• The Journal of the Korean dental association
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• v.54 no.7
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• pp.563-574
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• 2016

A clear overlay appliance is a type of a removable appliance made from transparent thermoplastic plastic film that covers the entire dentition to move the teeth. It is one of the most favored orthodontic methods opted for by adult patients; this treatment is esthetic, does not cause discomfort and allows oral hygiene to be easily managed when compared to other conventional fixed treatment methods. However, the use of clear overlay appliances, such as invisalign or clear aligner, is associated with various clinical challenges. In particular, the appliances require longer treatment periods compared to fixed treatment, and due to the structural characteristics of the appliances, it is difficult to make proper posterior occlusion and certain type of tooth movement, including extrusion, rotation and tip. Thus, the clear overlay appliances are regarded as supplementary appliances by most orthodontists and have been used for simple orthodontic treatments, such as partial anterior alignments or orthodontic relapse cases. Owing to the remarkable advancement in the field of 3D digital technology over a period of 15 years, the accuracy and convenience of modern clear overlay appliances have continuously improved. Moreover, orthodontic outcomes have also been greatly improved by the introduction of new materials and successful application of various biomechanical methods from conventional orthodontic treatments in the design of clear overlay appliances. This study investigates the clinical limitations that should be considered during the application of clear overlay appliances and also examines the efforts and methods used to overcome these challenges.

• The korean journal of orthodontics
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• v.15 no.2
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• pp.291-301
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• 1985

Fifty subjects who were to be treated with fixed orhodontic appliances by light wire edgewise technique were selected. Bands with different marginal depth were made in first molar and direct bonding brackets were bonded in second premolar. For determining the effects of fixed orthodontic appliance on the gingival tissue, the changes of clinical crown length, periodontal pocket depth, gingival sulcus fluid were checked. The results were as follows: 1. Gingival condition was deteriorated after wearing the fixed orthodontic appliance, and the deteriorative rate was decreased gradually. 2. The greatest gingival change was occurred in the maxillary first molar among the experimental teeth. 3. The gingival change of maxillary teeth was greater than that of mandibular teeth. $(p\leq0.01)$ 4. The greater gingival change was occurred around subgingivally located band than around supragingivally located band. 5. Comparing the gingival changes of banded teeth with them of bonded teeth, the gingival tissue was more effected by oral hygiene than by type of appliances. 6. In the quantitive changes of gingival crevicular fluid, there was no exact relationship with gingival inflammation.

• The korean journal of orthodontics
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• v.46 no.1
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• pp.55-61
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• 2016

Skeletal anchorage-assisted upper molar distalization has become one of the standard treatment modalities for the correction of Class II malocclusion. The purpose of this study was to analyze maxillary molar movement patterns according to appliance design, with the simultaneous use of buccal fixed orthodontic appliances. The authors devised two distinct types of midpalatal miniscrew-assisted maxillary molar distalizers, a lingual arch type and a pendulum type. Fourteen patients treated with one of the two types of distalizers were enrolled in the study, and the patterns of tooth movement associated with each type were compared. Pre- and post-treatment lateral cephalograms were analyzed. The lingual arch type was associated with relatively bodily upper molar distalization, while the pendulum type was associated with distal tipping with intrusion of the upper molar. Clinicians should be aware of the expected tooth movement associated with each appliance design. Further well designed studies with larger sample sizes are required.

• Journal of dental hygiene science
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• v.11 no.6
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• pp.489-495
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• 2011

The present study was designed to grasp the oral health behavior practice levels and PHP index and gingival index of orthodontic patients' orthodontic related characteristics. A survey and oral examination were conducted for 206 orthodontic patients with fixed appliances. The collected data were analyzed with a t-test, one way ANOVA and stepwise multiple regression. Women were higher than men of the toothbrushing parts(p<0.05), toothbrushing frequency(p=0.001) and use of more oral hygiene products(p<0.01). As for the use of more oral hygiene products practice, it has higher when experience of more education(p<0.05), toothbrushing method practice difference when it comes to age(p<0.05). As for toothbrushing times, difference was purpose of orthodontics(p<0.05) and period of orthodontics(p<0.05) and orthodontics equipment(p<0.05). As for orthodontic equipment, conventional-ligating bracket high score compared to the self-ligating bracket with Buccal PHP index(p<0.001) and gingival index(p<0.05). The factors with lowest possible Buccal PHP index; when age is greater(p<0.05), toothbrushing method practice is higher(p<0.001) and when patients have self-ligating bracket(p<0.001). Education for the orthodontic patients on the oral health behavior practice should be carried out structurally to the group of patients who are 17 years old or younger, to the group with conventional-ligating bracket and to the men. Moreover, it is critical to ensure that there won't be oral health problem during on orthodontic period.

