• The korean journal of orthodontics
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• v.38 no.6
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• pp.376-387
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• 2008

Objective: The purpose of this study was to compare the three dimensional changes of tooth movement using four different types of maxillary molar distalization appliances; pendulum appliance (PD), mini-implant supported pendulum appliance (MPD), stainless steel open coil spring (SP) and mini-implant supported stainless steel open coil spring (MSP). Methods: These experiments were performed using the Calorific $machine^{(R)}$ which can simulate dynamic tooth movement. Computed tomography (CT) images of the experimental model were taken before and after tooth movement in 1 mm thicknesses and reconstructed into a three dimensional model using V-works $4.0^{TM}$. These reconstructed images were superimposed using Rapidform $2004^{TM}$ and the direction and amount of tooth movement were measured. Results: The mean reciprocal anchor loss ratio at the first premolar was 17 - 19% for the PD and SP groups. The appliances using mini-implants (MPD or MSP) resulted in less anchorage loss (7 - 8%). On application of a pendulum appliance or MPD, distalization was obtained by tipping rather than by bodily movement. Furthermore, the maxillary second molar tipped distally and bucally. But on application of MSP, distalization was achieved almost by bodily movement. Conclusions: Regarding tooth movement patterns during molar distalization, stainless steel open coil spring with indirect skeletal anchorage was relatively superior to other methods.

• The korean journal of orthodontics
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• v.39 no.6
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• pp.402-419
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• 2009

Successful treatment of the non-growing patient with an open bite of either dental skeletal pattern often presents a difficult challenge. The morphologic pattern in anterior open bite is characterized by longer vertical dimensions, an increase in development of the maxillary posterior dento-alveolar structure and a steep mandibular plane. In such cases, molar intrusion would be a good remedy for treatment. This article reports the successful treatment and retention of two anterior open-bite cases. We used orthodontic mini-implants for treatment and a circumferential retainer with posterior bite block or skeletal fixed retainer for retention. The diagnostic criteria and mechanics for appropriate treatment are discussed. Our results suggest that open bite can be reduced successfully with intrusion of molars using orthodontic mini-implants (OMI) without orthognathic surgery, and that circumferential retainer with posterior bite block and skeletal fixed retainer are effective for retention.

• The korean journal of orthodontics
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• v.38 no.3
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• pp.149-158
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• 2008

Objective: The purpose of this study was to investigate the stability of mini-implants in relation to loading time. Methods: A total of 48 mini-implants (ORLUS, Ortholution, Korea) were placed into the buccal alveolar bone of the mandible in 8 male beagle dogs. Orthodontic force (200-250gm) was applied immediately for the immediate loading group while force application was delayed for 3 weeks in the delayed loading group. For the subsequent loading periods (3, 6, 12 weeks), BIC (bone implant contact) and BV/TV (bone volume/total volume) and mobility test were carried out. Results: The immediate loading group showed no changes in BIC from 3 to 12 weeks, while the delayed loading group showed a significant increase in BIC between 3 and 12 weeks (p<0.05). The BV/TO of the delayed loading group significantly increased from 6 to 12 weeks of loading (p<0.05), while the BV/TV of the immediate loading group decreased from 3 to 12 weeks of loading. However, there was no significant difference in BV/TV between experimental groups. The mobility of the immediate loading group was not significantly different from that of the delayed loading group after 12 weeks of loading (p<0.05). Conclusions: These results showed that immediate loading does not have a negative effect on the stability of mini-implants compared to the early loading method in both the clinical and histomorphometric point of view.

• Journal of Dental Rehabilitation and Applied Science
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• v.27 no.3
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• pp.293-304
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• 2011

The purpose of this study was to investigate the displacement and pattern of stress distribution on periodontal ligaments of maxillary first and second molar, and on orthodontic mini-implant (OMI) surface, according to three different insertion angles to the bone surface of OMI using Dragon helix appliance, which is a newly introduced scissors-bite correcting appliance. OMI were placed between second premolar and first molar with three different insertion angles (45, 60, 90 degrees). Displacement and maximum stress distribution area (MSDA) were analyzed by finite element analysis. When the insertion angle to the alveolar bone surface was 90 degrees, maxillary first and second molar both exhibited MSDA at the palatal root apex. Maxillary first molar did not show any significant displacement, while the second molar exhibited intrusive and palatal displacement. On the OMI, as the insertion angle decreased, the MSDA shifted towards the tip, and the amount of displacement had increased. When the OMI was inserted at a 90 degree angle, anchor loss was minimized and scissors-bite correcting effect was maximized.

