• The korean journal of orthodontics
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• v.46 no.5
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• pp.310-322
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• 2016

Objective: The aim of this study was to determine the optimal loading conditions for pure intrusion of the six maxillary anterior teeth with miniscrews according to alveolar bone loss. Methods: A three-dimensional finite element model was created for a segment of the six anterior teeth, and the positions of the miniscrews and hooks were varied after setting the alveolar bone loss to 0, 2, or 4 mm. Under 100 g of intrusive force, initial displacement of the individual teeth in three directions and the degree of labial tilting were measured. Results: The degree of labial tilting increased with reduced alveolar bone height under the same load. When a miniscrew was inserted between the two central incisors, the amounts of medial-lateral and anterior-posterior displacement of the central incisor were significantly greater than in the other conditions. When the miniscrews were inserted distally to the canines and an intrusion force was applied distal to the lateral incisors, the degree of labial tilting and the amounts of displacement of the six anterior teeth were the lowest, and the maximum von Mises stress was distributed evenly across all the teeth, regardless of the bone loss. Conclusions: Initial tooth displacement similar to pure intrusion of the six maxillary anterior teeth was induced when miniscrews were inserted distal to the maxillary canines and an intrusion force was applied distal to the lateral incisors. In this condition, the maximum von Mises stresses were relatively evenly distributed across all the teeth, regardless of the bone loss.

• Journal of Periodontal and Implant Science
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• v.50 no.4
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• pp.226-237
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• 2020

Purpose: This study was conducted to assess the efficacy of prophylactic gingival grafting in the mandibular anterior labial area for preventing orthodontically induced gingival recession. Methods: Eight mongrel dogs received gingival graft surgery at the first (I1) and third (I3) mandibular incisors on both sides based on the following group allocation: AT group (autogenous connective tissue graft on I1), AT-control group (contralateral side in the AT group), CM group (xenogeneic cross-linked collagen matrix graft on I3) and CM-control group (contralateral side in the CM group). At 4 weeks after surgery, 6 incisors were splinted and proclined for 4 weeks, followed by 16 weeks of retention. At 24 weeks after surgery, casts were made and compared with those made before surgery, and radiographic and histomorphometric analyses were performed. Results: Despite the proclination of the incisal tip (by approximately 3 mm), labial gingival recession did not occur. The labial gingiva was thicker in the AT group (1.85±0.50 mm vs. 1.76±0.45 mm, P>0.05) and CM group (1.90±0.33 mm vs. 1.79±0.20 mm, P>0.05) than in their respective control groups. Conclusions: The level of the labial gingival margin did not change following labial proclination of incisors in dogs. Both the AT and CM groups showed enhanced gingival thickness.

• The korean journal of orthodontics
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• v.51 no.4
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• pp.282-292
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• 2021

Objective: To quantitatively analyze the effect of nicotine on orthodontic tooth movement (OTM) and bone remodeling in rats using micro-computed tomography and tartrate-resistant acid phosphatase immunostaining. Methods: Thirty-nine adult male Sprague-Dawley rats were randomized into three groups: group A, 0.5 mL normal saline (n = 9, 3 per 3, 7, and 14 days); group B, 0.83 mg/kg nicotine (n = 15, 5 per 3, 7, and 14 days); and group C, 1.67 mg/kg nicotine (n = 15, 5 per 3, 7, and 14 days). Each animal received daily intraperitoneal injections of nicotine/saline from the day of insertion of identical 30-g orthodontic force delivery systems. A 5-mm nickel-titanium closed-coil spring was applied between the left maxillary first molar (M1) and the two splinted incisors. The rate of OTM and volumetric bone changes were measured using micro-computed tomography. Osteoclasts were counted on the mesial alveolar bone surface of the distobuccal root of M1. Six dependent outcome variables, including the intermolar distance, bone volume fraction, bone mineral density, trabecular thickness, trabecular volume, and osteoclast number, were summarized using simple descriptive statistics. Nonparametric Kruskal-Wallis tests were used to evaluate differences among groups at 3, 7, and 14 days of OTM. Results: All six dependent outcome variables showed no statistically significant among group-differences at 3, 7, and 14 days. Conclusions: The findings of this study suggest that nicotine does not affect OTM and bone remodeling, although fluctuations during the different stages of OTM in the nicotine groups should be elucidated in further prospective studies.

• Journal of Korean Neurosurgical Society
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• v.59 no.3
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• pp.242-246
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• 2016

Craniosynostosis is the premature fusion of calvarial sutures, resulting in deformed craniofacial appearance. Hence, for a long time, it has been considered an aesthetic disorder. Fused sutures restrict growth adjacent to the suture, but compensatory skull growth occurs to accommodate the growing brain. The primary goal for the management of this craniofacial deformity has been to release the constricted skull and reform the distorted shape of the skull vault. However, the intellectual and behavioral prognosis of affected children has also been taken into consideration since the beginning of the modern era of surgical management of craniosynostosis. A growing body of literature indicates that extensive surgery, such as the whole-vault cranioplasty approach, would result in better outcomes. In addition, the age at treatment is becoming a major concern for optimal outcome in terms of cosmetic results as well as neurodevelopment. This review will discuss major concerns regarding neurodevelopmental issues and related factors.

