• 제목/요약/키워드: Oral and Maxillofacial

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Mineral trioxide aggregate, calcium sulfate와 calcium hydroxide의 치수에 대한 반응 (Pulp Response of Mineral Trioxide Aggregate, Calcium Sulfate or Calcium Hydroxide)

  • 윤영란;양인석;황윤찬;황인남;최홍란;윤숙자;김선헌;오원만
    • Restorative Dentistry and Endodontics
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    • 제32권2호
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    • pp.95-101
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    • 2007
  • 개의 치수에 MTA, calcium hydroxide 및 calcium sulfate로 치수복조 후 치수 반응을 서로 비교하여 MTA와 calcium sulfate가 임상적으로 치수복조제로서 사용 가능할 것인가를 구명하고자 본 연구를 시행하였다. 8개월 된 2마리 개의 24개의 치아가 본 연구에 사용되었다 전신 마취하에 고속 핸드피스를 사용하여 멸균된 #2 round bur로 치경부에 와동을 형성한 후 치수를 노출시켰다. MTA, calcium hydroxide 및 calcium sulfate를 치수노출부에 도포하였다. 와동 부위는 IRM으로 가봉하고 광중합레진으로 수복하였다. 처리 2개월 후, 전신 마취하에 희생시킨 후 조직학적으로 관찰하였다. MTA처리군에서는 치수 노출부위에 경조직의 상아질교가 형성되었으며 새로 형성된 상아질교 하방에 조상아세포가 새로 형성되었다. 치수충혈과 함께 국소적 인 혈관 증식 이 나타났으며 치수에 염증반응은 나타나지 않았다. Calcium hydroxide로 처리한 군은 상아질교 하방에 조상아세포가 관찰되지 않았으며 만성 염증반응이 다양하게 나타났다. Calcium sulfate로 처리한 군은 경조직의 상아질교가 관찰되었으며, 상아질교 하방에 조상아세포 층이 새로 관찰되었다. 몇몇의 중성구 침윤과 함께 미약한 정도의 만성염증반응이 관찰되었다. 이상의 결과에서 MTA가 calcium hydroxide및 calcium sulfate에 비해 치수에 생체친화적임을 시사하며 기계적 치수노출시 치수복조제로 사용할 수 있음을 시사한다.

Accuracy of three-dimensional periodontal ligament models generated using cone-beam computed tomography at different resolutions for the assessment of periodontal bone loss

  • Hangmiao Lyu;Li Xu;Huimin Ma;Jianxia Hou;Xiaoxia Wang;Yong Wang;Yijiao Zhao;Weiran Li;Xiaotong Li
    • 대한치과교정학회지
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    • 제53권2호
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    • pp.77-88
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    • 2023
  • Objective: To develop a method for generating three-dimensional (3D) digital models of the periodontal ligament (PDL) using 3D cone-beam computed tomography (CBCT) reconstruction and to evaluate the accuracy and agreement of the 3D PDL models in the measurement of periodontal bone loss. Methods: CBCT data collected from four patients with skeletal Class III malocclusion prior to periodontal surgery were reconstructed at three voxel sizes (0.2 mm, 0.25 mm, and 0.3 mm), and 3D tooth and alveolar bone models were generated to obtain digital PDL models for the maxillary and mandibular anterior teeth. Linear measurements of the alveolar bone crest obtained during periodontal surgery were compared with the digital measurements for assessment of the accuracy of the digital models. The agreement and reliability of the digital PDL models were analyzed using intra- and interexaminer correlation coefficients and Bland-Altman plots. Results: Digital models of the maxillary and mandibular anterior teeth, PDL, and alveolar bone of the four patients were successfully established. Relative to the intraoperative measurements, linear measurements obtained from the 3D digital models were accurate, and there were no significant differences among different voxel sizes at different sites. High diagnostic coincidence rates were found for the maxillary anterior teeth. The digital models showed high intra- and interexaminer agreement. Conclusions: Digital PDL models generated by 3D CBCT reconstruction can provide accurate and useful information regarding the alveolar crest morphology and facilitate reproducible measurements. This could assist clinicians in the evaluation of periodontal prognosis and establishment of an appropriate orthodontic treatment plan.

