• Journal of the Korean Academy of Esthetic Dentistry
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• v.29 no.2
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• pp.84-91
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• 2020

Regeneration of interdental papilla damaged by periodontal disease is a very challenging task. So far, many dentists have devised and introduced great surgical methods. Comparing the pros and cons of the methods introduced so far, I came up with the best way to regenerate interdental papilla. Temporarily creating space between narrow interdental papilla, which cannot be solved by periodontal surgery alone, was a great help for connective tissue graft(CTG). The CTG was performed using a microblade, and only one vertical incision was performed off the gingival margin, and the graft was performed by inserting the grafts through here. Along with the orthodontic treatment, the area between the narrow interdental papilla was widened to make it easier for the CTG was carried out. After a period of maintenance, I was able to gather the teeth again with orthodontic force and regenerate the interdental papilla. I named this method ELSA (Enlargement of space-Labial graft-Squeezing-for Augmentation of papilla) technique.

• The korean journal of orthodontics
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• v.31 no.3 s.86
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• pp.369-379
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• 2001

The aim of this study was to investigate the periodontal response according to the timing of orthodontic force application after bone graft into the angular bony defect. Nine dogs were divided into three groups, 2, 4, and 6 weeks, according to the timing of orthodontic force application after bone graft. Periodontal angular bony defects were created surgically at the distal aspect of both maxillary third incisors. Two weeks later, flap operation was performed to eliminate inflammation and reference notch was made on the root surface at the level of the bottom of each defect. Demineralized freeze-dried bone was implanted on the left side whereas only debridement was done on the other side. Experimental tooth movement was executed during 8 weeks on both graft and non-graft sides. After 2 weeks of retention period, animals were sacrificed for histologic specimens. The results were obtained as follows 1 New bone formation was more pronounced in the graft side than in the non-grad side in all experimental animals. 2. In the 6-week group, new bone and cementum formation was observed in more than half from the notch to the cemento-enamel junction, and the zone of connective tissue attachment was found without apical migration of junctional epithelium. 3. In the 4-week group, the amount of new bone formation was smaller than in the 6-week group whereas the overall remodeling pattern was similar. 4. New bone formation was confined to around the notch and the junctional epithelium migrated apically to the level of the notch with no connective tissue attachment and cementum formation in the 2-week group. The results of the present study suggest that periodontal response may be influenced by the timing of orthodontic force application after bone graft into angular bony defect.

• The korean journal of orthodontics
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• v.28 no.3 s.68
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• pp.441-452
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• 1998

The c-fos is known as neuronal marker of second neurons which is activated by noxious peripheral stimulation. To investigate the changes of c-fos el(pression in the trigeminal nucleus complex during tooth movement, immunohistochemical study was performed. Experimental rats(9 weeks old, 210 gm 21 rats) were divided into seven groups(normal, 1 hour group, 3 hour group, 6 hour group, 12 hour group, 1 day group,3 day group). Rats in the normal group were anesthesized without orthodontic force. Rats in the experimental groups were applied orthodontic force (approximately 30 gm) to upper right maxillary molar. Frozen sections of brain stem were immunostained using rabbit antisera. The changes of c-fos expression were observed with respect to rostrocaudal distribution, laminar organization, md duration of orthodontic force application. The study results were as follows $\cdot$The c-fos nuclei in the dorsal part were observed from ipsilateral transition zone of subnucleus interpolaris and subnucleus caudalis to $C_1$ cervical dorsal horn rostrocaudally. The maximal peak point was the rostral part of subnucleus caudalis. The greatest proportion of c-fos cells were located within lamina I and II. $\cdot$The c-fos nuclei in the dorsal Part were observed from the most caudal part of subnucleus interpolaris to the middle part of the subnucleus caudalis. $\cdot$The number of c-fos immunoreactive dot increased at 1 hour group, reached its maximum at the 3 and 6 hour groups, and showed a decreasing trend after 12 hours. These results imply that nociceptive stimulation caused by continuous orthodontic force might be modulated by transition zone of subnucleus interpolaris and subnucleus caudalis, subnucleus caudalis, $C_1$ spinal dorsal hem.