• The Journal of the Korean dental association
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• v.57 no.11
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• pp.654-663
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• 2019

This case report describes the management of a 30-year-old woman with hopeless mandibular first molars and right maxillary second premolar. The treatment plan included mandibular second and third molar protraction after extraction of mandibular first molars. Mini-implants were placed between roots of first and second premolar. Sliding mechanics with lever arm was used to prevent inclination of molars. A good functional occlusion was achieved in 38 months without clinically significant side effects. Most of the extraction space of mandibular first molar was closed by protraction of second and third molars. The skeletal Class II pattern was improved by counterclockwise rotation of mandible through reduction of wedge effect. Mandibular molar protraction with orthodontic mini-implants in adequate cases would be a great alternative to prosthetic implant and reduce the financial and surgical burden of patients.

• The korean journal of orthodontics
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• v.37 no.3 s.122
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• pp.212-219
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• 2007

Objective: The purpose of this study was to provide an anatomical reference for cortical bone and soft tissue thickness, and the attached gingiva width in the mandible. Methods: Fifteen males and fifteen females participated in this study. An acrylic template was fabricated and the radiopaque markers were bonded on the estimated alveolar crest to take measurements of the hard and soft tissue thickness at the same locations. CT images were taken in samples wearing an acrylic template. Cortical bone and soft tissue thickness were measured at 2, 4, 6 and 8 mm from the alveolar crest in interradicular spaces from central incisor to first permanent molar. The attached gingival width was calibrated. Results: Cortical bone thickness was $1.33{\pm}0.38mm$ and soft tissue thickness was $1.49{\pm}0.54mm$. Cortical bone thickness was increased in the posterior area, while it was not the case for the soft tissue thickness. In addition, the total thickness was $2.82{\pm}0.70$. The attached gingival width was wider in the anterior area compared to that in posterior area. Conclusion: These results suggest that the attached gingiva width should be considered upon placement of mini-implants in the mandibular posterior area for orthodontic anchorage.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.4
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• pp.404-411
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• 2012

Tooth impaction is defined as a failure of tooth eruption resulting from the physical obstacles in the eruption path or the abnormal position of the tooth germ. Impaction of mandibular second molar is relatively rare, and it may incite pathologic conditions such as dental caries, periodontitis, or root resorption of adjacent first molar. Thus, early diagnosis and treatment is recommended. In the first case, a 10-year-old male patient, was treated by brass wire to separate the bilaterally impacted mandibular second molars. In the second case, a 12-year-old female patient, was treated with Humphrey appliance for impacted mandibular left second molar, which was detected during a periodical dental examination. In the third case, a 17-year-old female patient with impacted mandibular right second molar, was treated by uprighting spring with mini-implant anchorage around premolar area. In the last case, an 18-year-old male patient, was treated with mini-implant placed on the ramus of mandible connected to the orthodontic buttons bonded on impacted mandibular left second molar by elastic thread.

• 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.41 no.5
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• pp.354-360
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• 2011

Objective: To investigate the effects of different pilot-drilling methods on the biomechanical stability of self-tapping mini-implant systems at the time of placement in and removal from artificial bone blocks. Methods: Two types of artificial bone blocks (2-mm and 4-mm, 102-pounds per cubic foot [102-PCF] polyurethane foam layered over 100-mm, 40-PCF polyurethane foam) were custom-fabricated. Eight mini-implants were placed using the conventional motor-driven pilot-drilling method and another 8 mini-implants were placed using a novel manual pilot-drilling method (using a manual drill) within each of the 2-mm and 4-mm layered blocks. The maximum torque values at insertion and removal of the mini-implants were measured, and the total energy was calculated. The data were statistically analyzed using linear regression analysis. Results: The maximum insertion torque was similar regardless of block thickness or pilot-drilling method. Regardless of the pilot-drilling method, the maximum removal torque for the 4-mm block was statistically higher than that for the 2-mm block. For a given block, the total energy at both insertion and removal of the mini-implant for the manual pilot-drilling method were statistically higher than those for the motor-driven pilot-drilling method. Further, the total energies at removal for the 2-mm block was higher than that for the 4-mm block, but the energies at insertion were not influenced by the type of bone blocks. Conclusions: During the insertion and removal of mini-implants in artificial bone blocks, the effect of the manual pilot-drilling method on energy usage was similar to that of the conventional, motor-driven pilot-drilling method.