CBCT-based assessment of root canal treatment using micro-CT reference images

  • Lamira, Alessando;Mazzi-Chaves, Jardel Francisco;Nicolielo, Laura Ferreira Pinheiro;Leoni, Graziela Bianchi;Silva-Sousa, Alice Correa;Silva-Sousa, Yara Terezinha Correa;Pauwels, Ruben;Buls, Nico;Jacobs, Reinhilde;Sousa-Neto, Manoel Damiao
    • Imaging Science in Dentistry
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    • 제52권3호
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    • pp.245-258
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    • 2022
  • Purpose: This study compared the root canal anatomy between cone-beam computed tomography (CBCT) and micro-computed tomography (micro-CT) images before and after biomechanical preparation and root canal filling. Materials and Methods: Isthmus-containing mesial roots of mandibular molars(n=14) were scanned by micro-CT and 3 CBCT devices: 3D Accuitomo 170 (ACC), NewTom 5G (N5G) and NewTom VGi evo (NEVO). Two calibrated observers evaluated the images for 2-dimensional quantitative parameters, the presence of debris or root perforation, and filling quality in the root canal and isthmus. The kappa coefficient, analysis of variance, and the Tukey test were used for statistical analyses(α=5%). Results: Substantial intra-observer agreement (κ=0.63) was found between micro-CT and ACC, N5G, and NEVO. Debris detection was difficult using ACC (42.9%), N5G (40.0%), and NEVO (40%), with no agreement between micro-CT and ACC, N5G, and NEVO (0.05<κ<0.12). After biomechanical preparation, 2.4%-4.8% of CBCT images showed root perforation that was absent on micro-CT. The 2D parameters showed satisfactory reproducibility between micro-CT and ACC, N5G, and NEVO (intraclass correlation coefficient: 0.60-0.73). Partially filled isthmuses were observed in 2.9% of the ACC images, 8.8% of the N5G and NEVO images, and 26.5% of the micro-CT images, with no agreement between micro-CT and ACC, and poor agreement between micro-CT and N5G and NEVO. Excellent agreement was found for area, perimeter, and the major and minor diameters, while the roundness measures were satisfactory. Conclusion: CBCT images aided in isthmus detection and classification, but did not allow their classification after biomechanical preparation and root canal filling.

Accuracy and reliability of 2-dimensional photography versus 3-dimensional soft tissue imaging

  • Ayaz, Irem;Shaheen, Eman;Aly, Medhat;Shujaat, Sohaib;Gallo, Giulia;Coucke, Wim;Politis, Constantinus;Jacobs, Reinhilde
    • Imaging Science in Dentistry
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    • 제50권1호
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    • pp.15-22
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    • 2020
  • Purpose: This study was conducted to objectively and subjectively compare the accuracy and reliability of 2-dimensional(2D) photography and 3-dimensional(3D) soft tissue imaging. Materials and Methods: Facial images of 50 volunteers(25 males, 25 females) were captured with a Nikon D800 2D camera (Nikon Corporation, Tokyo, Japan), 3D stereophotogrammetry (SPG), and laser scanning (LS). All subjects were imaged in a relaxed, closed-mouth position with a normal smile. The 2D images were then exported to Mirror® Software (Canfield Scientific, Inc, NJ, USA) and the 3D images into Proplan CMF® software (version 2.1, Materialise HQ, Leuven, Belgium) for further evaluation. For an objective evaluation, 2 observers identified soft tissue landmarks and performed linear measurements on subjects' faces (direct measurements) and both linear and angular measurements on all images(indirect measurements). For a qualitative analysis, 10 dental observers and an expert in facial imaging (subjective gold standard) completed a questionnaire regarding facial characteristics. The reliability of the quantitative data was evaluated using intraclass correlation coefficients, whereas the Fleiss kappa was calculated for qualitative data. Results: Linear and angular measurements carried out on 2D and 3D images showed excellent inter-observer and intra-observer reliability. The 2D photographs displayed the highest combined total error for linear measurements. SPG performed better than LS, with borderline significance (P=0.052). The qualitative assessment showed no significant differences among the 2D and 3D imaging modalities. Conclusion: SPG was found to a reliable and accurate tool for the morphological evaluation of soft tissue in comparison to 2D imaging and laser scanning.

