• The Journal of Korean Academy of Prosthodontics
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• v.38 no.5
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• pp.659-674
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• 2000

A large increase in the use of thin film coating of hydroxyapatite(HA) in implant dentistry is driven by the desire to take advantage of the excellent biocompatibility and high strength of HA coating. The purpose of this study was to evaluate the effects of HA-coated implants by ion Beam Assisted Deposition(IBAD) method in comparison to the sand-blasted and machined surfaces. Osteoblast culture test, removal torque test and histomorphometric analysis were performed and the following results obtained; 1. Examination of the osteoblast cultures displayed no difference in the secretion of alkaline phosphatase between the various specimen, but IBAD with pure HA specimen showed low alkaline phosphatase secretion(p<0.05). 2. Removal torque tests showed HA-coated implants by IBAD method to be similar in high value to the implants with sand-blasted surface than the implants with machined surface. And the ovariectomized group showed low mechanical test value than the normal group(p<0.05). 3. Histomorphometrical comparisons were performed on undecalcified ground sections. HA-coated implants by IBAD method demonstrated the highest mean bone-to-metal contact ratio on all threads and 3-best consecutive threads, and the implants with sand-blasted surface and implants with machined surface was in the next consecutive order(p<0.05). HA-coated implants showed slightly higher bone-to- metal contact ratio than sand-blasted implants, but no statistically significant difference was obtained between the two materials. The ovariectomized group showed lower value of bone-to-metal contact ratio than the normal group, but no statistically significant difference was obtained between the two groups. 4. Evaluation of bone volume on all threads and 3-best consecutive threads showed no statistically significant difference among the different surface treatment groups, but showed lower bone volume in ovariectomized group than in the normal group(p<0.05). According tn these results, thin film coated implants with HA showed high bone contact ratio, bone volume and removal torque strength in the short term, but long term observation is needed.

• Journal of Periodontal and Implant Science
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• v.42 no.5
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• pp.173-178
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• 2012

Purpose: The main purpose of this study was to investigate bone thickness on the buccal and palatal aspects of the maxillary canine and premolars using cone-beam computed tomography (CBCT). The differences between left- and right-side measurements and between males and females were also analyzed. Methods: The sample consisted of 20 subjects (9 males and 11 females; mean age, $21.9{\pm}3.0$) selected from the normal occlusion sample data in the Department of Orthodontics, The Catholic University of Korea. The thickness of the buccal and palatal bone walls, perpendicular to the long axis of the root were evaluated at 3 mm and 5 mm apical to cemento-enamel junction (CEJ) and at root apex. Results: At the canines and first premolars regions, mean buccal bone thickness of at 3 mm and 5 mm apical to CEJ were less than 2 mm. In contrast, at the second premolar region, mean buccal bone thickness at 3 mm and 5 mm apical from CEJ were greater than 2 mm. Frequency of thick bone wall (${\geq}2mm$) increased from the canine to the second premolar. Conclusions: This result should be considered before tooth extraction and planning of rehabilitation in the canine and premolar area of maxilla. Careful preoperative analysis with CBCT may be beneficial to assess local risk factors and to achieve high predictability of success in implant therapy.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.9
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• pp.126-134
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• 2008

Kendo is one of the popular sports in modem life. Head, wrist and thrust attack are the fast skill to get a score on a match. Human muscle skeletal model was developed for biomechanical study. The human model was consists with 19 bone-skeleton and 122 muscles. Muscle number of upper limb, trunk and lower limb part are 28, 60, 34 respectively. Bone was modeled with 3D beam element and muscle was modeled with spar element. For upper limb muscle modelling, rectus abdominis, trapezius, deltoideus, biceps brachii, triceps brachii muscle and other main muscles were considered. Lower limb muscle was modeled with gastrocenemius, gluteus maximus, gluteus medius and related muscles. The biomechanical stress and strain analysis of human muscle was conducted by proposed human bone-muscle finite element analysis model under head, wrist and thrust attack for kendo training.

• Imaging Science in Dentistry
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• v.37 no.3
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• pp.171-180
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• 2007

The role of radiographic imaging in determining the size, numbers and the position of implants is very important. To perform the implant procedure, the dentist needs to evaluate the bone pathology and bone density, and to know the precise height, width, and contour of the alveolar process, as well as its relationship to the maxillary sinus and mandibular canal. The author analyzed 3 implant cases for treatment planning with the cone beam CT. All axial, panoramic, serial and buccolingual-sectioned images of 3 cases with stent including vertical marker were taken by using Mercuray (Hitachi, Japan). When the curved line drawn intentionally did not include dot image of a vertical marker on the axial image of CBCT, the image of the vertical marker was deformed on its buccolingually sectioned image. There was wide discrepancy in inclination between the alveolar bone and tooth on buccolingually sectioned image.

