• Journal of Oral Medicine and Pain
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• v.39 no.4
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• pp.119-126
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• 2014

This review provides an overview of the most commonly used dental age estimation techniques which focus on radiological methods in Korean adults. The literature from 1995 through July 31, 2014, was searched, using PubMed, for publications in English language. In PubMed, the keywords 'tooth' OR 'dental' AND 'pulp' AND 'age estimation' were searched. Inclusion criteria was comprised of the following: the subjects were living adults and dental radiography (excluded computed tomography [CT] and cone-beam CT) was used to measure the pulpal size. Twenty articles that met the criteria were selected. The method of age estimation using dental radiographs for measuring pulp and tooth size was represented in all studies. The methods were assorted into three categories generally; Kvaal's, Ikeda's and Cameriere's methods. Those methods had certain limitations such as large error range and low correlation coefficient depending on populations, type of employed teeth and particular method. Various techniques and many studies have been published for age estimation from human teeth using dental radiographs, but those techniques showed various predictability and reliability. Therefore, future studies on larger samples with well-distributed age group using not only existing techniques but new techniques are necessary for deriving convincing results.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.46 no.2
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• pp.150-154
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• 2020

We present a case of osteoradionecrosis treated with leukocyte- and platelet-rich fibrin (LPRF) and surgery and followed up with clinical and tomographic investigations. A 65-year-old woman presented with pain in the posterior region of the right palate. Her medical history included cardiovascular disease and squamous cell carcinoma in the anterior region of the floor of the mouth that had been treated with intensity-modulated radiation therapy. Measurements of isodose curves showed a full dosage of 6,462.6 cGy in the anterior mandibular region, whereas that in the posterior region on the right side of the maxilla reached 5,708.1 cGy. Osteotomy was performed using rotary instruments, and debridement and placement of two LPRF membranes were also carried out. New gum tissue with no bone exposure was noted 14 days postoperatively. Tissue repair was complete, and the patient had no further complaints. During a 39-month follow-up period, the oral mucosa remained intact, and the patient was rehabilitated with a new upper denture. Since there is no consensus regarding the best protocol to treat osteoradionecrosis, LPRF might be an interesting adjuvant to a surgical approach. The use of LPRF is simple and reduces operational costs, time of handling, probability of technical failure, and associated morbidities for patients with osteoradionecrosis.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.1
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• pp.87-92
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• 2020

Adenomatoid odontogenic tumor (AOT) is a rare benign odontogenic jaw lesion. It usually occurs in the anterior maxilla and is mostly related to impacted canines in teenagers. A 3-year-old girl was referred from a local dental clinic due to delayed eruption of the right primary mandibular 2nd molar. There was no history of pain or swelling. Radiography revealed a large radiolucency lesion with radiopacities around the unerupted right primary mandibular 2nd molar. Surgical enucleation with extraction of the right primary mandibular 2nd molar and surgical biopsy were performed. Based on the clinical and radiological findings, this lesion was defined as an ameloblastic fibro-odontoma which often develops in the mandible of adolescents. However, this lesion was diagnosed as AOT from the results of the histological examination. This report aimed to present a rare case of AOT in the posterior mandibular area in a very young patient.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.373-375
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• 2002

4D CT is a dynamic volume imaging system of moving organs with an image quality comparable to conventional CT, and is realized with continuous and high-speed cone-beam CT. In order to realize 4D CT, we have developed a novel 2D detector on the basis of the present CT technology, and mounted it on the gantry frame of the state-of-the-art CT-scanner. In the present report we describe the design of the first model of 4D CT-scanner as well as the early results of performance test. The x-ray detector for the 4D CT-scanner is a discrete pixel detector in which pixel data are measured by an independent detector element. The numbers of elements are 912 (channels) ${\times}$ 256 (segments) and the element size is approximately 1mm ${\times}$ 1mm. Data sampling rate is 900views(frames)/sec, and dynamic range of A/D converter is 16bits. The rotation speed of the gantry is l.0sec/rotation. Data transfer system between rotating and stationary parts in the gantry consists of laser diode and photodiode pairs, and achieves net transfer speed of 5Gbps. Volume data of 512${\times}$512${\times}$256 voxels are reconstructed with FDK algorithm by parallel use of 128 microprocessors. Normal volunteers and several phantoms were scanned with the scanner to demonstrate high image quality.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.12
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• pp.6054-6068
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• 2017

