• The korean journal of orthodontics
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• v.21 no.3
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• pp.635-656
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• 1991

It was the aim of this investigation to evaluate some histologic aspect of rat pulp tissue after it had been compromised by an experimental orthodontic force. Experimental animals of thirty five Spraque-Dawley rats were employed. The first upper molars had been successively mesial moved (initial load 100 gr.) with a closed coil spring during 21 days. The experimental periods were set on immediate, 1 day, 1 week, 2 weeks, 3 weeks, 4 weeks following retention time. On each experimental period, the rats were killed and prepared for the light microscopy. After prepared with H/E stain and Gomori's one-step trichrome stain, the specimens were analyzed with evaluation criteria which were adopted in this study. The result may be summarized as follows; 1. The main pulp changes due to experimental orthodontic force included vacuolization of odontoblastic layer, circulation disturbance, root resorption, reduced pulp collagenous fiber density and mean cell count of pulp fibroblast in the immediate group. 2. The pulp tissue changes were revealed reversible because the relieved pulp tissues from experimental orthodontic force were recovered rapidly in each evaluation criteria during retention periods. 3. Compared with normal control group, pulp collagenous fiber density were decreased in immediated group (p < 0.01), but increased in each retention groups. These seem to suggest that the pulp tissues were aged after experimental orthodontic force conditions. 4. Compared with normal control group, mean cell counts of pulp fibroblasts were decreased in immediate group (p < 0.05), but increased continuous in each retention groups. These seem to indicate that the pulp tissues were highly regenerative after experimental orthodontic force conditions. 5. Compared with normal control group, root resorptions occurred in all immediate specimens (p < 0.01) and they were healed in each retention periods, but often observed in 4 weeks retention group. These seem to indicate that root resorptions were recovered slowly after experimental orthodontic force conditions.

• The korean journal of orthodontics
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• v.33 no.2 s.97
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• pp.91-102
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• 2003

This study was performed to investigate the effect of immediate orthodontic force on soft md hard tissues surrounding C-Palatal $Plate^{TM}$ in beagle Dog. Immediately after this appliance was implanted on the midpalate of 4 adult beagle Dogs, 400gm continuous orthodontic force was applied. Experimental animals were euthanized at 8weeks, 18weeks, and 22weeks (including post-removal healing time of 4weeks), and a control animal was euthanized at 8weeks after implantation without orthodontic force application. The appliance and the surrounding tissue were studied radiographically, macroscopically, and histologically. The results were as follows: 1. The lateral radiographs taken after euthanasia showed very slight displacement of the vortical plate in the experimental animals, compared with the control animal. Mobility test of all animals confirmed primary stability without any increase of mobility during experimental period. 2. No pathologic changes were found in the healing condition of covering soft tissue and bone-screw interface in experimental animals as well as a control animal. 3. Osseointegration was achieved in the bone-screw interface in 8weeks after implantation and the amount of osseointegration increased in 18weeks. There was little difference of osseointegration between the compression side and the tension side. 4. In the marginal bone area, slight bone apposition and resorption were found regardless of compression and tension side, while there was no change in the control animal. 5. Both 8week-animal and 18week-animal showed the new bone apposition along the surface of screws which were perforated into the nasal cavity, while the control animal showed no change. 6. After 4weeks of plate removal, the covering epithelium was repaired intactly, while the connective tissue showed loose and irregular rearrangement and the connective tissue capsule remained. The C-Palatal $Plate^{TM}$ manifested sufficient anchorage capacity in the context of histological study as well as clinical outcomes, when immediate orthodontic force was applied after implantation.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.3
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• pp.431-437
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• 2000

Traumatic intrusive luxation, an occurrence common in the primary dentition but one that occurs rarely in the permanent dentition, has a poor prognosis. There have been many treatment approaches such as allowing the tooth to reerupt spontaneously, surgical repositioning and immediate luxation, surgical luxation, and orthodontic repositioning; but all have their own drawbacks. Meanwhile, Turley et al. (1987) have proposed surgical and orthodontic combination therapy to treat intrusion. Surgical and orthodontic combination therapy means to apply the orthodontic traction force immediately after surgical luxation. If ankylosis occurs, orthodontic force may be applied after re-luxation repeatedly. But in cases of complete intrusive luxation, it would be not feasible to bond an orthodontic button or bracket on the tooth directly. Thus, in this case, traction of the tooth was attempted after surgically repositioning it close to the probable original socket site to promote better healing.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.41 no.5
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• pp.240-245
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• 2015

Objectives: This study was performed to evaluate patterns of failure time after insertion, failure rate according to loading time after insertion, and the patterns of failure after loading. Materials and Methods: A total of 331 mini-implants were classified into the non-failure group (NFG) and failure group (FG), which was divided into failed group before loading (FGB) and failed group after loading (FGA). Orthodontic force was applied to both the NFG and FGA. Failed mini-implants after insertion, ratio of FGA to NFG according to loading time after insertion, and failed mini-implants according to failed time after loading were analyzed. Results: Percentages of failed mini-implants after insertion were 15.79%, 36.84%, 12.28%, and 10.53% at 4, 8, 12, and 16 weeks, respectively. Mini-implant failure demonstrated a peak from 4 to 5 weeks after insertion. The failure rates according to loading time after insertion were 13.56%, 8.97%, 11.32%, and 5.00% at 4, 8, 12, and 16 weeks, respectively. Percentages of failed mini-implants after loading were 13.79%, 24.14%, 20.69%, and 6.9% at 4, 8, 12, and 16 weeks, respectively. Conclusion: Mini-implant stability is typically acquired 12 to 16 weeks after insertion, and immediate loading can cause failure of the mini-implant. Failure after loading was observed during the first 12 weeks.

