• 대한치과교정학회지
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• 제29권1호
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• pp.95-106
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• 1999

백서에서 실험적 치아 이동시 bisphosphonate가 파골세포의 형성에 미치는 영향과 골 흡수 억제기전을 규명하고 독성유무를 알아보고자 하였다. 체중 260-350g의 웅성 백서 87마리를 정상군(장치비장착 + $0.9\%$ NaCl), 대조군(장치장착 + $0.9\%$ NaCl) 및 장치장착후 bisphosphonate 투여군(0.8 mg, 4 mg, 20 mg, 및 100 mg/kg) 으로 분류하였다. 상악 좌측 제1대구치를 근심으로 치아이동이 일어나도록 50-70g의 교정력을 가하고, 교정장치 장착후 1일, 3일 및 7일째에 혈청 acid phosphatase와 lactate dehydrogenase (LDH)의 활성도를 측정하고, 또한 제1 대구치를 포함한 상악골 일부에서 파골세포수 및 골흡수 정도를 조직학적으로 관찰하여 다음과 같은 성적을 얻었다. 1. Acid phosphatase 활성도는 장치후 1일째와 3일째에 대조군과 bisphosphonate 투여군에서 모두 정상군에 비해 2-3배 높았으나, 7일째에는 정상군과 유의한 차이를 보이지 않았다. 2. LDH활성도는 bisphosphonate 4 mg과 20 mg/kg 투여군에서 전 실험기간에 걸쳐 증가된 양상을 보였으나 0.8 mg과 100 mg/kg 투여군에서는 유의한 차이를 나타내지 않았다. 3. 골흡수는 장치후 1일째에 대조군과 bisphosphonate투여군에서 모두 관찰되지 않았으나, 3일 이후에 나타나 7일째까지 지속되었다. Bisphosphonate 4, 20 및 100 mg/kg군에서의 골흡수정도는 3일째에는 대조군에 비해 미약하였으나 7일째에는 대조군과 유사하게 나타났다. 4. 파골세포는 1일째에 대조군이나 bisphosphonate투여군 모두에서 거의 관찰할 수 없었다. 3일째에 대조군에서는 파골세포가 다량 출현하였으나 bisphosphonate 투여군에서는 약물의 용량이 증가함에 따라 감소하여 나타났다. 이상의 결과로 실험적 치아이동시 파골세포의 형성억제가 bisphosphonate에 의한 골흡수 억제기전이 아님을 알 수 있었고, bisphosphonate는 투여량이 증가에 따른 뚜렷한 세포독성은 관찰되지 않았으며, 골흡수 억제효과를 지속시키기 위해서는 약물이 반복적으로 투여되어야 할 필요가 있음이 시사되었다.

• Journal of Periodontal and Implant Science
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• 제46권2호
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• pp.128-134
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• 2016

Purpose: This article describes a case of the successful non-surgical management of a periodontally compromised maxillary premolar. Methods: A combination therapy, including root planing, occlusal adjustment, and tooth splinting, was applied. Clinical and radiographic examinations were performed during the 16-month follow-up period. Results: All periodontal parameters were improved. There were dramatic decreases (3-6 mm) in the probing pocket depth, tooth mobility, and marginal bone loss. Interestingly, gradual resolution of the periapical radiolucency and alveolar bone regeneration were observed in the radiographs, and the periodontal condition was maintained during the follow-up period. Conclusions: Within the limits of this study, these results demonstrate the importance of natural tooth preservation through proper periodontal treatment and occlusal adjustment of the periodontally compromised tooth, which is typically targeted for tooth extraction and dental implantation.

