• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.47 no.4
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• pp.315-320
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• 2021

Carbon-ion radiotherapy (CIRT) is on the rise as a treatment choice for malignant tumor. Compared to conventional radiotherapy, particle beams have different physical and biological properties. Particle beam provides a low entry dose, deposits most of the energy at the endpoint of the flight path, and forms an asymptotic dose peak (the "Bragg peak"). Compared to protons, carbon with its larger mass decreases beam scattering, resulting in a sharper dose distribution border. We report a 50-year-old male who underwent CIRT without surgical resection on osteosarcoma of the mandible. After CIRT, the patient's pain was gone, and the malignant mass remained stable with accompanying necrosis. Nine months later, however, magnetic resonance imaging demonstrated progression of the left mandibular osteosarcoma with pulmonary metastases. After multidisciplinary discussion, concurrent chemoradiotherapy was conducted. While necrotic bone segments came out of the mandible during subsequent periodic outpatient visits, the tumor itself was stable. Thirty months after his first visit and diagnosis, the patient is waiting for chemotherapy. Although CIRT is superior in treating radioresistant hypoxic disease, CIRT is in its infancy, so care must be taken for its indications and complications.

• Restorative Dentistry and Endodontics
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• v.45 no.4
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• pp.43.1-43.9
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• 2020

A variety of therapeutic modalities can be used for the endodontic treatment of a traumatized tooth with internal root resorption (IRR). The authors present a case report of the successful restoration of a traumatized upper central incisor that was weakened due to severe IRR and subsequent periapical lesion formation. A 20-year-old female patient was referred to our clinic with severe internal resorption and subsequent periapical pathosis destroying the buccal bone wall. Root canal treatment had been initiated previously at another dental practice, but at that time, the patient's condition could not be managed even with several treatments. After cone-beam computed tomography imaging and proper chemomechanical cleaning, the tooth was managed with a mineral trioxide aggregate plug followed by root canal filling using short fiber-reinforced composite, known as the Bioblock technique. This report is the first documentation of the use of the Bioblock technique in the restoration of a traumatized tooth. The Bioblock technique appears to be ideal for restoring wide irregular root canals, as in cases of severe internal resorption, because it can uniquely fill out the hollow irregularities of the canal. However, further long-term clinical investigations are required to provide additional information about this new technique.

• Imaging Science in Dentistry
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• v.50 no.2
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• pp.93-98
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• 2020

Purpose: Little is known regarding the accuracy of clinical magnetic resonance imaging (MRI) protocols with acceptable scan times in sinus graft assessment. The aim of this study was to evaluate the correlations between MRI and cone-beam computed tomographic (CBCT) measurements of maxillary sinus grafts using 2 different clinical MRI imaging protocols. Materials and Methods: A total of 15 patients who underwent unilateral sinus lift surgery with biphasic calcium phosphate were included in this study. CBCT, T1-weighted MRI, and T2-weighted MRI scans were taken 6 months after sinus lift surgery. Linear measurements of the maximum height and buccolingual width in coronal images, as well as the maximum anteroposterior depth in sagittal images, were performed by 2 trained observers using CBCT and MRI Digital Imaging and Communication in Medicine files. Micro-computed tomography (micro-CT) was also performed to confirm the presence of bone tissue in the grafted area. Correlations between MRI and CBCT measurements were assessed with the Pearson test. Results: Significant correlations between CBCT and MRI were found for sinus graft height (T1-weighted, r=0.711 and P<0.05; T2-weighted, r=0.713 and P<0.05), buccolingual width (T1-weighted, r=0.892 and P<0.05; T2-weighted, r=0.956 and P<0.05), and anteroposterior depth (T1-weighted, r=0.731 and P<0.05; T2-weighted, r=0.873 and P<0.05). The presence of bone tissue in the grafted areas was confirmed via micro-CT. Conclusion: Both MRI pulse sequences tested can be used for sinus graft measurements, as strong correlations with CBCT were found. However, correlations between T2-weighted MRI and CBCT were slightly higher than those between T1-weighted MRI and CBCT.

