• The korean journal of orthodontics
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• v.31 no.2 s.85
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• pp.209-223
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• 2001

At intrusion of upper anterior teeth in patient with periodontal defect, the use of three-piece base arch appliance for pure intrusion is required. To investigate the change of the center of resistance and of the distal traction force according to alveolar bone height at intrusion of upper anterior teeth using this appliance, three-dimensional finite element models of upper six anterior teeth, periodontal ligament and alveolar bone were constructed. At intrusion of upper anterior teeth by three-piece base arch appliance, the following conclusions were drawn to the locations of the center of resistance according to the number of teeth, the change of distal traction force for pure intrusion and the correlation to the change of vertical, horizontal location of the center of resistance according to alveolar bone loss. 1. When the axial inclination and alveolar bone height were normal, the anteroposterior locations of center of resistance of upper anterior teeth according to the number of teeth contained were as follows : 1) In 2 anterior teeth group, the center of located in the mesial 1/3 area of lateral incisor bracket. 2) In 4 anterior teeth group. the center of resistance was located in the distal 2/3 of the distance between the bracket of lateral incisor and canine. 3) In 6 anterior teeth group, the center of resistance was located in the central area of first premolar bracket .4) As the number of teeth contained in anterior teeth group increased, the center of resistance shifted to the distal side. 2. When the alveolar bone height was normal, the anteroposterior position of the point of application of the intrusive force was the same position or a bit forward position of the center of resistance at application of distal traction force for pure intrusion. 3. When intrusion force and the point of application of the intrusive force were fixed, the changes of distal traction force for pure intrusion according to alveolar bon loss were as follows :1) Regardless of the alveolar bone loss, the distal traction force of 2, 4 anterior teeth groups were lower than that of 6 anterior teeth group. 2) As the alveolar bone loss increased, the distal traction forces of each teeth group were increased. 4. The correlations of the vertical, horizontal locations of the center of resistance according to maxillary anterior teeth groups and the alveolar bone height were as follows : 1) In 2 anterior teeth group, the horizontal position displacement to the vortical position displacement of the center of resistance according to the alveolar bone loss was the largest. As the number of teeth increased, the horizontal position displacement to the vertical position displacement of the center of resistance according to the alveolar bone loss showed a tendency to decrease. 2) As the alveolar bone loss increased, the horizontal position displacement to the vertical position displacement of the center of resistance regardless of the number of teeth was increased.

• The korean journal of orthodontics
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• v.32 no.6 s.95
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• pp.443-453
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• 2002

The principal aims of this study were to identify the composition of salivary pellicles formed on various orthodontic brackets and to obtain a detailed information about the protein adsorption profiles from whole saliva and two major glandular salivas. Four different types of orthodontic brackets were used. All were upper bicuspid brackets with a $022{\times}028$ slot Roth prescription; stainless steel metal, monocrystalline sapphire, polycrystalline alumina, and plastic brackets. Bracket pelicles were formed by the incubation of orthodontic brackets with whole saliva, submandibular-sublingual saliva, and parotid saliva for 2 hours. The bracket pellicles were extracted and confirmed by employing sodium dodecyl sulfatepolyacrylamide gel electrophoresis, Western transfer methods, and immunodetection. The results showed that low-molecular weight salivary mucin, ${\alpha}-amylase$, secretory IgA (sIgA), acidic proline-rich proteins, and cystatins were attached to all of these brackets regardless of the bracket types. High-molecular weight mucin, which promotes the adhesion of Streptococcus mutans, did not adhere to uy orthodontic brackets. Though the same components were detected in all bracket pellicles, however, the gel profiles showed qualitatively and quantitatively different pellicles, according to the origins of saliva and the bracket types. In particular, the binding of sIgA was more prominent in the pellicles from parotid saliva and the binding of cystatins was prominent in the pellicles from the form plastic brackets. This study indicates that numerous salivary proteins adhere to the orthodontic brackets and these salivary proteins adhere selectively according to bracket types and the types of the saliva.

• The korean journal of orthodontics
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• v.30 no.1 s.78
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• pp.83-89
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• 2000