• Imaging Science in Dentistry
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• 제52권2호
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• pp.171-179
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• 2022

Purpose: The aim of this study was to assess the accuracy of cone-beam computed tomographic (CBCT) images obtained using different voxel sizes in measuring trabecular bone microstructure in comparison to micro-CT. Materials and Methods: Twelve human skull bones containing posterior-mandibular alveolar bone regions were analyzed. CBCT images were obtained at voxel sizes of 0.075mm(high: HI) and 0.2mm(standard: Std), while microCT imaging used voxel sizes of 0.06 mm (HI) and 0.12 mm (Std). Analyses were performed using CTAn software with the standardized automatic global threshold method. Intraclass correlation coefficients were used to evaluate the consistency and agreement of paired measurements for bone volume (BV), percent bone volume (BV/TV), bone surface (BS), trabecular thickness (TbTh), trabecular separation (TbSp), trabecular number (TbN), trabecular pattern factor(TbPf), and structure model index (SMI). Results: When compared to micro-CT, CBCT images had higher BV, BV/TV, and TbTh values, while micro-CT images had lower BS, TbSp, TbN, TbPf, and SMI values (P<0.05). The BV, BV/BT, TbTh, and TbSp variables were higher with Std voxels, whereas the BS, TbPf, and SMI variables were higher with HI voxels for both imaging methods. For each imaging modality and voxel size evaluated, BV, BS, and TbTh were significantly different(P<0.05). TbN, TbPf, and SMI showed statistically significant differences between imaging methods(P<0.05). The consistency and absolute agreement between micro-CT and CBCT were excellent for all variables. Conclusion: This study demonstrated the potential of high-resolution CBCT imaging for quantitative bone morphometry assessment.

• 치과방사선
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• 제22권2호
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• pp.273-282
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• 1992

The purpose of this study was to propose the utility which was evaluated the digital image processing and clinical application of the videodensitomery. The experiments were performed with IBM-PC/16bit-AT compatible, video camera(CCdtr55, Sony Co., Japan), an color monitor(MultiSync 3D, NEC, Japan) providing the resolution of 512×480 and 64 levels of gray. Sylvia Image Capture Board for the ADC(analog to digital converter) was used, composed of digitized image from digital signal and the radiographic density was measured by 256 level of gray. The periapical radiograph(Ektaspeed EP-21, Kodak Co., U. S. A) which was radiographed dried human mandible by exposure condition of 70 kVp and 48 impulses, was used for primary X-ray detector. And them evaluated for digitzed image by low and high pass filtering, correlations between aluminum equivalent values and the thickness of aluminum step wedge, aluminum equivalent values of sound enamel, dentin, and alveolar bone, the range of diffuse density for gray level ranging from 0 to 255. The obtained results were as follows: 1. The edge between aluminum steps of digitized image were somewhat blurred by low pass filtering, but edge enhancement could be resulted by high pass filtering. Expecially, edge enhancement between distal root of lower left 2nd molar and alveolar lamina dura was observed. 2. The correlation between aluminum equivalent values and the thickness of aluminum step wedge was intimated, yielding the coefficient of correlation r=0.9997(p<0.00l), the regression line was described by Y=0.9699X+0.456, and coefficient of variation amounting to 1.5%. 3. The aluminum equivalent values of sound enamel, dentin, and alvolar bone were 15.41㎜, 12.48㎜, 10.35㎜, respectively. 4. The range of diffuse density for gray level ranging from 0 to 255 was wider enough than that of photodenstiometer to be within the range of 1-4.9.

• 대한치과교정학회지
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• 제30권6호
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• pp.723-730
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• 2000

교정적인 치아이동은 치주조직, 특히 치조골의 개조를 필요로 한다. 불소는 파골세포에 의한 골흡수를 방해하는 물질로 알려져 있다. 이 연구의 목적은 불소의 섭취가 교정적인 치아이동시 압박측 치주조직에서 파골세포의 출현에 어떠한 영향을 끼치는 지를 조사하는 것이다. 40마리의 백서에게 60일동안 불화나트륨(NaF)가 각각 0, 10, 25 mg/kg/일 함유된 물을 음수시킨 후, 약 50-70g의 교정력을 가하여 상악 제 1 대구치를 근심쪽으로 경사이동시켰다. 교정력을 가한 24, 48, 그리고 96 시간 후에 대조군과 실험군을 희생시킨 후 조직편을 제작하여 상악 제 1 대구치의 압박측 치주조직 $450\times700\;{\mu}m^2$을 관찰하여 출현한 파골세포의 수와 흡수량을 조사하여 다음과 같은 결론을 내렸다. 1. 모든 측정시간에서 25 mg/kg/일 군에서 대조군보다 파골세포의 수가 유의성 있게 적었다. (p<0.05) 2. 24, 48시간 측정에서 25 mg/kg/일 군에서 대조군보다 흡수되는 면적이 유의성 있게 적었다. (p<0.05) 3. 대조군에서는 48시간에서 96시간 사이에 흡수되는 면적이 약간 감소하였으나, 10 mg/kg/일 군과 25 mg/kg/일 군 모두에서는 약간 증가하였다.

