• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.1
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• pp.62-67
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• 2011

Early eruption refers to an accelerated eruption of a tooth beyond the normal eruption period. The clinical findings of an early erupted tooth with little formation of crown and/or root include severe mobility, pain on chewing, hypocalcification of the enamel, and inclination, displacement, and rotation of the tooth. The radiographic findings include underdeveloped root and insufficient bone support. Early eruption of a permanent tooth can cause several complications such as chronic trauma, pain, edema, an increased rate of premolar impaction and tooth displacement and/or rotation. Therefore, when a permanent tooth erupts earlier than its normal eruption period with accompanying symptoms, appropriate treatments should be done as soon as possible. A female patient of age 7 without any systemic disease was referred from a local dental clinic with chief complaint of severe mobilities and pain in both upper first premolars. According to the clinical and radiographic examinations, the permanent teeth erupted earlier with barely formed roots, severe mobilities, edema, and pain. This case is to report the successful accomplishment of root formations and stabilization of teeth after applying intraoral fixed appliances using bands and spurs for 14 months.

• The korean journal of orthodontics
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• v.34 no.4 s.105
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• pp.333-342
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• 2004

The purpose of this study was to evaluate the clinical effectiveness of a plasma arc light and light emitting diode (LED), compared with shear bond strength and the failure pattern of brackets bonded with visible light in direct bonding. Brackets were bonded with Transbond XT to 60 human premolars embedded in the resin blocks according to different light-curing methods. Then, the shear bond strength of each group was measured using a universal testing machine (Instron) and the adhesive failure pattern after debonding was visually examined by light microscope. The results were as follows: 1. The shear bond strength showed no significant difference between the visible light and light emitting diode, but the plasma arc light exhibited a significantly lower shear bond strength compared with the visible light and light emitting diode. 2. In the visible light and light emitting diode, adhesive failure patterns were similar. Bond failure occurred more frequently at the enamel-adhesive interface. 3. The bonding failure of brackets bonded with plasma arc light occurred more frequently at the bracket-adhesive interface. The results of this study suggest that plasma arc light, light emitting diode and visible light are all clinically useful in the direct bonding of orthodontic brackets.

• Journal of Dental Rehabilitation and Applied Science
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• v.37 no.1
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• pp.48-60
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• 2021

Patients who have extruded anterior teeth and deep bite with pathologic tooth migration, it is necessary not only periodontal treatment for reduce inflammation, but also orthodontic treatment for intrusion of anterior teeth. However, it is difficult to place the orthodontic brackets due to the deep bite, and there is a problem that the extrusion of the posterior teeth occurs more easily than the intrusion of the anterior teeth biomechanically. In particular, in patients with long face, relative intrusion of the anterior teeth by extrusion of the posterior teeth causes the clockwise rotation of the mandible and makes the facial profile worse. Therefore the biomechanical consideration and appliance design that can block these problems are required from the treatment plan. This is a patient who had a deep overbite with extruded anterior teeth, treated by periodontal treatment and intrusion of mandibular anterior teeth using cute brackes and miniscrews, and resulted in favorable maintenance during 8-year retention.

• The korean journal of orthodontics
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• v.19 no.1 s.27
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• pp.21-44
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• 1989

Incipient changes of the periodontal tissue in the pressure zones of rat molar subjected to the experimental force were studied by the transmission electron microscope. Experimental animals were consisted in 3 control and 21 experimental rats, of which one maxillary first molar was moved buccally with a fixed appliance which were exerting the force of 15 gm. After experimental period of 1 hour, 3 hours, 6 hours, 24 hours, 2 days, 3 days and 7 days, the animal were sacrificed with cardiac perfusion of $2.5\%$ glutaraldehyde in the sodium cacodylate buffer and the experimental teeth with surrounding periodontal structures were processed for electron microscope. At the beginning of the tooth movement, periodontal ligaments of the pressure were compressed and collagenous fibers were arranged parallel to the root of the teeth and cell free zones in company with cell necrosis were followed. Cell free zones at the periodontal ligaments appeared in the 3 hour survival group, and getting severe with time lapse it became widespread in 2-3 day survival group and undermining bone resorption as a healing process was observed in 7 day survival group. Dilatation of mitochondria and swelling of the rER in the fibroblast and other connective tissue cells in the periodontal ligament were observed in the 3 hour survival group, which were characteristics of the incipient changes in the compressed periodontal ligament. Dilatation of nuclear membrane and pyknosis were followed by the destruction of the nucleus and cell membrane. There were no evidence in cell damage or necrosis of the alveolar bone adjacent to the hyalinized area of periodontal ligaments.

