedure with the help of recently developed techniques, such as passive bracketing. The present article outlines the problems and causes of horizontal and vertical space deficiency in prosthodontic patients, and presents efficient pre-prosthetic orthodontic treatment modalities with typical clinical cases.
Humans ; Prosthodontics* ; Tooth Movement

With conventional orthodontics, it was difficult for the anchorage segments of the wire to be engaged passively in the brackets even with complicated bending. To overcome this limitation, a kind of indirect bonding, "passive bracketing", has been developed. The present article shows laboratory and clinical procedures of the passive bracketing
Orthodontics*

No abstract available.
Child* ; Humans

We tend to consider only static occlusion such as molar relationship, canine key, and interdigitation at finishing stage. Of course, this static occlusion is important for post-orthodontic stability. But we should remember that mandible is always on the move during its various functions. If no pressure or too much pressure is put on during its functions, untoward tooth movement could occur. And tooth mobility, periodontitis, wear facet, bruxism, and far worse temporomandibular disorder could occur. After many studies have been done on what is a desirable occlusal scheme to strengthen post-orthodontic stability t today, "mutually protective occlusion" is recommended. If an orthodontist does not have understanding about this occlusal scheme during orthodontic treatment, the following conditions will be resulted after orthodontic treatment. I. Centric discrepancy 1. centric prematurity 2. sunday bite 3. molar fulcrum II. Eccentric discrepancy 1. posterior interference 2. anterior interference If we have deep understanding about these discrepancies that can happen after orthodontic treatment and their causes, corrections, and especially preventions against them, post-orthodontic stability could be strengthened and further temporomandibular disorder could be prevented.
Bruxism ; Mandible ; Molar ; Periodontitis ; Temporomandibular Joint Disorders ; Tooth Mobility ; Tooth Movement

Recently, magnetic forces are considered as a method for more efficient tooth movement. The purpose of this study was to evaluate the effects of the changes of the magnetic volume on the magnetic forces. The universal testing machine and the electronic balance were used for the exact measurement of the force with constant air gap. While the magnet was kept same on one side, the magnetic volume of the other side was increased gradually in four manners. In the first group, the thickness was increased by adding same size of the magnets one after another while the thickness was increased by changing with a thicker magnet gradually in the second group. In the third group, the width was increased by adding same size of the magnets while the width was increased by changing with a wider magnet gradually in the last group. The results were as follows: 1. With the increase of the thickness, the magnetic force increased, while the magnetic force decreased with the increase of the width. 2. The magnetic force according to the change of the magnetic volume showed the distribution of the logarithmic function. 3. An originally thick magnet showed larger force tharr the added magnets although both of them had same volume.
Tooth Movement

This study was performed to compare and analyzed the mode of tooth movement according to the timing of orthodontic force application after extraction. The upper right and left third incisors were carefully extracted at three-week interval in four adult dogs. Both canines were used as an anchorage for the bodily movement of the upper second incisors. Orthodontic force of 100gm was simultaneously applied at one week after extraction on one side four weeks after extraction on the other side using NiTi closed coil spring. While orthodontic force was applied for twelve weeks, the amount of tooth movement was measured at every second week with calipers. The animals were sacrificed at twelve weeks and histologic examination was executed to reveal any difference between both sides. The results were obtained as follows: 1. The tooth movement was likely to be faster in four-week side for the first two seeks while faster in one-week side during next two weeks 2. The rate of tooth movement was fastest during four to six weeks period, then decreased gradually. 3. The total amount of tooth movement was likely to be larger in one-week side compared to four-week side. 4 Any damage to tooth and periodontal tissue could not be seen in the histologic section of one-week side. These results suggest that earlier application of orthodontic force is better than later after extraction in terms of the rate of tooth movement.
Adult ; Animals ; Dogs ; Humans ; Incisor ; Tooth Movement* ; Tooth*

OBJECTIVE: With an increasing demand for esthetic orthodontic appliances, the interest in polycarbonate brackets has also increased. However, polycarbonate bracket wings are prone to fracture. The purpose of this study was to evaluate the clinical usefulness of a newly-developed polycarbonate bracket by measuring the fracture strength of bracket tie wings. METHODS: Alice (K.M. Daicom, Seoul, Korea) and Spirit MB (Ormco, Glendora, CA, USA) brackets were used as an experimental and control bracket respectively. Each bracket group was divided into halves. One half was untreated and the other half was treated with 2,000 times of thermocycling between 5 degrees C and 55 degrees C. The fracture strength of the wing was measured by a universal testing machine. RESULTS: Alice bracket wings showed significantly higher strength than Spirit MB bracket wings in both untreated and thermocycled bracket cases. CONCLUSION: Alice brackets may be used clinically in terms of the strength of bracket wings.
Orthodontic Appliances ; Seoul