In this paper, we defined the relative cross-sectional area of forearm cortical bone and investigated its correlation with hip bone mineral density values of total femur, femoral neck, femoral trochanter, femoral inter-trochanter and femoral ward's triangle, respectively. Based on the correlations, we established a linear transformation between the relative cross-sectional area of forearm cortical bone and each hip bone BMD. We obtained forearm images using CBCT and hip bone BMDs using dual-energy X-ray absorptiometry (DXA) for 28 subjects. We also investigated the optimal forearm region to provide the strongest correlation coefficient. We used the optimized forearm region to establish each linear transformation to estimate BMD values for total femur, femoral neck, femoral trochanter, femoral inter-trochanter and femoral ward's triangle from the relative cross-sectional area of forearm cortical bone, respectively. We observed the strong correlations with total femur (r=0.889), femoral neck (r=0.924), femoral trochanter (r=0.821), femoral inter-trochanter (r=0.867) and femoral ward's triangle (r=0.895), respectively. The strongest correlation was observed in the forearm mid-shaft regions. Our results suggest that the hip bone BMD values can be simply estimated from forearm CBCT images in a convenient sitting position without X-ray exposure on a hip including genital organs, and may be useful for screening osteoporosis.

• Journal of Periodontal and Implant Science
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• v.46 no.6
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• pp.415-425
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• 2016

Purpose: The present study investigated the impact of 2 different suture techniques, the conventional crossed mattress suture (X suture) and the novel hidden X suture, for alveolar ridge preservation (ARP) with an open healing approach. Methods: This study was a prospective randomized controlled clinical trial. Fourteen patients requiring extraction of the maxillary or mandibular posterior teeth were enrolled and allocated into 2 groups. After extraction, demineralized bovine bone matrix mixed with 10% collagen (DBBM-C) was grafted and the socket was covered by porcine collagen membrane in a double-layer fashion. No attempt to obtain primary closure was made. The hidden X suture and conventional X suture techniques were performed in the test and control groups, respectively. Cone-beam computed tomographic (CBCT) images were taken immediately after the graft procedure and before implant surgery 4 months later. Additionally, the change in the mucogingival junction (MGJ) position was measured and was compared after extraction, after suturing, and 4 months after the operation. Results: All sites healed without any complications. Clinical evaluations showed that the MGJ line shifted to the lingual side immediately after the application of the X suture by $1.56{\pm}0.90mm$ in the control group, while the application of the hidden X suture rather pushed the MGJ line slightly to the buccal side by $0.25{\pm}0.66mm$. It was demonstrated that the amount of keratinized tissue (KT) preserved on the buccal side was significantly greater in the hidden X suture group 4 months after the procedure (P<0.05). Radiographic analysis showed that the hidden X suture had a significant effect in preserving horizontal width and minimizing vertical reduction in comparison to X suture (P<0.05). Conclusions: Our study provided clinical and radiographic verification of the efficacy of the hidden X suture in preserving the width of KT and the dimensions of the alveolar ridge after ARP.

• Progress in Medical Physics
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• v.27 no.4
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• pp.189-195
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• 2016

This paper aims to verify the clinical feasibility of a custom-made film created by a laser cutting tool for End-to-End (E2E) quality assurance in robotic intensity modulated radiation therapy system. The custom-made film was fabricated from the Gafchromic EBT3 film with the size of $8^{{\prime}{\prime}}{\times}10^{{\prime}{\prime}}$ using a drawing that is identical to the shape and scale of the original E2E film. The drawing was created by using a computer aided design program with the image file, which is obtained by scanning original E2E film. Beam delivery and evaluations were respectively performed with the original film and the custom-made film using fixed-cone collimator on three tracking modes: 6D skull (6DS), Xsight spine (XS), and Xsight lung (XL). The differences between total targeting errors of the original and custom-made films were recorded as 0.17 mm, 0.3 mm, and 0.17 mm at 6DS, XS, and XL tracking modes, respectively. This indicates that the custom-made film could yield nearly equivalent results to those of the original E2E film, given the uncertainties caused by distortions during film scanning and vibrations associated with film cutting. By confirming the clinical feasibility of a custom-made film for E2E testing, it can be expected that economic efficiency of the testing will increase accordingly.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.37
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• pp.9.1-9.7
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• 2015