The purposes of this study were to evaluate clinical applicability of resin modified glass ionomer cements and to determine the effect of salivary contamination on the tensile bond strength. Fourty extracted human permanent premolars were prepared lot bonding and standard edgewise brackets were bonded with Ortho-One, Fuji Ortho LC, Vitremer and Advance. Fourty extracted human permanent premolars were contaminated with saliva, dried and bonded with same materials above. The tensile bond strength was tested by Instron testing device aster storage in normal saline at ,$37^{\circ}C$ for 24 hours from bonding. The results were as follows : 1. The tensile bond strength of Ortho-One group was $7.68\pm1.76$, Advance group was $7.87\pm2.80$, Fuji Ortho LC group was $4.99\pm2.53$, Vitremer group was $2.80\pm0.88$ MPa. The tensile bond strength in contaminated condition of Ortho-One group was $4.12\pm1.67$, Advance group was $5.37\pm0.68$, Fuji Ortho LC group was $4.41\pm1.61$, Vitremer group was $2.60\pm1.10$ Mpa. 2. Salivary contamination did not affect the tensile bond strength when compared with the uncontaminated enamel group in Fuji Ortho LC and Vitremer (p>0.05) and there was great significant difference in the tensile bond strength of Ortho-One and Advance. 3. Advance, Ortho-One and Fuji Ortho LC seemed to have clinically a proper bond strength.

• The korean journal of orthodontics
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• v.36 no.4
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• pp.308-320
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• 2006

Rapid canine retraction, first introduced by Liou, is a distraction osteogenesis applied to the periodontal ligament tissue. Rapid tooth movement was facilitated by establishing minimal bony resistance on the distal surface of the canine by socket preparation and by osteogenesis on the mesial side in response to the periodontal distraction. Since undesired buccal tipping or extrusion of the canine during retraction tends to occur, it is crucial to maintain the firm path of movement and the axis of the canine during retraction. In order to improve the predictability of the canine movement, lingually extended distraction screws with heavy labial guiding wires were designed. Prefabricated plastic canine models for the estimation of socket depth and miniscrew implants for anchorage reinforcement were also devised. Applying these devices to a female patient with Class II anterior protrusion, the whole treatment was effectively finished in 13 months. Loss of vitality or periodontal problems did not occur throughout treatment, and stable occlusion was maintained during 10 months of retention. This case report demonstrates that a predictable rapid canine retraction can be achieved through the use of this modified technique.

• The korean journal of orthodontics
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• v.34 no.1 s.102
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• pp.83-91
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• 2004

This study was performed to examine treatment efficiency and patient discomfort rate according to used handpiece speed in clean-up technique. Brackets were bonded to extracted human premolar(50 teeth). After debonding, 50 extracted human premolar were divided Into each two groups(low speed handpiece group with tungsten carbide bur and high speed handpiece group with ultra-fine diamond finishing bur) of 25 according to used handpiece speed in clean-up technique. In clean-up procedure, teeth vibration and pulp thermal changes were measured. After clean-up procedure, the enamel surfaces of randomly selected 10 teeth from each two groups were taken by SEM and evaluated. The findings of this study were as follows ; 1. During resin removal, tooth vibrations of various amplitude in low speed handpiece group were more than those of high speed handpiece. 2. The pulpal thermal changes of high speed handpiece group were significantly higher than those of low speed handpiece group, also the resin removal time in high speed handpiece group was almost as twice as in low speed handpiece group. 3. The figures of SEM to enamel surfaces after resin removal showed that notches and resin remnants in high speed handpiece group were more than those in low speed handpiece group.

• The korean journal of orthodontics
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• v.26 no.4
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• pp.441-447
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• 1996

This study was carried out in order to find out the pattern of the root resorption following maxillary incisor retraction after maxillary 1st bicuspid extration in maxillary protrusion patients. For this study, thirty two patient who received orthodontic treatment were chosen. The results were as follows; 1. Of the total 192 teeth, 61 teeth(31.77%) showed no apical root loss, 64 teeth(33.33%) fell into the class "slight", 46 teeth(23.96%) fell into the class "moderate". Only 21 teeth(10.94%) were classified as "excessive". 2. No correlation was noted between the amount of apical root loss and the types of tooth movement of the maxillary central incisors. 3. The patients who were treated with standard brackets had more changes in tooth axis and less movement of root apexes, but the patients with straight brackets had less changes in tooth axis and more movement of root apexes. 4. Comparing the degree of root resorption between bracket types, patients who had used standard brackets showed more apical root loss than patients who had used straight brackets. 5. The most frequent degree of root resorption observed in standard bracket patients was second degree, followed by first degree and third degree. The most frequent degree of root resorption observed in straight bracket patients was zero degree, followed by first, second degree and third degree.