• The korean journal of orthodontics
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• v.42 no.3
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• pp.118-128
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• 2012

Objective: The aim of this study was to investigate and compare the in vivo effects of prostaglandin E2 (PGE2) administered by different methods on orthodontic tooth movement and bone metabolism macroscopically, histopatologically, and biochemically. Methods: Forty-five young adult New Zealand rabbits were randomly divided into 3 experimental groups (n = 10/group), 1 positive control group (n = 10), and 1 negative control group (n = 5). The experimental rabbits were fitted with springs exerting 20-g reciprocal force on the maxillary incisors and PGE2 (10 ${\mu}g/mL$) was administered by the intravenous, submucosal, or intra ligamentous route aft er appliance insertion and on days 1, 3, 7, and 14 thereafter. All rabbits were sacrificed on day 21 and their premaxillae were resected for histologic evaluation. Results: Tooth movement was observed in the experimental and positive control groups, but the intraligamentous PGE2 group had the highest values of all analyzed parameters, including serum calcium and phosphorus levels and osteoclastic and osteoblastic populations (p < 0.001). Conclusions: Sub mucosal and intraligamentous PGE2 administration significantly increases orthodontic tooth movement and bone metabolism, but the intraligamentous route seems to be more effective.

• Journal of the korean academy of Pediatric Dentistry
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• v.24 no.4
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• pp.758-762
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• 1997

There are various types of localized tooth malpositions in the mixed dentition, such as abnormal tooth axis, anterior crossbite of some incisors, impaction, midline diastema, ectopic eruption, and so forth. We, Pediatric Dentists, have usually used removable appliances for these instances. But, removable orthodontic appliances, as is known, have marked limitations in some situations, for example, severe rotation, intrusion and extrusion, root torque, closure of large diastema, traction of impacted tooth, etc. In such cases, Whip spring, combined with fixed or removable appliance, can increase utilities of removable orthodontic appliances. The authors have applied whip springs to some cases showing localized positional and arrangement problems, and have witnessed the results as follows; 1. The refined and elaborate control of direction and magnitude of force by the operator, and accurate compliance of the patients were requisite for the treatment with it. 2. It showed special effectiveness for de rotation of incisors. Although it yields some benefit for root movement, the special consideration for incomplete roots in this age bracket was required. 3. In the localized malalignment cases in mixed dentition, uncurable with traditional removable appliances but practically unrealistic with fixed appliance therapy, the whip spring was thought to be a good alternative.

• The korean journal of orthodontics
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• v.51 no.4
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• pp.293-300
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• 2021

In this report, we demonstrate the effectiveness of the Invisalign^® system in the treatment of severe gingival recession and bone dehiscence through torque, translation, and intrusion movements in a young woman. Cone-beam computed tomography was used to assess bone parameters and check the teeth during treatment. The root of the mandibular right central incisor, which was buccally positioned and exhibited bone dehiscence of 9.4 mm, was moved toward the center of the alveolar process by using the Invisalign^® system and SmartForce^® features. The patient was monitored by a periodontist throughout the orthodontic treatment period. Her gingival recession reduced, while the bone dehiscence reduced from 9.40 mm to 3.14 mm. Thus, movement of the root into the alveolus promoted bone neoformation and treated the gingival recession. The findings from this case suggest that orthodontic treatment using the Invisalign^® system, along with periodontal monitoring, can aid in the treatment of gingival recession and alveolar defects.

• The korean journal of orthodontics
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• v.54 no.5
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• pp.265-273
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• 2024

Objective: This study aimed to investigate the effects of archwire form and power arm positions on maxillary incisors during lingual en masse retraction supported by miniscrew implants, using the finite element analysis method. Methods: Sliding mechanics for lingual en masse retraction were simulated using the finite element method. Power arms were placed mesial and distal to the maxillary canine with straight and mushroom-shaped archwires. Miniscrews provided absolute anchorage for retraction force. Results: When power arms were positioned mesial to the canine teeth, an increase in the intercanine distance was observed, while a decrease was noted when the power arms were distal to the canine tooth. Lateral incisors exhibited a greater torque loss, particularly when the power arm was mesial to the canine tooth. In the central incisors, the mushroom archwire resulted in intrusion, while the straight archwire showed an extrusion tendency. Movements in groups using the straight archwire were less controlled compared to those in groups using the mushroom archwire. Conclusions: The archwire form and the position of the power arm affected the torque loss and vertical position of incisors during lingual en masse retraction supported by miniscrew implants. The most controlled movement was achieved with the combination of a power arm positioned distal to the canine tooth and a mushroom archform.