• Imaging Science in Dentistry
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• v.48 no.2
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• pp.131-137
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• 2018

Cemento-osseous dysplasia (COD) is a benign fibro-osseous lesion of bone, in which normal bone is replaced by fibrous tissue, followed by calcification with osseous and cementum-like tissue. COD is classified into 3 categories according to its location: periapical, focal, and florid COD (FCOD). On radiography, FCOD appears radiolucent in its early stages. As it matures, radiopacities appear within the lesion, causing them to show a mixed appearance of radiolucency and radiopacity. Because FCOD is usually asymptomatic and grows in a self-limited manner, it does not require treatment. Secondary infection is the most frequent cause of symptomatic cases. We report a case of FCOD with symptoms that appeared after a dental restoration procedure and persisted after repeated operations. The purpose of this report is to emphasize the importance of thorough radiological evaluations of patients with FCOD before treatment.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.1
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• pp.83-89
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• 2010

Purpose: The Wide Beam Reconstruction (WBR) algorithms that UltraSPECT, Ltd. (U.S) has provides solutions which improved image resolution by eliminating the effect of the line spread function by collimator and suppression of the noise. It controls the resolution and noise level automatically and yields unsurpassed image quality. The aim of this study is WBR of whole body bone scan in usefulness of clinical application. Materials and Methods: The standard line source and single photon emission computed tomography (SPECT) reconstructed spatial resolution measurements were performed on an INFINA (GE, Milwaukee, WI) gamma camera, equipped with low energy high resolution (LEHR) collimators. The total counts of line source measurements with 200 kcps and 300 kcps. The SPECT phantoms analyzed spatial resolution by the changing matrix size. Also a clinical evaluation study was performed with forty three patients, referred for bone scans. First group altered scan speed with 20 and 30 cm/min and dosage of 740 MBq (20 mCi) of $^{99m}Tc$-HDP administered but second group altered dosage of $^{99m}Tc$-HDP with 740 and 1,110 MBq (20 mCi and 30 mCi) in same scan speed. The acquired data was reconstructed using the typical clinical protocol in use and the WBR protocol. The patient's information was removed and a blind reading was done on each reconstruction method. For each reading, a questionnaire was completed in which the reader was asked to evaluate, on a scale of 1-5 point. Results: The result of planar WBR data improved resolution more than 10%. The Full-Width at Half-Maximum (FWHM) of WBR data improved about 16% (Standard: 8.45, WBR: 7.09). SPECT WBR data improved resolution more than about 50% and evaluate FWHM of WBR data (Standard: 3.52, WBR: 1.65). A clinical evaluation study, there was no statistically significant difference between the two method, which includes improvement of the bone to soft tissue ratio and the image resolution (first group p=0.07, second group p=0.458). Conclusion: The WBR method allows to shorten the acquisition time of bone scans while simultaneously providing improved image quality and to reduce the dosage of radiopharmaceuticals reducing radiation dose. Therefore, the WBR method can be applied to a wide range of clinical applications to provide clinical values as well as image quality.

• The Journal of Korean Academy of Prosthodontics
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• v.43 no.6
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• pp.736-744
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• 2005

Statement of problem. Initial stability of implant is an important factor for predicting osseointegration. It requires a rapid, non-invasive, user-friendly technique to frequently assess the implant stability and the degree of osseointegration. Purpose. The aim of this study was to evaluate the correlation between the resonance frequency analysis (RFA) and the radiographic method for peri-implant bone change under in vitro conditions. Material and Method. Twenty implants of 3.75 mm in diameter(Neoplant, Neobiotech, Korea) were used. To simulate peri-implant bone change, 2 mm-deep $45^{\circ}$ range horizontal defect and 2 mm-deep $90^{\circ}$ range horizontal defect area were serially prepared perpendicular to the X-ray beam after conventional implant insertion. Customized film holding device was fabricated to standardize the projection geometry for serial radiographs of implants and direct digital image was obtained. ISQ values and gray values inside threads were measured before and after peri-implant bone defect preparation. Results. Within a limitation of this study, ISQ value of resonance frequency analysis was changed according to peri-implant bone change (p<0.05) and gray value of radiographic method was changed according to peri-implant bone change (p<0.05). There was no correlation between the ISQ value and the gray value for peri-implant bone change (p>0.05). But, in horizontal defect condition, relatively positive correlation were between ISQ and gray values(r=0.663). Conclusion. This results provided a possibility that peri-implant bone change may be evaluated by both RFA and radiographic method.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.44 no.4
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• pp.167-173
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• 2018

