• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.8 s.227
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• pp.1237-1244
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• 2004

The orthodontic surgery including lingual orthodontics has recently attracted a person's attention due to its functional and esthetic appreciation. The skeletal anchorage with the miniscrew is newly adopted in the lingual orthodontics to assist the upholding ability. The appliciation needs to understand the mechanism of the orthodontic appliance and its related orthodontic correction for optimal orthodontic treatment. There is, however, few information about the qualitative and quantitative effect of the orthodontic appliance with the miniscrew has not been well identified. In this paper, three dimensional finite element analysis is introduced to the lingual orthodontics in order to investigate the effect of the anterior retraction force on the miniscrew and transpalatal arch wire. The analysis determines the adequate location of the miniscrew and the point of force application of the anchorage system in the lingual orthodontics. The analysis results demonstrate the effect of the position of the miniscrew and the transpalatal arch wire on the lingual orthodontics.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.198-203
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• 2004

In these days, the orthodontic surgery including lingual orthodontics has attracted a person' attention due to its functional and esthetic appreciation. The delivery of the optimal orthodontic treatment is greatly influenced by clinician' ability to predict and control the tooth movement by applying force system to dentition. The skeletal anchorage system with the miniscrew has been used recently in the lingual orthodontics to assist the anchorage control. Precise understanding of the force system produced from the various orthodontic appliances is necessary. However, the qualitative and quantitative effect of the miniscrew has not been identified well. In this paper, three dimensional finite element analysis is introduced on the lingual orthodontics to investigate the effect of anterior retraction force on the miniscrew and transpalatal arch wire. The purpose of this study is to determine the location of the miniscrew and the point of force application of the anchorage system in the lingual orthodontics. The analysis results indicate the efficient position of the miniscrew and the transpalatal arch wire in the lingual orthodontics.

• The korean journal of orthodontics
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• v.36 no.1 s.114
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• pp.30-44
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• 2006

This study was performed to investigate the location of the ideal bracket positioning plane in lingual orthodontics using the three-dimensional finite element method. Displacement of the anterior teeth were evaluated according to the vertical and the angular movements of the bracket positioning plane. To achieve the ideal movement of anterior teeth in the lingual central plane, the location of the force application point and the amount of the moment applied to the four incisors were evaluated. As the bracket positioning plane was moved parallel toward the incisal edge, uncontrolled tipping and extrusion of the maxillary and the mandibular incisors were increased. But lingual tipping of the crown was decreased in the maxillary and the mandibular canines. As the bracket positioning plane was inclined toward the incisal edge, lingual tipping was increased in the 6 anterior teeth and extrusion of incisors and intrusion of the canine was also increased. As the retraction hook of the canine bracket was elongated, lingual tipping and extrusion of the central incisor and mesial movement and extrusion of the lateral incisor were increased. In the canine, mesial and labial movements of the crown were increased. When the moment was applied to the 4 incisors of the maxillary and the mandibular arch in the lingual central plane, 280 gf-mm in the maxillary central incisor, 500 gf-mm in the maxillary lateral incisor, 170 gf-mm in the mandibular central incisor and 370 gf-mm in the mandibular lateral incisor produced bodily movement of the individual tooth.

• The korean journal of orthodontics
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• v.52 no.3
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• pp.220-235
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• 2022

Objective: To evaluate the available evidence regarding the clinical effectiveness of different types of anchorage devices. Methods: A comprehensive literature search of different electronic databases was conducted for systematic reviews investigating different anchorage methods published up to April 15, 2021. Any ongoing systematic reviews were searched using PROSPERO, and a grey literature search was undertaken using Google Scholar and OpenGrey. No language restriction was applied. Screening, quality assessment, and data extraction were performed independently by two authors. Information was categorized and narratively synthesized for the key findings from moderate- and high-quality reviews. Results: Fourteen systematic reviews were included (11 were of moderate/high quality). Skeletal anchorage with miniscrews was associated with less anchorage loss (and sometimes with anchorage gain). Similarly, skeletal anchorage was more effective in retracting anterior teeth and intruding incisors and molars, resulting in minor vertical skeletal changes and improvements in the soft tissue profile. However, insufficient evidence was obtained for the preference of any anchorage method in terms of the duration of treatment, number of appointments, quality of treatment, patient perception, or adverse effects. The effectiveness of skeletal anchorage can be enhanced when: directly loaded, used in the mandible rather than the maxilla, used buccally rather than palatally, using dual rather than single miniscrews, used for en-masse retraction, and in adults. Conclusions: The level of evidence regarding anchorage effectiveness is moderate. Nevertheless, compared to conventional anchorage, skeletal anchorage can be used with more anchorage preservation. Further high-quality randomized clinical trials are required to confirm these findings.

