• Journal of the korean academy of Pediatric Dentistry
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• v.24 no.3
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• pp.590-596
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• 1997

Ankylosis is defined as a fusion of alveolar bone with dentin and/or cementum and may occur at any time during or following active eruption. Ankylosed teeth maintain existing occlusal levels while adjacent teeth continue to erupt via deposition of alveolar bone. This may result in the clinical appearance of depression or submergence of ankylosed teeth below the occlusal plane. It is found more frequently in children of late mixed dentition and in mandibular primary molars. The problems arising from ankylosed teeth, due to their submerged positions, are elongation of the antagonist, tipping of the adjacent teeth, loss of arch length, food impaction and subsequent destruction of periodontal tissue, disturbance of succedaneous tooth eruption. The author observed several cases of ankylosed primary molars and properly managed. Following results were obtained. 1. Severe infraoccluded ankylosis results in loss of arch length and undesirable effect on eruption path of succedaneous tooth, therefore early diagnosis and management are important. 2. The teeth without problems may be examined periodically and restored in order to maintain the normal occlusal function.

• The korean journal of orthodontics
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• v.27 no.3 s.62
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• pp.445-456
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• 1997

This study was designed to examine the dental asymmetry in person with facial asymmetry and to examine the relationship between the degree of mandibular deviation and asymmetry of maxillary dental arch. The sample!, were divided to asymmetry group and normal group. The asymmetry group consisted of 21 subjects(6 males and 15 females) and their mean age was 23.5 years. The normal group consisted of 20 subjects(10 males and 10 females) and their mean age was 18.6 years. Anteroposterior, transverse position of all maxillary teeth except 3rd molars, vortical position of maxillary 1st molars, and angulation of central incisors were measured. The anterioposterior and transverse positions of teeth were measured on the maxillary dental casts, the vertical position of maxillary 1st molars and angulation of maxillary incisors were measured on posteroanterior cephalometric radiographs. The data were analyzed to examine whether significant asymmetries existed in each of the asymmetry and normal groups. The results of this study were as follows : 1. In the asymmetry group, the correlation between the degree of mandibular deviation and that of 3-dimensional dental asymmetry was not so high. 2. In the asymmetry group, the teeth in deviated side were more laterally positioned than that of undeviated side. There were differences in the anteroposterior position of maxillary 1st and 2nd molars and the angulation of maxillary central incisors. 3. In the asymmetry group, the transverse asymmetry was larger in the posterior teeth rather than in the anterior teeth and larger than the anteroposterior asymmetry.

• Journal of Yeungnam Medical Science
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• v.10 no.1
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• pp.37-47
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• 1993

It is commonly assumed that nasorespiratory function can exert a dramatic effect upon the development of the dentofacial complex. Specially, it has been stated that chronic nasal obstruction leads to mouth breathing, which causes altered tongue and mandibular positions. If this occurs during a period of active growth, the outcome is development of the "adenoid facies". Such patients characteristically manifest a vertically long lower third facial height, narrow alar bases, lip incompetence, a long and narrow maxillary arch and a greater than normal mandibular plane angle. But several authors have reported that so-called adenoid facies is not always associated with adenoids and mouth breathing, and that a particular type of dentition is not always found in mouth breathers with or without adenoids. Some authors have believed adenoids lead to mouth breathing in cases with particular facial characteristics and types of dentition. We assumed that the ability to adapt to individual's neuromuscular complex is various. So, we compared the difference of influence of mouth breathing between childrens who have different facial types. This study included 60 patients and they were divided into three groups by Rickett's facial type. Their dentition and tongue position were compared. The results are as follows. 1. There is a significant difference in arch width of upper molars between different facial types. Especially dolichofacial type patients have narrowest arch width. 2. There is a significant difference in tongue position between different facial types. Especially dolichofacial type patients have lowest positioned tongue.

• The Journal of Advanced Prosthodontics
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• v.9 no.5
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• pp.371-380
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• 2017