• Imaging Science in Dentistry
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• v.49 no.4
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• pp.295-299
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• 2019

Purpose: This clinical pilot study was performed to determine the effectiveness of dual-energy cone-beam computed tomography (DE-CBCT) in measuring bone mineral density (BMD). Materials and Methods: The BMD values obtained using DE-CBCT were compared to those obtained using calibrated multislice computed tomography (MSCT). After BMD calibration with specially designed phantoms, both DE-CBCT and MSCT scanning were performed in 15 adult dental patients. Three-dimensional (3D) Digital Imaging and Communications in Medicine data were imported into a dental software program, and the defined regions of interest (ROIs) on the 3-dimensional surface-rendered images were identified. The automatically-measured BMD values of the ROIs (g/㎤), the differences in the measured BMD values of the matched ROIs obtained by DE-CBCT and MSCT 3D images, and the correlation between the BMD values obtained by the 2 devices were statistically analyzed. Results: The mean BMD values of the ROIs for the 15 patients as assessed using DE-CBCT and MSCT were 1.09±0.07 g/㎤ and 1.13±0.08 g/㎤, respectively. The mean of the differences between the BMD values of the matched ROIs as assessed using DE-CBCT and calibrated MSCT images was 0.04±0.02 g/㎤. The Pearson correlation coefficient between the BMD values of DE-CBCT and MSCT images was 0.982 (r=0.982, P<0.001). Conclusion: The newly developed DE-CBCT technique could be used to measure jaw BMD in dentistry and may soon replace MSCT, which is expensive and requires special facilities.

• Imaging Science in Dentistry
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• v.50 no.2
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• pp.153-159
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• 2020

Purpose: This study was conducted evaluate the influence of reconstruction parameters of micro-computed tomography (micro-CT) images on bone mineral density (BMD) analyses. Materials and Methods: The sample consisted of micro-CT images of the maxillae of 5 Wistar rats, acquired using a SkyScan 1174 unit (Bruker, Kontich, Belgium). Each acquisition was reconstructed following the manufacturer's recommendations(standard protocol; SP) for the application of artifact correction tools(beam hardening correction [BHC], 45%; smoothing filter, degree 2; and ring artifact correction [RAC], level 5). Additionally, images were reconstructed with 36 protocols combining different settings of artifact correction tools (P0 to P35). BMD analysis was performed for each reconstructed image. The BMD values obtained for each protocol were compared to those obtained using the SP through repeated-measures analysis of variance with the Dunnett post hoc test(α=0.05). Results: The BMD values obtained from all protocols that used a BHC of 45% did not significantly differ from those obtained using the SP (P>0.05). The other protocols all yielded significantly different BMD values from the SP(P<0.05). The smoothing and RAC tools did not affect BMD values. Conclusion: BMD values measured on micro-CT images were influenced by the BHC level. Higher levels of BHC induced higher values of BMD.

• Journal of Korean Neurosurgical Society
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• v.30 no.12
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• pp.1381-1387
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• 2001

Objective : Endodermal sinus tumor or yolk sac tumor is an uncommon malignant germ-cell neoplasm. This tumor was originally described as a germ cell tumor of the ovary or the testis. Intracranial endodermal sinus tumor is extremely rare and usually develop in the pineal or suprasellar regions. The authors evaluated the effect of adjuvant therapy(chemotherapy combined with radiotherapy) and radical removal of intracranial endodermal sinus tumors. Material and Methods : Between 1996 and 2001, four patients of intracranial endodermal sinus tumor were diagnosed with tumor marker(AFP) and biopsy. Three patients were treated with surgical removal and chemotherapy with cisplatin($20mg/m^2$), etoposide($100mg/m^2$) and bleomycin($15mg/m^2$) as well as external beam radiation therapy. We compared the management problems for these tumors. Result : In all three patients the tumor size and the level of tumor marker decresed during initial adjuvant therapy. However, Tumors showed regrowth with elevated AFP of serum and CSF possibly related to delayed chemotherapeutic treatment or inadequate administration of chemotherapeutic drugs due to severe bone marrow suppression. An additional chemotherapy and external radiation therapy were given, but tumors could not be controlled with leptomeningeal seeding. Conclusion : Radiotherapy is considered to be less effective. The combination chemotherapy with PVB(cisplatin, vinblastine, bleomycine) or PE(cisplatin, etoposide) is considered to be value in prolongation of the survival rate. But the role of chemotherapy in this tumor has not yet been clarified due to bone marrow suppression and drug resistance. Further study with large series of this tumor is necessary to establish the optimal management.

• 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.