• The korean journal of orthodontics
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• v.44 no.2
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• pp.88-95
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• 2014

Objective: The purpose of this study was to compare the treatment duration and dentoskeletal changes between two different anchorage systems used to treat maxillary dentoalveolar protrusion and to examine the effectiveness of en-masse retraction using two miniscrews placed in the midpalatal suture. Methods: Fifty-seven patients (9 men, 48 women), who had undergone level anchorage system treatment at Aichi-Gakuin University Dental Hospital (Nagoya, Japan) were divided into two groups according to the method of maxillary posterior anchorage reinforcement: midpalatal miniscrews (25 patients, mean age 22 years) and conventional anchorage (32 patients, mean age 19 years). The en-masse retraction period, overall treatment duration, pre-treatment effective ANB angle, and change in the effective ANB angle were compared with an independent-samples t -test. Results: Compared to the headgear group, the duration of en-masse retraction was longer by approximately 4 months in the miniscrew group (p < 0.001). However, we found no significant difference in the total treatment duration between the groups. Moreover, a greater change in the effective ANB angle was observed in patients treated with miniscrews than in those treated with the conventional method (p < 0.05). Conclusions: The level anchorage system treatment using miniscrews placed in the midpalatal area will allow orthodontists more time to control the anterior teeth during en-masse retraction, without increasing the total treatment duration. Furthermore, it achieves better dentoskeletal control than does the conventional anchorage method, thereby improving the quality of the treatment results.

• The korean journal of orthodontics
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• v.29 no.2 s.73
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• pp.165-181
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• 1999

Treatment mechanics should be individualized to be suitable for each patient's personal teeth and anatomic environment to get a best treatment result with the least harmful effects to teeth and surrounding tissues. Especially, the change of biomechanical reaction associated with that of the centers of resistance of teeth should be considered when crown-to-root ratio changed due to problematic root resorption and/or periodontal disease during adult orthodontic treatment. At the present study, in order to investigate patterns of initial displacements of anterior teeth under certain orthodontic force when crown-to-root ratio changed in not only normal periodontal condition but also abnormal periodontal and/or teeth condition, the changes of the centers of resistance for maxillary and mandibular 6 anterior teeth as a segment were studied using the laser reflection technique, the lever & pulley force applicator and the photodetector with these quantified variables reducing alveolar bone 2mm by 2mm for each of maxillary 6 anterior teeth until the total amount of 8mm and root 2mm by 2mm for each of mandibular 6 anterior ones until the total amount of 6mm. The results were as follows: 1. Under unreduced condition, the center of resistance during initial displacement of maxillary 6 anterior teeth was located at the point of about $42.4\%$ apically from cemento-enamel junction(CEJ) of the averaged tooth of them and kept shifting to about $76.7\%$ with alveolar bone reduction. 2. The distance from the averaged alveolar crest level of maxillary 6 anterior teeth to the center of resistance for the averaged tooth of them kept decreasing with alveolar bone reduction, but the ratio to length of the averaged root embedded in the alveolar bone was stable at around $33\%$ regardless of that. 3. Under unreduced condition, the center of resistance during initial displacement of mandibular 6 anterior teeth was located at the Point of about $43\%$ apically from CEJ of the averaged tooth of them and this ratio kept increasing to about $54\%$ with root reduction. But the distance from CEJ to the center of resistance decreased from around 5.3mm to around 3.3mm, that is to say, the center of resistance kept shifting toward CEJ with the shortening of root length. 4. A unit reduction of alveolar bone had greater effects on the change of the centers of resistance than that of root did during initial Phase of each reduction. But both of them had similar effects at the middle region of whole length of the averaged root.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.34 no.4
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• pp.246-251
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• 2012