• The korean journal of orthodontics
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• v.27 no.2
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• pp.327-334
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• 1997

The purpose of this study was to evaluate clinical applicability of light cured glass ionomer cement as a othodontic adhesive. The metal brackets and plastic brackets were bonded with light cured glass ionomer cement(Fuji Ortho $LS^{(R)}$) after polishing with a slurry of pumice, surface conditioning with 10% polyacrylic acid and chemically cured resin(Mono-$Lok2^{(R)}$) after acid etching with 38% phosphoric acid on the extracted human bicuspids. The shear bond strength was tested with a universal testing machine(HGS-100A, Shimadzu Co., Japan) after storage in normal saline at $37^{\circ}C$ or 24 hours and 48 hours. The results were as follows: 1. The shear bond strength of light cured glass ionomer cement group polished with a slurry of pumice was significantly lower than that of chemically cured resin group(P<0.01). 2. The shear bond strength of light cured glass ionomer cement group conditioned with 10% polyacrylic acid was significantly lower than that of chemically cured resin group(P<0.01). 3. The shear bond strength of light cued glass ionorner cement group conditioned with 10% polyacrylic acid was slightly higher than that of light cured glass ionomer cement group polished with a slurry of pumice, but there was no significant difference(P>0.05). 4. There was no significant difference between metal bracket group and plastic bracket group irrelevant off enamel conditioning(P>005). In summary, although the shear bond strength of light cured glass lionomer cement was lower than that of chemically cured resin, it night be clinically applicable.

• The korean journal of orthodontics
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• v.37 no.4
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• pp.283-292
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• 2007

The purpose of this study was to evaluate the clinical usefulness of 4 self etching primers by measuring the shear bond strength of orthodontic brackets and examining the failure pattern of bracket-tooth interfaces. Methods: Seventy-five, defect-free, premolars were randomly assigned into five groups: control group (37% phosphoric acid + Transbond XT primer) and self etching primer treated groups (Transbond Plus self etching primer, Unifil bond, Clearfil SE bond, and Adhese). The shear bond strength was measured with a universal testing machine and the amount of residual adhesive remaining on the brackets after debonding was assessed by the adhesive remnant index (ARI). Results: The results showed that the groups conditioned with self etching primer had significantly lower shear bond strength than the control group (p < 0.05), although clinically acceptable. However, there were no significant differences in shear bond strength among the self etching primer groups (p > 0.05). Evaluation of the ARI scores indicated there was less resin remnant on the teeth in the groups conditioned with self etching primers, although not statistically significant. Conclusion: The results of this study suggest that all four of the self etching primers have shown acceptable bond strength for clinical use.

• The korean journal of orthodontics
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• v.33 no.6 s.101
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• pp.475-483
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• 2003

The purpose of this study is to evaluate hard and soft tissue changes following the subapical osteotomy in bimaxillary dentoalveolar protrusion patients requiring maximal retraction adult female patients was selected. Surgical procedures were performed by the same surgeon, anterior subapical osteotomy techniques were employed on the maxilla and cephalometric radiograms were traced and superimposed using the best-fit method and two reference The results were as follows 1. The bodily movement of the maxillary anterior segment was achieved in a posterior moved posteriorly with a slight correction of the lower incisors. 2. The horizontal soft tissue measurements changed significantly after treatment, but Nt and Sn vertical soft tissue measurements indicated that Ls moved inferiorly and Li superiorly. 3. The correlation between hard and soft tissue changes indicated that ${\Delta}HId/{\Delta}HLi,\;{\Delta}HId/{\Delta}LL-Eline,\;{\Delta}Hpt.B/{\Delta}HILS,\;and\;{\Delta}UI-FH/{\Delta}NL$ were significant. 4. More lower lip relative to upper lip retraction was demonstrated in relation to Rickett's E-line. The ratio between upper lip displacement was $50\%$, and between the lower incisor and lower lip displacement was $60\%$. We conclude from the results that the anterior subapical osteotomy is an efficient treatment severe dentoalveolar protrusion and desire rapid results.

• The korean journal of orthodontics
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• v.40 no.2
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• pp.87-94
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• 2010

Objective: Many studies have carried out research on comparisons between laser etching and conventional etching systems to investigate methods of reinforcing shear bond strength. The purposes of this study were to assess the efficiency of bonding with erbium, chromium doped: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser etching combined with the conventional etching technique. Methods: Sixty-four sound premolars, extracted for orthodontic purposes, were randomly divided into 4 groups and treated in the following manner. First group, conventional etching of 37% phosphoric acid for 15 seconds (control); second group, 1.5 W laser etching for 10 seconds followed by conventional etching; third group, conventional etching followed by 1.5 W laser etching; fourth group, 1.5 W laser etching for 15 seconds only. We assessed the shear bond strength, the surface characteristics, and the adhesive remnant index scores between all groups. Results: Experimental groups showed higher shear bond strength than the control group. But no statistically significant differences were found between the second and third groups. Adhesive remnant scores were compared with the Kruskal-Wallis test, and no statistically significant differences were found between all groups. Conclusions: To obtain maximum shear bonding strength, a combined technique of Er,Cr:YSGG and 37% phosphoric acid is useful even though it may be inconvenient.