• The korean journal of orthodontics
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• v.34 no.4 s.105
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• pp.363-370
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• 2004

Patients with fixed orthodontic appliances frequently have increased levels of plaque accumulation leading to the possibility of gingivitis or enamel decalcification. Although many methods may be helpful in reducing dental plaque formation, the optimal mechanical removal of plaque is the most important factor during orthodontic treatment. The purpose of this study was to evaluate the efficacy of an electric toothbrush (with a specially designed orthodontic brush head) compared to a manual toothbrush in controlling plaque and gingivitis for patients with fixed orthodontic appliances. Oral hygiene status was measured in thirty-four patients using a plaque index, a gingival index and a bleeding index, before and four weeks after the attachment of fixed orthodontic appliances. Patients were randomly divided into two groups: electric and manual toothbrush groups. Oral hygiene instruction was given according to the type of toothbrush used. The Braun Oral-B D9511 with Braun Oral-B Ortho OD 15-1 brush head was used as the electric toothbrush while the Butler G.U.M. 124 was given as the manual toothbrush. After four md eight weeks, oral hygiene status was measured again. Through a comparison between the electric and the manual toothbrush groups, the following results were obtained. 1. All oral hygiene indices showed an increasing tendency after four weeks of fixed orthodontic appliance. 2. All indices presented a decreasing tendency four and eight weeks after oral hygiene instruction. 3. In case of the gingival index and bleeding index, the decreasing tendency did not show a statistically significant difference between the electric and the manual toothbrush groups. 4. The decreasing tendency of plaque index presented a statistically significant difference between the two groups, showing that the electric toothbrush was more effective in terms of oral hygiene. These findings suggest that an electric toothbrush is useful to orthodontic patients with fixed appliances.

• The korean journal of orthodontics
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• v.29 no.3 s.74
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• pp.361-374
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• 1999

Intraoral filled type of orthodontic appliance can cause reversible or irreversible damages such as gingivitis, periodontitis, enamel decalcification, dental caries, root resorption, and pulpal changes. Such adverse effects are brought by increase in dental plaque as well as oral flora. Such an increase causes gingival inflammation and enamel decalcification. The purpose of this study is to get klowledge on initial changes in dental plaque, gingivitis, and enamel decalcification after bonding fixed orthodontic appliances according to time flow, gender, and sides(right/left) of premolar region. For control group, 48 students of dental college, Yonsei university(26 males, 22 females) were chosen; for experimental group, 73 orthodontic patients(36 males, 37 females) who will be treated with fixed appliances were chosen. All the subjects had no systemic disease, juvenile periodontitis and all the females had passed their ,menarche. Tooth brushing instruction was given to all the subjects prior to the experiment. For control group, plaque index, gingival index, and decalcification index were measured twice at 3 weeks interval ; for experimental group, the same was done prior to, 3, 6, 9 weeks after bonding fixed appliances. The following results were obtained: 1. In plaque index 3 weeks after placement of appliances, and it showed gradual increase afterwards. 2. In gingival index3 weeks after placement of appliances, and afterwards it showed increase at a faster rate than plaque index. 3. Enamel decalcification began to show between 3 and 6 weeks after bonding fixed appliances. Decalcification index began to increase 6 weeks after appliance placement, but there was no statistical significance. 4. When the comparison was made between two sides of premolar region, the right side showed greater index in plaque and gingival index of experimental group.