• 대한치과교정학회지
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• 제35권4호
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• pp.262-274
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• 2005

본 연구는 치주인대 세포에 지속적이고 점진적 인장력을 가하여 치아 이동 시 형성되는 인장부위의 기계적 자극에 대한 생화학적 전달과 치조골 흡수와 생성 조절 기전을 이해하고자 하였다 치주인대 세포가 배양된 유연한 성장 표면을 가진 배지에 지속적이고 점진적인 인장력을 가하고 골흡수 인자인 $PGE_2$와 골형성 인자인 ALP의 생성량을 1 3 5. 12시간 후에 측정하여 정량비교하였고 파골세포 분화기전을 조절하는 OPG RANKL의 인자들과 matrix metalloproteinase(MMP)-1, -8, -9, -13, tissue inhibitor of matrix metalloproteinase(TIMP)-1의 인자들을 역전사 중합효소 연쇄반응 검사하여 m-RNA 발현을 비교한 결과 치주인대 세포에 인장력을 가한 경우 대조 군보다 $PGE_2$의 농도가 적었고 (p<0.05) ALP의 농도 변화는 없었으며 OPG의 mRNA 발현이 증가하였으나, RANKL의 mRNA 발현은 감소하였다 그리고 TIMP-1과 MMP-1 -8 -9, -13의 mRNA 발현이 대조군과 차이가 없었다. 이상의 연구에서 사람의 치주인대 세포는 점진적이고 지속적인 인장력에 대한 반응으로 $PGE_2$의 생성과 RANKL의 mRNA 발현은 감소하고 OPG의 mRNA 발현은 증가하여 골흡수를 억제하는 효과를 보이는 것으로 나타났다.

• 대한치과교정학회지
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• 제25권1호
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• pp.101-110
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• 1995

악교정수술을 요하는 악안면 기형환자에서 술후 교정치료시기는 골 치유정도 또는 골편의 안정성과 환자의 악골운동 정도에 따라 결정된다. 근래에 악교정 수술시 이동골편의 고정에 miniplate나 screw등을 이용한 견고성 고정 방법이 증가하는 추세이고 이는 술후 악간 고정기간을 최소화하고 교정력에 의한 골편의 변위 가능성을 줄이므로써 술후 조기에 교정치료를 가능하게 하였다. 한편 술후 조기에 교정치료를 시행할 경우는 골 절단술에 의한 혈류량의 변화와 외과적 처치에 의한 치주조직의 염증반응과 대사작용의 증가 등으로 인해 일반적인 치아이동과는 골개조, 초자양 변성 및 치근흡수 등에서 다소 차이를 보일 것으로 예상된다. 이에 저자 등은 고양이의 상악골 협측 치근단 하부에 수평적 골절단술을 시행한 후 즉시 교정력을 가하여 초기의 치주조직 반응을 교정력만을 가했을 때의 조직반응과 비교 관찰함으로써 다음과 같은 결과를 얻었다. 골절단술 시행후 즉시 교정력을 가한 실험군에서 교정력만을 가한 대조군에 비해 1. 압박측에서 치조골면을 따라 보이는 파골세포의 수가 증가하였고 골흡수 양상도 보다 직접성으로 관찰되었다. 2. 압박측에서 초자양 변성정도는 보다 경미하게 관찰되었다. 3. 견인측에서 신생골 형성은 치조골면을 따라 균일하게 형성되었고 대조군에 비해 다소 증가된 양상으로 뚜렷한 휴지선이 관찰되었다. 4. 치근흡수는 양군 모두에서 관찰되지 않았다.

