• The korean journal of orthodontics
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• v.24 no.4 s.47
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• pp.969-982
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• 1994

This study was designed to investigate the stress distribution, intensity and force mechanism derived from the MEAW by photoelastic stress analysis of the artificial teeth and surrounding bone composed of photoelastic material(PL-3) The findings of this study were as follows, 1. In case of no elastic on the MEAW with tip back, the moderate stress was observed on the molar and canine area, and the light stress was observed on the other area. 2. In case of the vertical elastic on the plain A.W, and the MEAW without tip back, the great stress was observed on the lateral incisor area, but on the MEAW with tip back, the moderate stress was observed on the anterior area and molar area. 3. In case of the C III elastic on plain A.W., the stress was concentrated on the anterior area hanged by elastic but on the MEAW without tip back, the stress was transmitted equally from the anterior area to the posterior teeth area. On the MEAW with tip back, the great stress was observed on the anterior and molar area. 4. In case of the C III elastic on the plain A.W., the stress was concentrated on the posterior area hanged by elastic but on the MEAW without tip back, the stress was transmitted equally from the posterior area to the anterior area. On the MEAW with tip back, the great stress was observed on the posterior area and the moderate stress was observed on the anterior area.

• The korean journal of orthodontics
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• v.21 no.1 s.33
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• pp.31-51
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• 1991

This study was designed to survey the stress distributions and deflections which were derived from MEAW by the computer-aided three dimensional finite element analysis of teeth and surrounding bone composed of 2839 solid elements and 4621 nodes. MEAW model was also made using the 90 beam elements and the results were expressed by quantitative and visible ways. The findings of this study were as follows. 1 In case of vertical load on the MEAW there were extrusions of anterior teeth and upright effects of the posterior teeth. 2. Without applying the vertical elastics on the MEAW there were intrusions of anterior teeth, but relatively mild force was transmitted to the posterior teeth area. Torque forces were observed on the incisors and molars, and canine was intruded without torque. 3. The magnitudes of forces were different by the amounts of tip back bends of MEAW. 4. The displacements were in inverse proportion to the cross section areas of the wires according to the experiment using the 5 different size arch wires. 5. The difference of deflections between the MEAW and plain arch wire was not so big as the theoretical one but the deflections of MEAW were much more than the plain arch wire in every X, Y, Z direction.

• The korean journal of orthodontics
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• v.34 no.5 s.106
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• pp.394-407
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• 2004

The Purpose of this study was to evaluate the effect of the lower third molar on treatment time and distal en masse movement of the lower dentition in Giass III malocclusions. Thirty subjects (9 males and 27 females) were selected, all of whom were diagnosed as Glass III malocclusion and treated by fixed appliances without premolar and/or molar extraction. They were divided into three groups Group 1 consisted of 12 subjects. whose lower third molars were not extracted during the whole orthodontic treatment. Group 2 consisted of 8 subjects. whose lower third molars were extracted after WEAW application and before removal of the orthodontic appliances. Group 3 consisted of 10 subjects whose lower third molars were extracted before MEAW application. For each subject. overall treatment time and duration of MEAW application were determined. In addition. pre-treatment and post-treatment lateral cephalometric radiographs were analyzed. All data were Processed statistically with ANOVA, and the conclusions were as follows: There was no significant difference among the groups in overall treatment time However, duration of MEAW application was longer in Group 2 than in Group 1 or Group 3. The overjet that was established after orthodontic treatment was largest in Group 3, in which the lower third molars were extracted befor MEAW application. After orthodontic treatment, IMPA decreased in Group 3. but increased in Group 1 and Group 2. There was no significant difference among the three groups in the translation of lower second molars However the tipping movement of lower second molars was significantly different, highest in Group 2 and lowest in Group 1 Therefore. it is thought to be better for the orthodontic treatment of Class III malocclusions to extract the lower third molars before MEAW application. In Group 2, the mandibular plane angle was decreased as a result of forward rotation of the mandible This skeletal change was thought to bring about the difficulty of treatment.