PURPOSE. The aim of this study is to evaluate and compare the stress distribution in Locator attachments in mandibular two-implant overdentures according to implant locations and different loading conditions. MATERIALS AND METHODS. Four three-dimensional finite element models were created, simulating two osseointegrated implants in the mandible to support two Locator attachments and an overdenture. The models simulated an overdenture with implants located in the position of the level of lateral incisors, canines, second premolars, and crossed implant. A 150 N vertical unilateral and bilateral load was applied at different locations and 40 N was also applied when combined with anterior load at the midline. Data for von Mises stresses in the abutment (matrix) of the attachment and the plastic insert (patrix) of the attachment were produced numerically, color-coded, and compared between the models for attachments and loading conditions. RESULTS. Regardless of the load, the greatest stress values were recorded in the overdenture attachments with implants at lateral incisor locations. In all models and load conditions, the attachment abutment (matrix) withstood a much greater stress than the insert plastic (patrix). Regardless of the model, when a unilateral load was applied, the load side Locator attachments recorded a much higher stress compared to the contralateral side. However, with load bilateral posterior alone or combined at midline load, the stress distribution was more symmetrical. The stress is distributed primarily in the occlusal and lateral surface of the insert plastic patrix and threadless area of the abutment (matrix). CONCLUSION. The overdenture model with lateral incisor level implants is the worst design in terms of biomechanical environment for the attachment components. The bilateral load in general favors a more uniform stress distribution in both attachments compared to a much greater stress registered with unilateral load in the load side attachments. Regardless of the implant positions and the occlusal load application site, the stress transferred to the insert plastic is much lower than that registered in the abutment.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.4
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• pp.586-591
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• 2002

Bruxism can be generally regarded as a diurnal clenching or nocturnal teeth grinding or a combination of both. Clenching of the teeth is forceful closure of the opposing dentition in a static relationship of the mandible to the maxilla, whereas grinding of the dentition is forceful closure of the opposing dentition in a dynamic maxillo-mandibular relationship as the mandibular arch moves through various excursive positions. The causes of bruxism are not yet discovered clearly, but most consistently mentioned cause is psychological stress. Bruxism can be also associated with sleep disorders, medication, and disturbances of the central nervous system. There is no permanent treatment method of bruxism, so the objectives for management of bruxism are reduction of psychological stress and treatment of signs and symptoms of bruxism by occlusal adjustment, occlusal splint, systemic medication and physical therapy. These cases report present three cases of children with bruxism. The bruxism was reduced in these patients wearing occlusal splint.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.21 no.2
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• pp.353-365
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• 1991

The author analyzed and compared tomographs with lateral oblique transcranial radiographs of 60 temporomandibular joints from 30 asymptomatic young adults. The results were as follows: 1. The mean height & width of condylar head were 6.82±1.99㎜, 11.98±1.28㎜ in tomographs and 5.41±0.79㎜, 10.67±1.28㎜ in transcranial radiographs. The mean height of articular fossa was 10.19±1.60㎜ in tomographs and 8.44±1.65㎜ in transcranial radiographs. 2. The mean width of articular fossa was 20.71 ±2.98㎜ in tomographs and 17.47±2.58㎜ in transcranial radiographs. There were significant differences in both the height and the width of articular fossa between two radiographic techniques (P<0.01). 3. In centric occlusion, the superior joint spaces were 4.28±1.09㎜, 4.18±1.28㎜, the anterior joint spaces were 2.84±1.02㎜, 2.53±0.72㎜, the posterior joint spaces were 3.11±1.19㎜, 2.66±0.89㎜ in tomographs and transcranial radiographs respectively. There were significant differences in right posterior joint spaces (P<0.05), and posterior joint spaces (P<0.05) between two radiographic techniques. 4. The condylar position in articular fossa was displaced posteroinferiorly (-0.35±4.40㎜ posteriorly, -1.55±1.24㎜ inferiorly) in tomographs and anteroinferiorly (0.45±3.77㎜ anteriorly, -1.29±1.26㎜ inferiorly) in transcranial radiographs with 1 inch opening. In maximum opening, it was displaced anteroinferiorly (5.39±3.63㎜ anteriorly, -1.22±1.67㎜ inferiorly) in tomographs and anteroinferiorly (6.35±4.00㎜ anteriorly, -0.55 ±1.98㎜ inferiorly) in transcranial radiographs. There was significant difference in superoinferior positions of both condyles with maximum opening between two radiographic techniques (P<0.05).

• Archives of Craniofacial Surgery
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• v.14 no.2
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• pp.119-123
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• 2013

Except for special situations, it is generally agreed that best results in the treatment of facial fractures is expected if reduction is done within the first 2 or 3 weeks after injury. We reduced facial bone fractures at 4 to 7 weeks after trauma. A 44-year-old female patient underwent open reduction for her right zygomaticomaxillary complex fracture at 7 weeks after injury. A 59-year-old female patient underwent surgery for the right mandible body and left parasymphysis fractures at 4 weeks after injury. Using traditional approaches, granulation tissue and callus were removed from the fracture sites, and malunited fracture lines were separated by a small osteotome. We reduced the displaced fractured zygoma and mandible to their normal anatomical positions and fixed them using titanium plates. No complications such as asymmetry, malunion, malocclusion, or trismus were seen. Unfavorable asymmetric facial contours were corrected, and we obtained good occlusion with favorable bony alignment. The functional and aesthetic outcomes were satisfactory. Through removal the callus and limited osteotomy, a successful approach to the previously fractured line was possible, and an exact correction with symmetry was obtained. This method can be a good option for obtaining good mobility and clinical results in treating delayed facial bone fractures.