코로나 바이러스 대유행에 따른 치과 의료 관리 가이드라인 (Guidelines for dental clinic infection prevention during COVID-19 pandemic)

  • 김진
    • 대한치과의료관리학회지
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    • 제8권1호
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    • pp.1-7
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    • 2020
  • Dental settings have unique characteristics that warrant specific infection control considerations, including (1) prioritizing the most critical dental services and provide care in a way that minimizes harm to patients due to delayed care, or harm to personnel from potential exposure to persons infected with the COVID-19 disease, and (2) proactively communicate to both personnel and patients the need for them to stay at home if sick. For health care, an interim infection prevention and control recommendation (COVID-19) is recommended for patients suspected of having coronavirus or those whose status has been confirmed. SARS-CoV-2, which is the virus that causes COVID-19, is thought to be spread primarily between people who are in close contact with one another (within 6 feet) through respiratory droplets that are produced when an infected person coughs, sneezes, or talks. Airborne transmission from person-to-person over long distances is unlikely. However, COVID-19 is a new disease, and there remain uncertainties about its mode of spreads and the severity of illness it causes. The virus has been shown to persist in aerosols for several hours, and on some surfaces for days under laboratory conditions. COVID-19 may also be spread by people who are asymptomatic. The practice of dentistry involves the use of rotary dental and surgical instruments, such as handpieces or ultrasonic scalers, and air-water syringes. These instruments create a visible spray that can contain particle droplets of water, saliva, blood, microorganisms, and other debris. While KF 94 masks protect the mucous membranes of the mouth and nose from droplet spatter, they do not provide complete protection against the inhalation of airborne infectious agents. If the patient is afebrile (temperature <100.4°F)* and otherwise without symptoms consistent with COVID-19, then dental care may be provided using appropriate engineering and administrative controls, work practices, and infection control considerations. It is necessary to provide supplies for respiratory hygiene and cough etiquette, including alcohol-based hand rub (ABHR) with 60%~95% alcohol, tissues, and no-touch receptacles for disposal, at healthcare facility entrances, waiting rooms, and patient check-ins. There is also the need to install physical barriers (e.g., glass or plastic windows) in reception areas to limit close contact between triage personnel and potentially infectious patients. Ideally, dental treatment should be provided in individual rooms whenever possible, with a spacing of at least 6 feet between the patient chairs. Further, the use of easy-to-clean floor-to-ceiling barriers will enhance the effectiveness of portable HEPA air filtration systems. Before and after all patient contact, contact with potentially infectious material, and before putting on and after removing personal protective equipment, including gloves, hand hygiene after removal is particularly important to remove any pathogens that may have been transferred to the bare hands during the removal process. ABHR with 60~95% alcohol is to be used, or hands should be washed with soap and water for at least 20 s.

부분 무치악 환자에서 마그네슘 이온주입 임플란트의 성공률에 대한 전향적 임상연구 (The success rate of Mg-incorporated oxidized implants in partially edentulous patients: a prospective clinical study)

  • 최수정;유정호;이규복;김진욱
    • 대한치과보철학회지
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    • 제50권3호
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    • pp.176-183
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    • 2012
  • 연구 목적: 부분 무치악 환자에서 Mg titanate implant (M Implant system, Shinhung, Korea)의보철 후 1년간의 방사선사진을 이용한 변연골 흡수량과 Osstell$^{(R)}$을 이용한 임플란트 안정성 평가 결과를 분석하여 임상적인 성공률에 대해 알아보고자 한다. 연구 재료 및 방법: 38명의 환자에 79개의 임플란트를 식립하여 보철 후 1년 동안 변연골 흡수량, 임플란트의 동요도, 임플란트 식립 위치에 따른 분포 및 성공률, 보철 전후에 따른 성공률을 분석했다. 결과: 변연골의 흡수량은 보철물 장착 후 1년간의 평가에서 상악에서는 평균 1.537 mm, 하악에서는 평균 1.172 mm의 변연골 흡수가 관찰되었으며, 전체적인 상하악의 평균 변연골 흡수량은 1.255 mm로 관찰되었다. 수술 후 시간이 경과함에 따라 ISQ값은 미약하게 감소하였다가 증가하는 경향을 보였으나, 상악과 하악 모두에서 식립 당일 이후 예비 인상일, 최종 보철물의 장착일과 주기적인 평가 기간 동안 ISQ값의 큰 증가나 감소를 나타내지는 않았다. 성공률은 상악에서의 94.12%였고, 하악에서의 98.39%였다. 결론: 본 실험의 결과로 미루어 Mg titanate implant는 임상적으로 양호한 결과를 보여주었다.