• The korean journal of orthodontics
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• v.29 no.6 s.77
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• pp.673-688
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• 1999

This study was conducted in order to analyze the mechanical characteristics of multiloop edgewise archwire (MEAW). The purposes were 1) to compare load deflection rate (LDR) of MEAW with that of various other arch wires in the individual interbracket span, 2) to compare the wire stiffness in the interbracket span with that in the multi-L-loop region (the span from distal border of the bracket of the lateral incisor to the mesial border of the buccal tube of the second molar), and 3) to verify the experimental results with theoretically derived formula. The single L-loops of five different horizontal lengths and multi-L-loops for the upper and lower arches were made out of .$016\times.022$ permachrome stainless steel wire. Straight segment of plain stainless steel, TMA and NiTi wire of the same dimension were prepared. The LDR was measured using Instron model 4466 with the load cell of 50N capacity at cross head speed of 1.0mm/min, and maximum deflection of 1.0mm. Five specimens were tested under each experimental condition. The wire stiffness number for each interbracket region and multi-L-loop region was calculated from the LDR and the interbracket spans. By dividing the theoretical model of multi-L-loop into 35 linear segments, the energy stored in each segment was obtained. Then the LDR and wire stiffness of single L-loop and multi-L-loop were calculated and compared. The findings were as follows : 1) The average LDR of MEAW in the individual interbracket region was 1/1.53 of that of the NiTi,1/2.47 of TMA and 1/5.16 of the plain stainless steel wire. 2) The wire stiffness of MEAW in the multi-L-loop region was 1.53 times larger than that in the interbracket region, and the LDR was almost twice as large as that of NiTi in that region. 3) According to the theoretically derived equation, the wire stiffness of the single L-loop was lower than that of multi-L-loop. The results of this study suggest that MEAW has the unique mechanical Property which could allow individual tooth movement and transmit elastic force effectively through the entire arch wire.

• Journal of the korean academy of Pediatric Dentistry
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• v.24 no.3
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• pp.637-649
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• 1997

Early orthodontic treatment in growing children requires the removable orthodontic appliances. The removable orthodontic appliance can be used in the primary dentition and mixed dentition. The purposes of use of removable orthodontic appliance in prmary dentition or mixed dentition are the interception of skeletal or dental malocclusion, guiding the normal dentition, and retention after comprehensive orthodontic treatment. Therefore, it is needed to use the removable orthodontic appliance in children with malocclusion. This report presents cases of growing children with skeletal class II and III malocclusion treated with removable orthodontic appliance during mixed dentition and Multiloop Edgewise Arch Wire(MEAW) during permanent dentition. The results obtained through these cases were summarized as follows : 1. Removable orthodontic appliances guide normal dentition and skeletal growth in growing children. 2. Removable orthodontic appliances play an important role in intercepting malocclusion in mixed dentition before use of fixed orthodontic appliance. 3. MEAW can be applied to finishing stage of all cases and is effective in correction of occlusal plane, achievement of interdigitation, and control of dental inclination. 4. It is needed that removable appliances are used during mixed dentition through correct diagnosis and fixed appliance are used in permanent dentition.

• The korean journal of orthodontics
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• v.20 no.2
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• pp.267-280
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• 1990

The purpose of this study was to investigate the force mechanism of Multiloop Edgewise Arch Wire and the intensity and distribution of stresses with vertical and intermaxillary elastics. The obtained results were as follows. 1. When plain wires were inserted and vertical and intermaxillary elastics were used in the upper and lower arch, the stresses of the anterior and posterior ends of wires were observed greatly but the stresses of the premolar were very small. 2. When MEAW were inserted in upper and lower arch, the upper 1st and 2nd premolar and the lower 1st premolar were extruded greatly. 3. In the area of the upper 1st molar and the lower 2nd premolar and the lower 1st molar, any stresses were not observed. 4. The vertical elastic counteracted the intrusion force of the MEAW in the anterior teeth but could not affect on posterior teeth. Using with the Class II elastics, the distal tipping force and extrusion force were exerted in the upper anterior teeth and the intrusion forces of the lower anterior teeth were relieved. Using with the Class III elastics, the extrusion force were exerted in the upper and lower anterior teeth, the distal tipping force were increased in the lower posterior teeth. 5. The Class II elastic counteracted the anterior intrusion force of the MEAW and extruded and tipped mesially the lower 2nd molar. The intrusion force of the MEAW also could not overcome the extrusion force of the class II elastics. 6. When the Class III elastics were engaged, the upper 2nd molar was extruded in spite of the intrusion forces of the MEAW and the extrusion forces of the lower anterior teeth and distal tipping forces in the posterior teeth were observed.