• The korean journal of orthodontics
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• v.16 no.1
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• pp.51-70
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• 1986

Parathyroid hormone (PTH) is known to exert its effects on bone cells through the mediation of adenosine 3', 5'-monophosphate (cAMP). Orthodontic forces have also been shown to alter the cAMP content of paradental cells, particularly the alveolar bone osteoblasts. The objective of this experiment was to determine whether a combined orthodontic treatment-PTH administration regimen would have an additive effect on cAMP content in paradental cells in sites of periodontal ligament (PDL) tension. Seven groups of 4 one year old female cats each were treated for 1,3,6,12,24 h, 7 and 14 d by tipping one maxillary canine. PTH was administered twice daily, 30u/kg. Maxillary horizontal sections were stained immunohistochemically for cAMP and the degree of cellular staining intensity was determined microphotometrically as per cent light transmittance at 600nm. Alveolar bone osteoblasts, progenitor cells, PDL fibroblasts and cementoblasts in tenion sites were measured and the data were analyzed statistically by a mixed model analysis of variance. PTH administration increased the cAMP staining of nonorthodontically treated paradental cells in comparison to cells untreated by force or hormone. Cells in PDL tension sites of PTH-treated cats demonstrated significantly darker cAMP staining than cells in non-orthodontically-treated sites. Osteoblasts demonstrated the greatest response in terms of cAMP elevation, while in PDL fibroblasts orthodontic force did not increase cAMP levels above those measured in non-stretched hormonally-treated cells. These results demonstrate that PTH increases cAMP levels in paradental cells, particullarly in osteoblasts, and that the effects of PTH and orthodontic forces on paradental target cells may approach additivity.

• The korean journal of orthodontics
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• v.31 no.2 s.85
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• pp.271-281
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• 2001

The Purpose of this study was fourfold - to evaluate the general laws of friction applied to orthodontic conditions, to compare archwire materials under these controlled conditions, to compare ligation method, and to measure the effect of the artificial saliva on friction with these materials Three wire alloys (Cobalt-chromium, Nickel-titanium, Beta-titanium) in two size wires (.016" , .016" ${\times}$.022" ) were examined respect to the bracket (.018" ${\times}$.025" standard), and two ligature material (stainless steel, elastomeric) in dry and wet conditions The results were as follows, 1. The order of frictional force against alloy materials was Co-Cr (lowest), Ni-Ti, and ${\beta}$-Ti(highest) - with the exception of elastomeric ligation under wet conditions. 2. S.S. ligation gave rise to significantly greater friction than elastomeric ligation did. 3. Testing in the presence of saliva, rather than in dry conditions, decreased the frictional force for S.S. ligation with .016" Co-Cr, Ni-Ti, ${\beta}$-Ti. but, increased the frictional force for S.S. ligation with .016" ${\times}$ .022" Co-Cr, Ni-Ti, ${\beta}$-Ti. 4. .016" ${\times}$.022 " wire generated more friction than .016" wire.

• The korean journal of orthodontics
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• v.40 no.4
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• pp.250-259
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• 2010

Objective: Intraoral noncompliance upper molar distalization techniques have gained in popularity and have subsequently found to be successful in Class II correction. The aim of the present study was to introduce a screw supported intraoral distalization appliance and investigate its efficiency. Methods: Twenty-one subjects (11 females, 10 males; average age of 14.9 years) with Angle Class II malocclusion participated in this study. Two screws were inserted behind the incisive foramen and immediately loaded to distalize the upper first molars. An intraoral screw supported distalization appliance was used to distalize the upper molars in order to achieve a Class I molar relationship. Skeletal and dental changes were evaluated using cephalometric and three-dimensional (3D) model analysis. Results: Upper molars were distalized 3.95 mm on average and a Class I molar relationship was achieved without any anchorage loss. The upper molars were tipped only $1.49^{\circ}$ and the upper right and left molars were rotated only $0.54^{\circ}$ and $0.74^{\circ}$ respectively which were statistically non-significant (p > 0.05). Conclusions: The newly designed screw supported noncompliance distalization appliance was found to be an effective device for achieving bodily molar distalization without any anchorage loss.

• The korean journal of orthodontics
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• v.30 no.4 s.81
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• pp.387-398
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• 2000

This study was aimed to observe the effect of Anterior J hook headgear on the craniofacial structures in mixed dentition with Class II malocclusion. The laterial cephalograms of 20 children treated by Anterior J hook headgear were traced, digitized and statistically analyzed. The results were as follows : 1. Forward growth of maxilla was inhibited. 2. Rotational effect of maxilla was not observed. 3. There was distal movement of maxillary dentition. 4. Maxillarly_dentoalveolar growth changes were more effective in anterior portion than posterior portion. 5. Mandible maintained a normal growth and mandibular plane angle was maintained during treatment period. 6. The ratio of anterior facial height to posterior facial height was almostly not changed.

• The korean journal of orthodontics
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• v.34 no.5 s.106
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• pp.458-464
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• 2004

Anchorage plays an important role in orthodontic treatment especially in the maxillary arch. In spite of many efforts for anchorage control. it was difficult for clinicians to predict the result of treatment because most of the treatment necessitated an absolute compliance of patients, But recently, skeletal anchorage has been used widely because it does not necessitate patient compliance but produces absolute anchorage. In addition titanium miniscrews have several advantages such as ease of insertion and removal. possible immediate leading and use in limited implantation spaces. In this case, a skeletal Class I bialveolar protrusion Patient was treated with standard edgewise mechanics using indirect active P.S.A. (palatal skeletal anchorage). The miniscrews in the paramedian area of the hard palate provided anchorage for retraction of the upper anterior teeth and remained firm and stable throughout treatment This indicates that the PSA can be used to reinforce anchorage for orthodontic treatment in the maxillary arch Consequently, this new approach can help effective tooth movement without patient compliance, when used with various transpalatal arch systems.

• 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.