• The korean journal of orthodontics
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• v.50 no.3
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• pp.206-215
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• 2020

Osteochondroma is a common benign tumor of bones, but it is rare in the mandibular condyle. With its outgrowth it manifests clinically as deviation of the mandible limitation of mouth opening, and facial asymmetry. After the tumor is diagnosed on the basis of clinical symptoms and radiographic examination including cone-beam computed tomography (CBCT) analysis, an appropriate surgery and treatment plan should be formulated. Herein, we present the case of a 44-year-old female patient who visited our dental hospital because her chin point had been deviating to the left side slowly but progressively over the last 3 years and she had difficulty masticating. Based on CBCT, she was diagnosed with skeletal Class III malocclusion accompanied by osteochondroma of the right mandibular condyle. Maxillary occlusal cant with the right side down was observed, but it was confirmed to be an extrusion of the molars associated with dental compensation. Therefore, after intrusion of the right molars with the use of temporary anchorage devices, sagittal split ramus osteotomy was used to remove the tumor and perform orthognathic surgery simultaneously. During 6 months after the surgery, continuous bone resorption and remodeling were observed in the condyle of the affected side, which led to a change in occlusion. During the postoperative orthodontic treatment, intrusive force and buccal torque were applied to the molars on the affected side, and a proper buccal overjet was created. After 18 months, CBCT revealed that the rate of bone absorption was continuously reduced, bone corticalization appeared, and good occlusion and a satisfying facial profile were achieved.

• The korean journal of orthodontics
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• v.46 no.6
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• pp.345-355
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• 2016

Objective: The purpose of this study was to determine whether predicting maturation of the midpalatal suture is possible by classifying its morphology on cone-beam computed tomography (CBCT) images and to investigate relationships with other developmental age indices. Methods: The morphology of the midpalatal suture was assessed by using CBCT images of 99 patients. Axial plane images of the midpalatal suture were classified into five stages according to the classification scheme. To make the assessment more accurate, the morphology and fusion of the midpalatal suture were additionally investigated on coronal cross-sectional planar images and volume-rendered images. Bone age was evaluated using the hand and wrist method (HWM) and cervical vertebrae method (CVM); dental age (Hellman's index), sex, and chronological age were also assessed. To evaluate relationships among variables, Spearman's rho rank test was performed along with crosstabs using contingency coefficients. Results: The HWM and CVM showed strong correlations with the maturation stage of the midpalatal suture, while other indices showed relatively weak correlations (p < 0.01). Through crosstabs, the HWM and CVM showed high association values with CBCT stage; the HWM demonstrated slightly higher values (p < 0.0001). Based on the HWM, the midpalatal suture was not fused until stage 6 in both sexes. Conclusions: Among developmental age indices, the HWM and CVM showed strong correlations and high associations, suggesting that they can be useful in assessing maturation of the midpalatal suture.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.44 no.1
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• pp.18-24
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• 2018

Objectives: Foreign bodies (FBs) account for 3.8% of all pathologies of the head and neck region, and approximately one third of them are missed on initial examination. Thus, FBs represent diagnostic challenges to maxillofacial surgeons, rendering it necessary to employ an appropriate imaging modality in suspected cases. Materials and Methods: In this cross-sectional study, five different materials, including wood, metal, glass, tooth and stone, were prepared in three sizes (0.5, 1, and 2 mm) and placed in three locations (soft tissue, air-filled space and bone surface) within a sheep's head (one day after death) and scanned by panoramic radiography, cone-beam computed tomography (CBCT), and ultrasonography (US) devices. The images were reviewed, and accuracy of the detection modalities was recorded. The data were analyzed statistically using the Kruskal-Wallis, Mann-Whitney U-test, Friedman, Wilcoxon signed-rank and kappa tests (P<0.05). Results: CBCT was more accurate in detection of FBs than panoramic radiography and US (P<0.001). Metal was the most visible FB in all of modalities. US was the most accurate technique for detecting wooden materials, and CBCT was the best modality for detecting all other materials, regardless of size or location (P<0.05). The detection accuracy of US was greater in soft tissue, while both CBCT and panoramic radiography had minimal accuracy in detection of FBs in soft tissue. Conclusion: CBCT was the most accurate detection modality for all the sizes, locations and compositions of FBs, except for the wooden materials. Therefore, we recommend CBCT as the gold standard of imaging for detecting FBs in the maxillofacial region.