• The korean journal of orthodontics
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• v.30 no.2 s.79
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• pp.127-142
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• 2000

This study have been carried out to find out the mechnical effect of Multiloop Edgewise Arch Wire(MEAW) making use of the finite element method. The tip back bend of MEAW taken in this analysis is $5^{\circ},\;10{\circ}\;and\;15{\circ}$. In addition, Class II or up & down elastic is applied to find out stress distribution and their values in PDL. A adult male of normal occlusion was selected to create the models of teeth and PDL. And the model of MEAW was also created using commercial finite element code (ANSYS version 5.2). The MEAW is forcibly engaged with a class II or up & down elastic, to determine the initial stress generated in PDL. Comparing the compressive and tensile stress at each reference-planes, following results are obtained. 1. When a MEAW of $5^{\circ},\;10{\circ}\;15{\circ}$ tip back bend was engaged with Class II or up & down elastic, the distribution of compressive, tensile stress in entire PDL is similar in each case. 2. The values of compressive and tensile stress in PDL is higher in $15{\circ}$ tip back bend case than in $10{\circ}\;or\;15{\circ}$ tip back bend case. 3. In the distal PDL of 1st and 2nd molar, compressive stress appears. The compressive area is more wide and its values is higher in PDL of 2nd molar than those in 1st molar. The compressive area and its values become more wide and higher according to the increase of the tip back bend. 4. The values of compressive stress are comparatively smaIIer in PDL of molars than those in premolars. 5. Comparing class II and up & down elastic case, tensile stress values in anterior teeth PDL are smaller md their distribution is more wide in up & down elastic case than class If elastic case. On another hand, there is no difference in distribution and stress values in PDL of posterior teeth between two cases. 6. Comparing the tensile area in PDL of anterior teeth, tensile stress values are maximum in PDL of canine.

• The korean journal of orthodontics
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• v.16 no.1
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• pp.35-49
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• 1986

Etiologies and traditional treatment modalities regarding anterior open-bite were discussed to elucidate the advantages and disadvantages. And an emphasis was placed on the understanding of the true nature of anterior open-bite. Most anterior open-bite malocclusions can be treated with a high degree of sucess and stability without surgical intervention with the congnizance of the anatomy, the physiology and the dynamics of orthodontic mechanotherapy. In this regard, a Multiloop Edgewise Arch Wire (MEAW) Technic, which has been developed during the past twenty years by Dr. Kim, was introduced. Three cases with anterior open-bite malocclusion were presented to demonstrate the mechanotherapy.

• 대한치과교정학회:학술대회논문집
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• 1997.11a
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• pp.56-56
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• 1997

• The korean journal of orthodontics
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• v.24 no.3 s.46
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• pp.735-758
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• 1994

This study was designed to investigate the displacements and reaction forces of teeth caused by the application of the rectangular shape-memory arch wires with curve of Spee. Computer-aided three dimensional finite element method was adopted. This finite element model consists of brick element for teeth, beam element for the wire, and contact element for the periodontal ligament. And the application of the MEAW(Multiloop Edgewise Arch Wire) was also studied so that the results of the two methods can be compared each other. Total number of the nodes and elements were found to be 5925 and 4031, repectively. In addition, several types of elastics and corresponding displacements and reaction forces were examined. The findings of this study were as follows: 1. When the rectangular shape-memory arch wire with curve of Sun was used alone, the intrusion and labioversion was noticeable on the upper incisors, while the upper molars showed less intrusion. With MEAW, the intrusion and labioversion of the upper incisors were slightly larger than those when the shape-memory arch wire was used, but on the upper molars the opposite result was obtained with respect to the intrusion. 2. The shape-memory arch wire with the vertical elastics caused the larger downward displacement on the upper canine than that when the MEAW was used with the vertical elastics. However, the downward displacement of the upper incisors was larger in MEAW. The uprighting and buccoversion of the molars were observed in both cases. 3. The use of the Class II or III elastics showed the extrusion and changes in torque of the corresponding teeth. The downward displacement of the upper canine was increased when the Class II and vertical elastics were applied simultaneously, but it was decreased when both of the Class III and vertical elastics were used.