• The korean journal of orthodontics
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• v.19 no.2
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• pp.57-73
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• 1989

The purpose of this study was to investigate the tissue response of the rat molar periodontium incident to intermittent orthodontic force. The author intended to observe the healing process of injured periodontium and the response of injured tissue to the resumed force. Oxytetracyclin 50mg/Kg was given to each rat intraperitonially. 5 days later, maxillary 1st molars were moved mesially from the incisors with closed coil spring of 100gram. 7 days later, the appliances were removed and 20mg/Kg of calcein were given intraperitonially to each rat. At the same time, maxillary left 1st molars of 15 rats were moved by the same method, but force was lowered to 20 gram. After 1 day, maxillary left 1st molars of another 15 rats were moved by the same method and 50mg/Kg of oxytetracycline was given intraperitonially. After 4 days, another 15 rats were treated as above. After 7 days, another 15 rats were treated as above. 1,4,7,10 and 14 days after change of force, 3 rats were sacrificed in each group respectively. 2 rats were decalcified, embedded in paraffin, and stained with hematoxylin-eosin stain and with Masson's trichrome stain. Another rat was embedded in polyester resin and undecalcified specimen were made. Microradiograms were taken with the undecalcified sections. Observations were made with light and fluorescence microscope. Following conclusions were made. 1. Connective tissue cells and vessels were infiltrated into the hyalinized tissue from the bony cleft and along the border of the hyalinized tissue with bone and root surface. At the same time, elimination of hyalinized tissue, bone and root resorption occurred. 2. Bone and root were resorbed directly and indirectly. 3. Hyalinized tissue was removed within 5 days after force removal. 4. Hyalinized zone was less extensive and easily removed as the rest period prolonged. 5. Hyalinized tissue developed more rapidly and extensively and lasted over 10 days as the force resumed on the already formed hyalinized tissue.

• Journal of Korean Dental Science
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• v.16 no.1
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• pp.23-34
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• 2023

Purpose: This study aims to investigate the force delivery profile of thermoformed aligners (TFA) compared with direct-printed aligners (DPA) and to explore the effect of different activation amounts on forces and moments of respective groups. A secondary objective is to observe the amount of stress relaxation that occurs over the 7~14 days when aligners are maintained in a simulated intraoral environment. Materials and Methods: An in vitro setup was created to quantify forces and moments. It consisted of a three dimensional-printed base plate and segmented maxillary teeth, placed in a semi-enclosed chamber to maintain a temperature of 37℃. Ninety clear aligners were divided into nine groups of ten aligners each based on material types (Zendura, ATMOS, TC-85) and activation amounts. Aligners were created with 0.00, 0.25- and 0.50-mm activations for lingual bodily movement of the upper left central incisor and kept on models in the "stressed" position in a 37℃ water bath. Three force components acting on the upper left lateral incisor, upper left central incisor, and upper right central incisor were measured for each time point, beginning from the initial baseline measurement, 8 hours, 16 hours, 24 hours, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, and lastly, 14 days. Result: TC-85 aligners in every activation group showed less force on teeth than Zendura and ATMOS. Significant force levels from 0.0 mm activation were present and stayed consistent over the course of 14 days. Comparisons made for baseline measurements to 7-days and 14-days showed statistically significant change from the baseline force level. Conclusion: TC-85 aligners demonstrated lower, more consistent forces with fewer side effects. Aligners can generate forces even when no activation is programmed. No major decreases in force levels over time were observed; the intra-oral clinical simulated environment and length of observation time could contribute to this.

• The korean journal of orthodontics
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• v.43 no.5
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• pp.235-241
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• 2013

Objective: The purpose of this study was to investigate whether extension of the custom base is necessary for enhancement of bond strength, by comparing the debonding forces and residual adhesives of 3 different lingual bracket systems. Methods: A total of 42 extracted upper premolars were randomly divided into 3 groups of 14 each for bonding with brackets having (1) a conventional limited resin custom base; (2) an extended gold alloy custom base: Incognito${TM}$; and (3) an extended resin custom base: KommonBase${TM}$. The bonding area was measured by scanning the bracket bases with a 3-dimensional digital scanner. The debonding force was measured with an Instron universal testing machine, which applied an occlusogingival shear force. Results: The mean debonding forces were 60.83 N (standard deviation [SD] 10.12), 69.29 N (SD 9.59), and 104.35 N (SD17.84) for the limited resin custom base, extended gold alloy custom base, and extended resin custom base, respectively. The debonding force observed with the extended resin custom base was significantly different from that observed with the other bases. In addition, the adhesive remnant index was significantly higher with the extended gold alloy custom base. Conclusions: All 3 custom-base lingual brackets can withstand occlusal and orthodontic forces. We conclude that effective bonding of lingual brackets can be obtained without extension of the custom base.