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

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

In the past, the jaw and occlusal relationship in centric occlusion were merely considered in case of orthodontic diagnosis and treatment planning. As the fact that functional disturbance of the temporomandibular joint may be caused by occlusal interference was recognized, the importance of functional occlusion and centric relation is emphasized today. Known the importance of centric relation, there are various opinions about definition of centric relation and its taking methods. The purpose of this study was to investigate the relative centric condyle position and to compare the reproducibility of the recordings utilizing different centric relation records obtained by different taking methods. The 15 adults with normal occlusion were participated in this study. Every four centric relation records were taken in each of three methods - leaf gauge, Dawson and myomonitor method. Then the relative centric condyle position, the distance between the condylar position in centric occlusion and the position in centric relation and the reproducibility were studied using SAM 2 articulator and mandibular position indicator. The results were as follows; 1. The trend of condyle position was different depending on centric relation taking methods. 2. The position of condyle in centric relation by leaf gauge and Dawson methods was superior to that by myomonitor method, and the position by myomonitor method was relatively antero-inferior. 3. The distance between the condylar positions in centric occlusion and the position in centric relation was longest in myomonitor method. 4. The reproducibility had little differences in transverse direction among three methods, while leaf gauge method showed the highest reproducibility and myomonitor method did the lowest reproducibility in antero-posterior and supero-inferior direction.
Adult ; Centric Relation* ; Dental Articulators ; Diagnosis ; Humans ; Jaw ; Mandibular Condyle* ; Temporomandibular Joint

The purpose of this study was to evaluate the availability of computer system for the measurement of tooth size in the model analysis through the comparison of two measurements: One was to use a computer; and the other was to use vernier calipers. Twenty sets of casts were used, which showed a moderate degree of crowding and full eruption of all teeth. The mesio-distal width of 12 teeth from the left central incisor to the left first molar at each set of the casts were measured twice with vernier calipers and a computer respectively. This measurement was repeated two weeks later. First, for the reproducibility analysis, the two computer measurements were compared then the vernier calipers measurements were compared. Second, all the teeth were sepapated into the region of mesiodistal contact points and its width was measured by a micrometer to obtain standard measurements. For the accuracy analysis, these standard measurements were compared with the measurements from the dental casts using two methods. The difference between them was defined as the measurement error. To investigate the cause of measurement error, an examination was made for the presence and degree of contact point deviation on each tooth from the upper and lower occlusograms, and the mesio-distal angulation of each tooth was measured with TARG. Following results were obtained through statistical analysis. 1. In the analysis for reproducibility ; the measurements with vernier calipers showed significant differences in three out of twelve teeth while the computer measurements showed significant differences in one out of twelve teeth. 2. In the analysis for accuracy : compared with the standard measurements, the measurements with vernier calipers showed significant differences in three out of twelve teeth while the compute measurements showed significant differences in two out of twelve teeth. 3. Compared with the standard measurements. the measurements with vernier calipers were apt to be larger at the upper first molar, and smaller at the lower first molar. The computer measurements, however, were apt to be larger at both upper and lower first molars. 4. the measurements with vernier calipers showed the largest error at the lowe first molar and the degree of error was variable according to the tooth while the difference of error was small in the computer measurements. 5. In the analysis for the correlation of the degree of measurement errors with the contact point deviation index and the mesio-distal crown angulation of each tooth, the measurements with vernier calipers did not show significant correlation while th measurements with computer showed slight positive correlations. The results of this study indicate that a computer system may be useful for the measurement of tooth size in the model analysis.
Computer Systems ; Crowding ; Crowns ; Incisor ; Molar ; Tooth*

The purpose of this study was to evaluate the effect of splinting methods on the rearrangement of periodontal fibers after experimental tooth movement. Orthodontic force was applied by placing closed coil spring between upper third incisor and canine in seven dogs, weighing 20kg or more. After 3 weeks of force application, 0.025 inch multistrand wire and polyethylene ribbon were bomded to each side, as a flexible and rigid splinting respectively in 6 experimental animals. The remaining one served as a control. Each two animals were sacificed at 4, 8 and 12 weeks after splinting respevticvely and prepared histologically for hematoxylin-eosin and Masson';s trichrome staining. The results of this study were odtained follows: 1. After tooth mocement, periodontal space was narrowed and periodontal fibers were thick on pressure side while elongated fibers were observed on tension side. 2. After 4 weeks of retention, the rearrangement of periodontal fibers was observed in the flexible splinting group, but not in the rigrd splinting group. 3. After 8 weeks of retention, the rearrangement of periodontal fivers was obwerved in both groups, but the difference could not be detected between two groups. 4. During the retention period, the rearrangement of periodintal fibers was faster in tension side than in pressure side. There results show that the rearrangement of periodontal fibers is also obtained by rigid splinting after tooth movement. It is suggested that the rigid splinting by polyethylene ribbon can be used as way of postorthodontic retention.
Adult* ; Animals ; Dogs* ; Humans ; Incisor ; Polyethylene ; Splints* ; Tooth Movement* ; Tooth*

If the centric prematurity occurs after orthodontic treatment, it creates centric slide regarded as a possible factor in the cause of temporomandibular disorder and/or postorthodontic relapse. The purpose of this study was to investigate the manner of centric prematurity and centric slide in postorthodontic patients. The 36 orthodontic patients who had been treated with edgewise appliance at least 3 months previously were used in this study. After recording centric relation by the leaf gauge technique, the centric prematurity and centric slide were studied using SAM2 articulator and mandibular position indicator. The results were as follows: 1. The highest percentage of centric prematurities were found on the second molars. 2. The buceal incline of the palatal cusp was the most frequent area of centric prematurities in the maxilla, while the lingual incline of the buccal cusp was the most frequent area in the mandible. 3. There were no trends in the direction of centric slide on the mandibular position indicator. 4. There were no significant differences in centric discrepancies between the premolar extraction and nonextraction group.
Bicuspid ; Centric Relation ; Dental Articulators ; Humans ; Mandible ; Maxilla ; Molar ; Recurrence ; Temporomandibular Joint Disorders

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