Gene signature for prediction of radiosensitivity in human papillomavirus-negative head and neck squamous cell carcinoma

  • Kim, Su Il;Kang, Jeong Wook;Noh, Joo Kyung;Jung, Hae Rim;Lee, Young Chan;Lee, Jung Woo;Kong, Moonkyoo;Eun, Young-Gyu
    • Radiation Oncology Journal
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    • 제38권2호
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    • pp.99-108
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    • 2020
  • Purpose: The probability of recurrence of cancer after adjuvant or definitive radiotherapy in patients with human papillomavirus-negative (HPV(-)) head and neck squamous cell carcinoma (HNSCC) varies for each patient. This study aimed to identify and validate radiation sensitivity signature (RSS) of patients with HPV(-) HNSCC to predict the recurrence of cancer after radiotherapy. Materials and Methods: Clonogenic survival assays were performed to assess radiosensitivity in 14 HNSCC cell lines. We identified genes closely correlated with radiosensitivity and validated them in The Cancer Genome Atlas (TCGA) cohort. The validated RSS were analyzed by ingenuity pathway analysis (IPA) to identify canonical pathways, upstream regulators, diseases and functions, and gene networks related to radiosensitive genes in HPV(-) HNSCC. Results: The survival fraction of 14 HNSCC cell lines after exposure to 2 Gy of radiation ranged from 48% to 72%. Six genes were positively correlated and 35 genes were negatively correlated with radioresistance, respectively. RSS was validated in the HPV(-) TCGA HNSCC cohort (n = 203), and recurrence-free survival (RFS) rate was found to be significantly lower in the radioresistant group than in the radiosensitive group (p = 0.035). Cell death and survival, cell-to-cell signaling, and cellular movement were significantly enriched in RSS, and RSSs were highly correlated with each other. Conclusion: We derived a HPV(-) HNSCC-specific RSS and validated it in an independent cohort. The outcome of adjuvant or definitive radiotherapy in HPV(-) patients with HNSCC can be predicted by analyzing their RSS, which might help in establishing a personalized therapeutic plan.

LINE-1 and Alu Methylation Patterns in Lymph Node Metastases of Head and Neck Cancers

  • Kitkumthorn, Nakarin;Keelawat, Somboon;Rattanatanyong, Prakasit;Mutirangura, Apiwat
    • Asian Pacific Journal of Cancer Prevention
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    • 제13권9호
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    • pp.4469-4475
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    • 2012
  • Background: The potential use of hypomethylation of Long INterspersed Element 1 (LINE-1) and Alu elements (Alu) as a biomarker has been comprehensively assessed in several cancers, including head and neck squamous cell carcinoma (HNSCC). Failure to detect occult metastatic head and neck tumors on radical neck lymph node dissection can affect the therapeutic measures taken. Objective: The aim of this study was to investigate the LINE-1 and Alu methylation status and determine whether it can be applied for detection of occult metastatic tumors in HNSCC cases. Methods: We used the Combine Bisulfite Restriction Analysis (COBRA) technique to analyse LINE-1 and Alu methylation status. In addition to the methylation level, LINE-1 and Alu loci were classified based on the methylation statuses of two CpG dinucleotides in each allele as follows: hypermethylation ($^mC^mC$), hypomethylation ($^uC^uC$), and 2 forms of partial methylation ($^mC^uC$ and $^uC^mC$). Sixty-one lymph nodes were divided into 3 groups: 1) non-metastatic head and neck cancer (NM), 2) histologically negative for tumor cells of cases with metastatic head and neck cancer (LN), and 3) histologically positive for tumor cells (LP). Results: Alu methylation change was not significant. However, LINE-1 methylation of both LN and LP was altered, as demonstrated by the lower LINE-1 methylation levels (p<0.001), higher percentage of $^mC^uC$ (p<0.01), lower percentage of $^uC^mC$ (p<0.001) and higher percentage of $^uC^uC$ (p<0.001). Using receiver operating characteristic (ROC) curve analysis, $%^uC^mC$ and $%^mC^uC$ values revealed a high level of AUC at 0.806 and 0.716, respectively, in distinguishing LN from NM. Conclusion: The LINE-1 methylation changes in LN have the same pattern as that in LP. This epigenomic change may be due to the presence of occult metastatic tumor in LN cases.