• The korean journal of orthodontics
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• v.47 no.3
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• pp.207-212
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• 2017

The popularity of clear overlay retainers (CORs) has increased recently because of their advantages such as better esthetics, cost effectiveness, easy fabrication, and good compliance. However, a deficiency in posterior occlusal settling is a reported limitation of CORs. The aim of this study was to evaluate the posterior occlusal contact changes in a new type of clear orthodontic retainer called Oral-treaper (OTP), which consists of three layers and has stronger mechanical characteristics than do conventional retainers. Three patients who completed fixed orthodontic treatment received OTP as a removable retainer. Cast models were fabricated after the removal of fixed appliances (T1) and after 4 to 11 months of using the retainers (T2). We evaluated all the cast models to compare the post-orthodontic settling pattern during the use of the OTPs. The depth of occlusal contacts was evaluated using color maps. The OTP did not prevent vertical settling in all patients but resulted in an improvement in posterior occlusal contact points.

• The korean journal of orthodontics
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• v.20 no.2
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• pp.409-417
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• 1990

Tooth movement would be impeded by frictional force arised between archwire and tube, bracket or elastics in the fixed orthodontic appliances, which could be changed variably by such several factors as the contact area, normal (perpendicular) force and the condition of contact surface. There were many literatures about frictional force in the orthodontic region, but different results were obtained from little controlled research so that was very difficult in clinical application. Therefore we have reviewed comprehensively previous literatures about frictional force and thus several results were obtained as follows: 1. For use species of the orthodontic wire, frictional force was influenced mainly by surface roughness of wire in the absence of binding, while that was influenced mainly by normal force in high binding angulation. 2. For the cross-section and diameter of the wire, the contact area influenced mainly on frictional force in the absence of binding, while wire stiffness influenced mainly on frictional force in high binding angulation. 3. The greater the bracket width, the greater frictional force, and frictional force of the plastic bracket was larger than that of the metal bracket. 4. For ligation type, frictional force of the stainless steel ligation was larger than that of the elastic ligation, and frictional force was directly proportional to ligation force. 5. Variable frictional force were occured from the saliva combined with such another factors as normal force and mode of surface oxide et al.

• The korean journal of orthodontics
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• v.49 no.2
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• pp.89-96
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• 2019

Objective: The purpose of this study was to assess the long-term stability of rapid palatal expansion (RPE) followed by full fixed edgewise appliances. Methods: This study included 67 patients treated using Haas-type RPE and non-extraction edgewise appliance therapy at a single orthodontic practice. Serial dental casts were obtained at three different time points: pretreatment ($T_1$), after expansion and fixed appliance therapy ($T_2$), and at long-term recall ($T_3$). The mean duration of the $T_1-T_2$ and $T_2-T_3$ periods was $4.8{\pm}3.5years$ and $11.0{\pm}5.4years$, respectively. The dental casts were digitized, and the computed measurements were compared with untreated reference data. Results: The majority of treatment-related increases in the maxillary and mandibular arch measurements were statistically significant (p < 0.05) and greater than expected for the untreated controls. Although many measurements decreased postretention ($T_2-T_3$), the net gains persisted for all of the measurements evaluated. Conclusions: The use of RPE therapy followed by full fixed edgewise appliances is an effective method for increasing maxillary and mandibular arch width dimensions in growing patients.

• The korean journal of orthodontics
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• v.33 no.5 s.100
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• pp.381-389
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• 2003

Mutans streptococci is the major causative factor in dental caries. Especially, orthodontic patients with fixed appliance are a risk group for dental caries. Because fixed appliances attached on teeth may change the environment of dental plaque, the enamel decalcification or dental caries around the bracket and band is a major side effect of orthodontic treatmet. The aim of this study was to search plant extracts that have antimicrobial effect on mutans streptococci. Seed-extract of Casia torn were prepared with ethanol and CHMC-2032, the leaf-extracts from Camellia sinensis extract, was obtained extract, 2 type strains and 20 clinical isolates of mutans streptococci isolated from the interface between orthodontic brackets and tooth surfaces in the orthodontic patients were used in this study. The minimal inhibitory concentration of CHMC-2032 was 5mg/ml on the S. mutans KCTC 3065, S. sobrinus KCTC 3088, and 8 clinical isolates of S. sobrinus. However, there was no antibacterial effect of seed-extract of C. tora on mutans streptococci. These data suggest that green tea nay be more effective than the tea Prepared from C tora In the prevention of enamel decalcification or dental caries around brackets.