• The korean journal of orthodontics
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• v.25 no.1 s.48
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• pp.101-110
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• 1995

The purpose of this study was to observe the tissue response to the orthodontic force applied immediately after buccal horizontal subapical osteotomy of maxilla. Five mongrel cats weighing about 2.5 Kg were used for this experiment. The left upper canine and premolar of each cat served as a experimental side and the right ones as a control side. On the experimental side, a 100gm orthodontic force was applied between the upper canine and premolar immediately after the osteotomy. On the control side, the same orthodontic force was applied without the osteotomy. After 7days, the experimental animals were sacrificed. The results were as follows: 1. In the pressure zones of the experimental group, significant increase of osteoclasts and direct resolution along the alveolar bone surface was observed as compared with those of the control group. 2. In the pressure 2ones of the experimental group, a less extensive hyalinized zone was observed than those of the control group. 3. In the pressure zones of both group, no root resorption was found. 4. Tn the tension zones of the experimental group, new bone deposition increased along the alveolar bone surface as compared with those of the control group. In conclusion, the results suggest the possibility that early orthodontic treatment after orthognathic surgery may have some benefits if the stability of the repositioned segment at surgery is secured.

• 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.

• The korean journal of orthodontics
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• v.29 no.6 s.77
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• pp.699-706
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• 1999

Anchorage plays an important role in orthodontic treatment. Endosseous implants may be considered adequate firm anchorage. However, clinicians have hesitated to use endosseous implants as orthodontic anchorage because of limited implantation space, high cost, and long waiting period before osseointegration occurs. Recently, some clinicians have tried to use titanium miniscrews and microscrews in treatment due to their many advantages such as ease of insertion and removal, low cost, immediate loading, and the ability to place microscrews in any area of alveolar bone. The author treated a case with skeletal cortical anchorage using titanium microscrew implants. During six months of orthodontic force application from skeletal cortical anchorage, the author could get 4 mm bodily retraction and intrusion of upper anterior teeth. The most outstanding result was a 1.5 mm posterior refraction of the upper posterior teeth. The titanium microscrew implants had remained firm and stable throughout treatment. These results indicate that skeletal cortical anchorage might be a very good option.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.2
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• pp.256-261
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• 2000

Trauma to the tooth is the most common accidents in pediatric dentistry and tooth fracture occurs frequently. Fracture is classified into crown fracture, root fracture, and crown-root fracture which involves both. Also, it is classified into simple or complicated fracture depending on whether the pulp is exposed or not. When the fracture is extended down to the subgingival level following the long axis of the root, or when more than 1/3 of the root is involved, extraction is the primary treatment. But alternative treatment such as extruding the root fragment with orthodontic force and restoring it, or intentionally extracting the tooth and replanting it to a position which it can be restored. This is a case report on intentional replantation of a traumatized maxillary central incisor with crown-root fracture of a patient with mixed dentition. The teeth was extracted and immediate endodontic treatment, retrograde filling and resin restoration were carried out.

• The korean journal of orthodontics
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• v.24 no.2
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• pp.303-317
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• 1994

This study was designed to measure the changes in the titer of tooth root antibodies accompanying root resorption associated with orthodontic tooth movement in dogs to explore a role of the specific immune response in root resorption during orthodontic tooth movement. Five adult mongrel dogs, 2 years of age, were used in the study. Six lower incisors were extracted as sources of homologous antigen in the dogs. Tooth root antigen preparations were made from a 6M Guanidine-HCl-10% EDTA(pH5.0) extract of these root dentins. Root resorption was elicited by intrusion of six maxillary incisors with 200-250gm intrusive force. In 9th week, resorbing six maxillary anterior teeth were extracted. Serum samples were taken from each dog prior to intrusion and weekly for 11 consecutive weeks. Serum autoantibody titers were determined with an enzyme-linked immunosorbent assay. As controls for antibody specificity, sera which were previously incubated with tooth root antigen as well as sera to an unrelated bacterial antigen (Porphyromonas gingivalis 33277) for 3 hours at 25 were measured in all runs. Root resorption was monitored monthly using occlusal radiographs. And then root resorption patterns were observed with a zoom stereo microscope (Model SZH-121, Olympus optical Co. Ltd.). Incisors did not show clear radiographic evidence of significant and progressive root resorption, but periodontal ligament space had widened. But root resorption was observed on the apical regions of the maxillary incisors with a zoom stereo microscope. Teeth showed the shallow depression generally accompanying deep resorption. These demonstrate a slight tendency for an immediate decrease followed by rebound to levels above the pre-treatment baseline. A peak titer of autoantibody to dentin antigen occurred on day 28, then steadily decreased during the 9th week period as the roots resorbed and then rapidly spiked in animals when the resorbing teeth were extracted. When sera is incubated with tooth root antigen, serum activity in the ELISA was almost absent. This is because serum activity in the ELISA could be removed by absorption of the serum with dog dentin antigen. Serum ELISA activity to the unrelated bacterial antigen remained essentially unchanged in all animals throughout the experimental period. When the time course of changes in autoantibody to homologous tooth root antigen prepatration and unrelated bacterial antigen was compared, no significant differences were found(${\alpha}=0.05$). In general, the overall pattern of changes in autoantibody was similar to the two antigens. These findings suggest the possibility that these immunologic changes precede a significant development of root resorption lesions rather than merely reflecting their presence. Therefore, this suggests that the changes of antibody levels may have some predictive value for root resorption.