Objectives: Classification of the degree of postoperative nerve damage according to contact with the mandibular canal and buccal cortical bone has been studied, but there is a lack of research on the difference in postoperative courses according to contact with buccal cortical bone. In this study, we divided patients into groups according to contact between the mandibular canal and the buccal cortical bone, and we compared the position of the mandibular canal in the second and first molar areas. Materials and Methods: Class III patients who visited the Dankook University Dental Hospital were included in this study. The following measurements were made at the second and first molar positions: (1) length between the outer margin of the mandibular canal and the buccal cortical margin (a); (2) mandibular thickness at the same level (b); (3) Buccolingual $ratio=(a)/(b){\times}100$; and (4) length between the inferior margin of the mandibular canal and the inferior cortical margin. Results: The distances from the canal to the buccal bone and from the canal to the inferior bone and mandibular thickness were significantly larger in Group II than in Group I. The buccolingual ratio of the canal was larger in Group II in the second molar region. Conclusion: If mandibular canal is in contact with the buccal cortical bone, the canal will run closer to the buccal bone and the inferior border of the mandible in the second and first molar regions.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.39
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• pp.2.1-2.6
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• 2017

Background: All clinicians are aware of the difficulty of installing a dental implant in posterior maxilla because of proximate position of maxillary sinus, insufficient bone width, and lower bone density. This study is to examine which factors will make the implantation in the posterior maxilla more difficult, and which factors will affect the postoperative implant stability in this region. Methods: Five hundred seventy-three fixtures on the maxilla posterior were included for this study from all the patients who underwent an installation of the dental implant fixture from January 2010 to December 2014 at the Department of Oral and Maxillofacial Surgery in Pusan National University Dental Hospital (Yangsan, Korea). The postoperative implant stability quotient (ISQ) value, fixture diameter and length, presence of either bone graft or sinus lift, and graft material were included in the reviewed factors. The width and height of the bone bed was assessed via preoperative cone beam CT image analysis. The postoperative ISQ value was taken just before loading by using the OsstellTM $mentor^{(R)}$ (Integration Diagnostics AB, Gothenburg, Sweden). The t test and ANOVA methods were used in the statistical analysis of the data. Results: Mean ISQ of all the included data was 79.22. Higher initial bone height, larger fixture diameter, and longer fixture length were factors that influence the implant stability on the posterior edentulous maxilla. On the other hand, the initial bone width, bone graft and sinus elevation procedure, graft material, and approach method for sinus elevation showed no significant impact associated with the implant stability on the posterior edentulous maxilla. Conclusions: It is recommended to install the fixtures accurately in a larger diameter and longer length by performing bone graft and sinus elevation.

• Imaging Science in Dentistry
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• v.51 no.2
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• pp.175-185
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• 2021

Purpose: The primary objective of this study was to analyze the thickness and height of alveolar bone around the maxillary and mandibular incisors. Additionally, this study aimed to compare bone parameters between Caucasian (CC) and African American (AA) female patients. Materials and Methods: In this retrospective pilot study, 50 female subjects(25 CC and 25 AA) were included. The inclusion criteria were AA or CC women between the ages of 18 and 50 with a normo-divergent facial pattern and Angle's class I, end-on class II, or mild class III malocclusion. The distance from the cementoenamel junction (CEJ) to the buccal and lingual alveolar crest; the alveolar ridge thickness at the mid-root and apex; and the buccal and lingual bone thickness at 3, 6, and 9mm from the CEJ were measured. Results: No significant difference was found (P>0.05) in the cortical bone thickness at 3mm, 6mm, or 9mm from the alveolar crest between CC and AA populations for most measurements. A significant difference in bone thickness was found (P<0.05) for the lingual surface of the central incisor, with maxillary bone thickness found to be higher than mandibular bone thickness. The measurements of lingual thickness were larger than those of buccal thickness for both races. Conclusion: There were no differences in maxillomandibular anterior alveolar bone measurements between normo-divergent adult AA and CC women, except for a few parameters at varying locations. However, future studies can be planned based the current pilot study data, which may provide valuable information.