Background: This study are to identify the symptomatic changes and condylar stability after 2 jaw surgery without preceding treatments for Temporomandibular joints(TMJ) in class III patients with the TMJ symptoms; and to assess therapeutic effect of 2 jaw surgery and the necessity of preceding treatment for alleviation of TMJ symptoms. Methods: 30 prognathic patients with preexisting TMJ symptoms were divided into 2 groups according to presence or absence of preceding treatments before the surgery. We evaluated symptomatic changes on both TMJ by questionnaires and clinical examinations. And we reconstructed 3D cone beam computed tomography images before 2 jaw surgery, immediately after the surgery, and 6 months or more after the surgery with SimPlant software, and analyzed the stability of condylar position on 3D reconstruction model. Significances were assessed by the Wilcoxon signed rank test on SPSS ver. 20.0. Results: Both groups had favorable changes of TMJ symptoms after orthognathic surgery. And postoperative position of condyle had good stability during follow-up period. Conclusion: 2 jaw surgery without preceding treatments for TMD can have therapeutic effect for TMD patients with class III malocclusion.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.37
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• pp.25.1-25.9
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• 2015

Background: During the orthognathic surgery, it is important to know the exact anatomical location of the mandibular foramen to achieve successful anesthesia of inferior alveolar nerve and to prevent damage to the nerves and vessels supplying the mandible. Methods: Cone-beam computed tomography (CBCT) was used to determine the location of the mandibular foramen in 100 patients: 30 patients with normal occlusion (13 men, 17 women), 40 patients with skeletal class II malocclusion (15 men, 25 women), 30 patients with skeletal class III malocclusion (17 men, 13 women). Results: The distance from the anterior border of the mandibular ramus to mandibular foramen did not differ significantly among the three groups, but in the group with skeletal class III malocclusion, this distance was an average of $1.43{\pm}1.95mm$ longer in the men than in the women (p < 0.05). In the skeletal class III malocclusion group, the mandibular foramen was higher than in the other two groups and was an average of $1.85{\pm}3.23mm$ higher in the men than in the women for all three groups combined (p < 0.05). The diameter of the ramus did not differ significantly among the three groups but was an average of $1.03{\pm}2.58mm$ wider in the men than in the women for all three groups combined (p < 0.05). In the skeletal class III malocclusion group, the ramus was longer than in the other groups and was an average of $7.9{\pm}3.66mm$ longer in the men than women. Conclusions: The location of the mandibular foramen was higher in the skeletal class III malocclusion group than in the other two groups, possibly because the ramus itself was longer in this group. This information should improve the success rate for inferior alveolar nerve anesthesia and decrease the complications that attend orthognathic surgery.

• The korean journal of orthodontics
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• v.45 no.5
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• pp.236-244
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• 2015

Objective: The aim of this study was to investigate three-dimensional molar displacement after distalization via miniscrews and a horizontal modification of the trans-palatal-arch (TPA). Methods: The subjects in this clinical trial were 26 Class II patients. After the preparation of a complete set of diagnostic records, miniscrews were inserted between the maxillary 2nd premolar and 1st molar on the palatal side. Elastic modules connected to the TPA exerting an average force of 150-200 g/side parallel to the occlusal plane were applied. Cone-beam computed tomography was utilized to evaluate the position of the miniscrews relative to the adjacent teeth and maxillary sinus, and the direction of force relative to molar furcation. The distances from the central point of the incisive papilla to the mesiopalatal cusps of the 1st maxillary molars and the distances between the mesiopalatal cusps of the left and right molars were measured to evaluate displacement of the maxillary molars on the horizontal plane. Interocclusal space was used to evaluate vertical changes. Results: Mean maxillary 1st molar distalization was $2.3{\pm}1.1mm$, at a rate of $0.4{\pm}0.2mm/month$, and rotation was not significant. Intermolar width increased by $2.9{\pm}1.8mm$. Molars were intruded relative to the neighboring teeth, from 0.1 to 0.8 mm. Conclusions: Distalization of molars was possible without extrusion, using the appliance investigated. The intrusive component of force reduced the rate of distal movement.