Translational movement along an arch wire requires sufficient force to overcome frictional forces between bracket and arch wire. The orthodontist must appreciate the importance of friction in this process, and study out the influencing factors on the level of friction. The purpose of this study was to evaluate the effect of artificial saliva on frictional resistances generated between the bracket and arch wire. Independent variables of this study were arch wire material, angulation and environment. Static frictional forces of cobalt-chromium, heat-treated cobalt-chromium, beta-titanium, stainless steel wires were measured under non-angulated dry, angulated dry, non-angulated saliva, angulated saliva conditions. The results were as follows : 1. Stainless steel wires showed lower friction values in non-angulated dry condition, and heat-treated cobalt-chromium wires showed higher friction values in angulated dry condition. Higher friction values were showed in order of cobalt-chromium, stainless steel, heat-treated cobalt-chromium and beta-titanium wires in non-angulated saliva condition, and were showed in order of stainless steel, cobalt-chromium, heat-treated cobalt-chromium, beta-titanium wires in angulated saliva condition. 2. Angulation increased friction for stainless steel wires under dry condition. 3. Artificial saliva decreased friction for cobalt-chromium wires and increased friction for stainless steel wires under non-angulated condition. 4. Artificial saliva decreased friction for all wires except beta-titanium wires under angulated condition. 5. Regardless of angulation or environment, heat-treated cobalt-chromium and beta-titanium wires showed higher friction values, and stainless steel wires showed lower friction values.
Friction* ; Orthodontic Wires* ; Saliva ; Saliva, Artificial* ; Stainless Steel

This study was concerned with comparing the measured values of labial alveolar bone through the lateral cephalometric radiography and mandibular incisor cross-secional tomogram between two groups, one group of mandibular prognathism patients who needed an orthognathic surgery as an experimental group and the other group who had normal relationships as a control group. The purpose of the study was to find out the predisposing factors of bone resorption and gingival recession before orthodontic treatment. The results were as follows: 1. The cross-sectional area of labial alveolar bony plate in mandibular prognathism was significantly smaller than that of control group. 2. In mandibular prognathism, the distance between cementoenamel junction and aveolar crest was significantly greater than control group. 3. There were negative correlations between area of labial alveolar bony plate and distance from cementoenamel junction to alveolar crest, and positive correlations between area of labial alveolar bony plate and distance from alveolar crest to root apex. 4. In mandibular prognathism, there were positive correlations between IMPA and thickness of symphysis, and negative correlations between IMPA and the alveolar bony height. The results of the present study suggest the mandibular prognathism patients are prone to the gingival recession due to the small amount of labial alveolar bone around lower incisors.
Bone Resorption ; Causality ; Gingival Recession ; Humans ; Incisor* ; Orthognathic Surgery ; Prognathism* ; Radiography ; Tooth Cervix

The purpose of this study was to evaluate the effect of oral environment on the strength of resin bracket wings by comparing fracture mode according to water immersion and thermocycling. Seventy-five resin brackets(Spirit MB, Ormco, California) were divided into three groups and treated for six months as follows; (1) untreated, (2) water immersion in distilled water at 37degrees C, (3) water immersion in distilled water at 37degrees C with total 2,100 times of thermocyeling taken 350 times each month. Fracture mode of the wing was tested on universal testing machine. In addition to resin brackets, 25 metal brackets were used as controls. Through the statistical analyses, following results were obtained. 1. Resin bracket wings showed significantly lower fracture strength than metal brackets(p<0.001). 2. Water immersion and water immersion with thermocycling groups showed significantly lower fracture strength than open air condition group(p<0.001). 3. Water immersion with thermocycling group showed significantly lower fracture strength than water immersion group(p<0.001). The above results sugg est that the mechanical property of resin bracket wing may be influenced by oral environment and further research is needed to improve the strength of the wing in the resin bracket.
Immersion* ; Water*