Purpose: The purpose of the study is to evaluate the effectiveness of anterior segmental osteotomy (ASO) in bimaxillary protrusion (BP) patients by comparison between the mandibular soft and hard tissue changes from orthodontic treatment and ASO. Methods: All 44 patients were diagnosed with BP in Kyung-Hee Medical Center. Orthodontic treatment with teeth extractions were underwent by 23 patients (Group A) and 21 patients underwent ASO (Group B). Mandibular soft and hard tissue changes were measured and evaluated, which were based on the vertical and horizontal reference line in lateral cephalometric radiographs. Statistical significance between the changes and correlation between each measurement were analyzed. Results: The amount of B point movement was lesser than that of the lower incisal tip (LIT) retraction, and LIT was tilted lingually in group A. The posterior movement discrepancy between LIT and B point was insignificant, and the inclination of lower incisor was not changed in group B. The soft tissues, including the lower lip, showed a posterior movement and reduction in the depth of mento-labial groove. According to the correlation analysis, the movement of the lower incisor was significantly related to the movement of the lower lip in group A, and the movement of the lower incisor was significantly related to that of the movement of lower lip, B point and Pog in group B. Conclusion: The orthodontic treatment in BP patients results in posterior tilting movement of the lower incisor, but ASO results in the bodily movement of the lower incisor. Consequently, ASO is more effective in BP cases because it ensures the controlled movement of the lower incisors.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.27 no.4
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• pp.365-371
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• 2005

In esthetic treatment of bimaxillary protrusion, it is important to move backward the anterior teeth segment. For the backward movement of the anterior teeth segment, orthodontic force and segmental osteotomy have been applied on the clinical treatment until recently. These methods caused long treatment time, anchorage loss, the possibility of root resorption and the complication followed by segmental osteotomy. Therefore, corticotomy has become a major concern lately. This research has been conducted to study the efficiency of corticotomy in the treatment of bimaxillary protrusion comparing the profile change, canine retraction velocity and space closing time. The research compared and analyzed space closing time, canine retraction velocity and profile change in two groups of patients. Both groups were formed out of patients over 18 years old who visited the department of dentistry in Hanyang University for treatments. The experimental group who was treated by corticotomy and Skeletal Anchorage System(SAS). The control group who received orthodontic treatment using SAS. The following results are produced after analyzing both groups. The significant statistic difference in space closing time has been observed in the experimental group as compared with the control group(p<0.05). In the experimental group, the significant statistic increase in canine retraction velocity was also observed(p<0.05). There was no significant difference in profile change between the control group and the experimental group(p<0.05). As a result, orthodontic treatment using corticotomy has a reasonable efficiency in space closing time as compared with the existing orthodontic treatment. Therefore, it is concluded that corticotomy with orthodontic treatment can be reasonably applied to dentofacial abnormality.

• The Journal of Korean Academy of Prosthodontics
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• v.35 no.3
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• pp.535-543
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• 1997

In order to compare the accuracy of impression technique using the addition silicone putty and improved heavy body material, impression were taken for the natural 6 maxillary anterior teeth, and for the metal mast model that has full arch shape with 4 cylindrical abutment teeth. Marginal gingiva was retracted by routine method using retraction cord, and two techniques were tried to compare the length of impression materials in the gingival sulcus. This was aimed to see the effect of viscosity and hydraulic pressure of impression materials for the subgingival impression. Impressions for the full arch-shaped metal master model were taken to compare the linear stability of the different impression materials and their related techniques. The conclusions were as belows : 1. The one-step impression technique showed longer extension of impression material in gingival sulcus than two-step impression technique. 2. High viscosity and hydraulic pressure of impression material were useful to take subgingival impression. 3. There was no statistically significant difference for the two-dimensional accuracy of impression technique, but two-step technique showed better trend than one-step technique.

• The korean journal of orthodontics
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• v.7 no.1
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• pp.31-39
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• 1977

The patient, 18-year-old girl, had a class III malocclusion with the lateral compression of the maxilla due to the premature loss of the canines, mild mandibular prognathism, and mouth breathing habit. The treatment plan consisted of 1) rapid maxillary expansion 2) a period of retention 3) extraction of the first mandibular premolars instead of surgical correction 4) completion of orthodontic treatment with multibanded system. The maxilla was separated in the midline by the application of orthopedic forces via a cemented rapid maxillary expansion device. After 18 months, She gained functional overbite-overjet relationship, good interdigitation of buccal segments, and facial harmony due to the retraction of lower anterior teeth.