• Archives of Craniofacial Surgery
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• v.19 no.2
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• pp.85-93
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• 2018

Deviated nose deformities have always been a surgical challenge, and it is essential to achieve both functional and esthetic improvements. Various techniques have evolved over time to correct deviated noses but no one method applies in all cases. Successful correction requires a complete understanding of the various surgical techniques and concepts, including the three-dimensional nasal structure and the time-related changes to surgically-treated noses.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.3-5
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• 2004

Cleft lip is one of the most common congenital deformities in craniofacial region. Despite the many reports on the outcome of various surgical techniques from individual medical centers, the evaluation of the outcome is based on the subjective observation because of lack of the objective evaluation system. Therefore, a new technique of objective and scientific evaluation for the nasal deformity of secondary cleft lip and nose deformity is critical to improve the management of the cleft patients including the decision of optimal age of operation and surgical technique as veil as evaluation of the outcome. In this study, a new method was proposed to evaluate the nasal deformity using nostril angle, distance, and area of patient images. The images were also evaluated by three expert plastic surgeons, and put into scale of 5 percentile. Measurement results were compared between the each category and the surgeon's evaluation, and coefficients of each category were statistically tested. As a result, The normalized overlap area of right and left nostrils and distance ratio between two centers of nostrils showed high coefficient with evaluations of plastic surgeons.

• Brain Tumor Research and Treatment
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• v.6 no.2
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• pp.86-91
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• 2018

Aneurysmal bone cyst (ABC) is a rare non-neoplastic bone lesion that involves mostly the long bones and vertebrae and may occur very rarely in the craniofacial bones. ABCs may occur as secondary bony pathologies in association with various benign and malignant bone tumors and with fibrous dysplasia (FD). FD is a common non-neoplastic bony pathology mostly affecting craniofacial bones. Secondary ABC occurring in craniofacial FD is extremely rare, with only approximately 20 cases reported in the literature to date. Here, we report on a case of secondary ABC in a 25-year-old woman who has had a craniofacial deformity for over 10 years and who presented to us with a rapidly growing painful pulsatile mass in the right frontal region that began over 2 months prior to admission. On thorough examination of computed tomography and magnetic resonance imaging brain scans taken at two-month interval, an aggressive, rapidly enlarging ABC, arising from the right frontal FD, was diagnosed. The patient underwent preoperative embolization followed by gross total resection of the ABC and cranioplasty. The 6-month follow up showed no recurrence of the ABC, nor was any progression of the FD noticed.

• Imaging Science in Dentistry
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• v.30 no.2
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• pp.117-122
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• 2000

Fibrous dysplasia is a benign disorder of bone consisting of intramedullary proliferation of fibrous tissue and irregularly distributed, poorly developed bone. The disease manifests itself in the monostotic form in which only one bone is involved and the polyostotic form in which multiple bones at different sites are affected. We reported a extensive case of polyostotic fibrous dysplasia with involvement of craniofacial bones, mandible, ribs and extremities. A 18-year-old man showed remarkable right facial swelling who had been treated on right femur 3 years ago with a bone graft for pathologic fracture and he recognized facial swelling 5 years ago. Extraoral radiograms and computed tomogram showed diffuse sclerosis with a ground glass appearance of the most cranial bones, facial bones. The right mandibular lesion showed very expansile lesion with mottled appearance. Bone scans showed mutifocal increased uptakes in craniofacial bones, right mandible, bilaterally in ribs, humerus, femur, tibia and characteristic varus deformity of right femur (shepherd's crook defomity). This case showed exceptionally bilateral, extensive nature of bone lesion and didn't show any features of skin pigmentation and endocrine disturbances.

• The korean journal of orthodontics
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• v.42 no.6
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• pp.297-306
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• 2012

Objective: This in vitro study was undertaken to evaluate the physical, chemical, and biological properties of commercially available metal orthodontic brackets in South Korea, because national standards for these products are lacking. Methods: Four bracket brands were tested for dimensional accuracy, (manufacturing errors in angulation and torque), cytotoxicity, composition, elution, and corrosion: Archist (Daeseung Medical), Victory (3M Unitek), Kosaka (Tomy), and Confidence (Shinye Odontology Materials). Results: The tested rackets showed no significant differences in manufacturing errors in angulation, but Confidence brackets showed a significant difference in manufacturing errors in torque. None of the brackets were cytotoxic to mouse fibroblasts. The metal ion components did not show a regular increasing or decreasing trend of elution over time, but the volume of the total eluted metal ions increased: Archist brackets had the maximal Cr elution and Confidence brackets appeared to have the largest volume of total eluted metal ions because of excessive Ni elution. Confidence brackets showed the lowest corrosion resistance during potentiodynamic polarization. Conclusions: The results of this study could potentially be applied in establishing national standards for metal orthodontic brackets and in evaluating commercially available products.

• The korean journal of orthodontics
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• v.46 no.2
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• pp.81-86
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• 2016

Objective: The aims of this study were to assess the direction and degree of lip-line cant in Korean adult orthodontic patients and to identify the effects of sex and age on changes in the cant severity. Methods: In this cross-sectional retrospective study, lip-line cant was measured in the frontal photographs of 585 Korean patients (92 men and 493 women) aged 18-48 years. The outcome variables (direction and degree of lip-line cant) were assessed in terms of predictor variables (sex, age, sagittal skeletal relationship, and menton deviation angle). Results: The direction of lip-line cant did not differ according to sex, age, or skeletal classification. Patients had $1.6^{\circ}$ of lip-line cant on average before orthodontic treatment. Middle-aged adults displayed a significant trend toward a lower degree of lip-line cant compared to younger adults (p < 0.01). Multiple linear regression analysis showed that the degree of lip-line cant was weakly negatively correlated with age (p < 0.001). Conclusions: While the direction of lip-line cant did not differ according to the parameters explored here, the degree of cant was correlated with age in adults, independent of menton deviation. Specifically, middle-aged adults tended to display significantly lower degrees of lip-line cant than did younger adults.