Analyses Using Micro-CT Scans and Tissue Staining on New Bone Formation and Bone Fusion According to the Timing of Cranioplasty via Frozen Autologous Bone Flaps in Rabbits : A Preliminary Report

  • Shin, Hee Sup;Lee, Deok-Won;Lee, Seung Hwan;Koh, Jun Seok
    • Journal of Korean Neurosurgical Society
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    • 제57권4호
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    • pp.242-249
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    • 2015
  • Objective : The timing of cranioplasty and method of bone flap storage are known risk factors of non-union and resorption of bone flaps. In this animal experimental study, we evaluated the efficacy of cranioplasty using frozen autologous bone flap, and examined whether the timing of cranioplasty after craniectomy affects bone fusion and new bone formation. Methods : Total 8 rabbits (male, older than 16 weeks) were divided into two groups of early cranioplasty group (EG, 4 rabbits) and delayed cranioplasty group (DG, 4 rabbits). The rabbits of each group were performed cranioplasty via frozen autologous bone flaps 4 weeks (EG) and 8 weeks (DG) after craniectomy. In order to obtain control data, the cranioplasty immediate after craniectomy were made on the contralateral cranial bone of the rabbits (control group, CG). The bone fusion and new bone formation were evaluated by micro-CT scan and histological examination 8 weeks after cranioplasty on both groups. Results : In the micro-CT scans, the mean values of the volume and the surface of new bone were $50.13{\pm}7.18mm^3$ and $706.23{\pm}77.26mm^2$ in EG, $53.78{\pm}10.86mm^3$ and $726.60{\pm}170.99mm^2$ in DG, and $31.51{\pm}12.84mm^3$ and $436.65{\pm}132.24mm^2$ in CG. In the statistical results, significant differences were shown between EG and CG and between DG and CG (volume : p=0.028 and surface : p=0.008). The histological results confirmed new bone formation in all rabbits. Conclusion : We observed new bone formation on all the frozen autologous bone flaps that was stored within 8 weeks. The timing of cranioplasty may showed no difference of degree of new bone formation. Not only the healing period after cranioplasty but the time interval from craniectomy to cranioplasty could affect the new bone formation.

Periodontal inflamed surface area as a novel numerical variable describing periodontal conditions

  • Park, Shin-Young;Ahn, Soyeon;Lee, Jung-Tae;Yun, Pil-Young;Lee, Yun Jong;Lee, Joo Youn;Song, Yeong Wook;Chang, Yoon-Seok;Lee, Hyo-Jung
    • Journal of Periodontal and Implant Science
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    • 제47권5호
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    • pp.328-338
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    • 2017
  • Purpose: Chronic periodontitis is an inflammatory disease induced by pathogenic bacterial accumulation. A novel index, the periodontal inflamed surface area (PISA), represents the sum of the periodontal pocket depth of bleeding on probing (BOP)-positive sites. It is advantageous for data processing and analysis because it can be treated as a continuous variable to quantify periodontal inflammation. In the present study, we evaluated correlations between PISA and periodontal classifications, and examined PISA as an index integrating the discrete conventional periodontal indexes. Methods: This study was a cross-sectional subgroup analysis of data from a prospective cohort study investigating the association between chronic periodontitis and the clinical features of ankylosing spondylitis. Data from 84 patients without systemic diseases (the control group in the previous study) were analyzed in the present study. Results: PISA values were positively correlated with conventional periodontal classifications (Spearman correlation coefficient=0.52; P<0.01) and with periodontal indexes, such as BOP and the plaque index (PI) (r=0.94; P<0.01 and r=0.60; P<0.01, respectively; Pearson correlation test). Porphyromonas gingivalis expression and the presence of serum P. gingivalis antibodies were significant factors affecting PISA values in a simple linear regression analysis, together with periodontal classification, PI, bleeding index, and smoking, but not in the multivariate analysis. In the multivariate linear regression analysis, PISA values were positively correlated with the quantity of current smoking, PI, and severity of periodontal disease. Conclusions: PISA integrates multiple periodontal indexes, such as probing pocket depth, BOP, and PI into a numerical variable. PISA is advantageous for quantifying periodontal inflammation and plaque accumulation.