• Imaging Science in Dentistry
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• 제41권3호
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• pp.115-121
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• 2011

Purpose : This article is to describe a modified device for intraoral radiography which was developed to obtain reproducible radiographic images for assessment of distal osseous defects of the mandibular second molar (2 Mm) after impacted third molar (3 Mm) surgery. Materials and Methods : A commercial available alignment system for posterior region was modified by adding a reference gauge pin (millimetric) and threading a hollow acrylic cylinder at the ring of the radiographic positioner to attach the X-ray collimator. The design included customized resin acrylic stent for the occlusal surface of the 2Mm in maximum intercuspal position, individualizing the biteblock positioner. Periapical radiographs were taken before and after surgical extraction of 3 Mm, employing the radiographic technique of parallelism described by Kugelberg (1986) with this modified film holder and inserting the gauge pin on the deepest bone probing depth point. Results : This technique permitted to obtain standardized periapical radiographs with a moderate to high resolution, repeatability, and accuracy. There was no difference between the measurements on the pre- and post-operative radiographs. This technique allowed better maintenance of the same geometric position compared with conventional one. The insertion of the gauge pin provided the same reference point and localized the deepest osseous defect on the two-dimensional radiographs. Conclusion : This technique allowed better reproducibility in posterior radiographic records (distal surface of 2 Mm) and more accurate measurements of radiographic bone level by the use of a millimetric pin.

• Imaging Science in Dentistry
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• 제47권3호
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• pp.199-207
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• 2017

Purpose: Evaluation of alveolar bone is important in the diagnosis of dental diseases. The periodontal ligament space is difficult to clearly depict in cone-beam computed tomography images because the reconstruction filter conditions during image processing cause image blurring, resulting in decreased spatial resolution. We examined different reconstruction filters to assess their ability to improve spatial resolution and allow for a clearer visualization of the periodontal ligament space. Materials and Methods: Cone-beam computed tomography projections of 2 skull phantoms were reconstructed using 6 reconstruction conditions and then compared using the Thurstone paired comparison method. Physical evaluations, including the modulation transfer function and the Wiener spectrum, as well as an assessment of space visibility, were undertaken using experimental phantoms. Results: Image reconstruction using a modified Shepp-Logan filter resulted in better sensory, physical, and quantitative evaluations. The reconstruction conditions substantially improved the spatial resolution and visualization of the periodontal ligament space. The difference in sensitivity was obtained by altering the reconstruction filter. Conclusion: Modifying the characteristics of a reconstruction filter can generate significant improvement in assessments of the periodontal ligament space. A high-frequency enhancement filter improves the visualization of thin structures and will be useful when accurate assessment of the periodontal ligament space is necessary.

• Journal of Periodontal and Implant Science
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• 제47권3호
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• pp.143-153
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• 2017

Purpose: The aim of the present exploratory study was to evaluate extraction socket healing at sites with a history of periodontal and endodontic pathology. Methods: The mandibular 4th premolar teeth in 5 adult beagle dogs served as experimental units. Periodontal and endodontic lesions were induced in 1 premolar site in each animal using wire ligatures and pulpal exposure over 3 months (diseased sites). The contralateral premolar sites served as healthy controls. The mandibular 4th premolar teeth were then extracted with minimal trauma, followed by careful wound debridement. The animals were sacrificed at days 1, 7, 30, 60, and 90 post-extraction for analysis, and the healing patterns at the healthy and diseased extraction sites were compared using radiography, scanning electron microscopy, histology, and histometry. Results: During the first 7 days of healing, a significant presence of inflammatory granulation tissue was noted at the diseased sites (day 1), along with a slightly accelerated rate of fibrin clot resolution on day 7. On day 30, the diseased extraction sites showed a greater percentage of persistent fibrous connective tissue, and an absence of bone marrow formation. In contrast, healthy sites showed initial signs of bone marrow formation on day 30, and subsequently a significantly greater proportion of mature bone marrow formation on both days 60 and 90. Radiographs exhibited sclerotic changes adjoining apical endodontic lesions, with scanning electron microscopy showing collapsed Volkmann canals protruding from these regions in the diseased sites. Furthermore, periodontal ligament fibers exhibited a parallel orientation to the alveolar walls of the diseased sites, in contrast to a perpendicular arrangement in the healthy sites. Conclusions: Within the limitations of this study, it appears that a history of periodontal and endodontic pathology may critically affect bone formation and maturation, leading to delayed and compromised extraction socket healing.