• The Journal of Korean Academy of Prosthodontics
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• v.22 no.1
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• pp.85-94
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• 1984

The purpose of this study was to investigate treatment effectiveness of TENS and bite plane for bruxism and TMJ dysfunction patients. The electromyograms were made on males aged 23 to 25 with sound stomatognathic system, 5 males bruxism aged 24 to 27, and 1 male and 4 females TMJ dysfunction patients (right TMJ pain) aged 14 to 33. The electromyographic study was limited to the middle of masseter muscle and anterior temporal muscle. The electromyographic study was carried out with 8-channel EM2 (Myotronics Research Inc.) and was taken 5 mandibular positions of clinical rest position, clench intercuspal position, clench protruded, cluch right, clench left. The 2 pairs of surface electrodes were used exactly, with the ear lobe as reference point. The recording were subjected to determine the mean voltage. The results were as follows; 1. In the clinical rest position, the muscle activities of bruxism and TMJ dysfunction patients were higher than those of normal at the before treatment, but that were lower or similar to those of normal at the TENS after and after bite plane wearing. 2. In the clench I.C.P., the muscle activities of TMJ dysfunction patients were decreased as the order of the before treatment, after TENS, after occlusal bite plane wearing, but those of bruxism were irregular. 3. In the clench right and the clench left, the muscle activities of the middle of masseter muscle of the non-working side of bruxism were higher than those of the working side at the before treatment and after TENS, but the muscle activities of after occlusal bite plane wearing were similar to those of the normal. 4. In the clench right and the clench left, the muscle activities of the middle of masseter muscle and anterior temporal muscle of the working side of TMJ dysfunction patients were higher than those of non-working side as like the normal at the before treatment, after TENS, and after occlusal bite plane wearing.

• The korean journal of orthodontics
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• v.41 no.2
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• pp.112-120
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• 2011

Objective: Microscrew implants (MSls) offer many advantages, but some complications are known to occur during their insertion. One of the most commonly reported complications is root injury. Our aim was to identify factors associated with root injury and to evaluate their qualitative and quantitative values. Methods: Thirty-five orthodontists placed MSls (AbsoAnchor$AbsoAnchor^{(R)}$, Dentos Co. Ltd, Daegu, Korea) in the upper jaw of typodonts, labially between the second premolar and the first molar, in low and high vertical positions. Root contacts were counted, and distances between MSI apices and roots were measured. Fear level of the orthodontists was surveyed before and after the experiment. Wilcoxon's test, chi-square test, and Mann-Whitney test were used for statistical analysis. Results: Overall root contact rate of MSI insertion was 23.57%. The root contact rate was significantly higher in MSls inserted at $90^{\circ}$ (45.71%) than at $30^{\circ}$ (1.43%). The distance between the dental root and MSI also increased significantly in MSls inserted at $30^{\circ}$. Mean fear level before MSI insertion (4.6) significantly decreased after insertion (3.2); the causative factors were risk of injury to dental root and maxillary sinus or mandibular canal. Conclusions: Root injury is relatively rare, and oblique angulation reduces the risk of root and MSI contact.

• The korean journal of orthodontics
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• v.50 no.5
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• pp.346-355
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• 2020

The treatment of skeletal Class III malocclusion in adolescents is challenging. Maxillary protraction, particularly that using bone anchorage, has been proven to be an effective method for the stimulation of maxillary growth. However, the conventional procedure, which involves the surgical implantation of mini-plates, is traumatic and associated with a high risk. Three-dimensional (3D) digital technology offers the possibility of individualized treatment. Customized mini-plates can be designed according to the shape of the maxillary surface and the positions of the roots on cone-beam computed tomography scans; this reduces both the surgical risk and patient trauma. Here we report a case involving a 12-year-old adolescent girl with skeletal Class III malocclusion and midface deficiency that was treated in two phases. In phase 1, rapid maxillary expansion and protraction were performed using 3D-printed mini-plates for anchorage. The mini-plates exhibited better adaptation to the bone contour, and titanium screw implantation was safer because of the customized design. The orthopedic force applied to each mini-plate was approximately 400-500 g, and the plates remained stable during the maxillary protraction process, which exhibited efficacious orthopedic effects and significantly improved the facial profile and esthetics. In phase 2, fixed appliances were used for alignment and leveling of the maxillary and mandibular dentitions. The complete two-phase treatment lasted for 24 months. After 48 months of retention, the treatment outcomes remained stable.