• 제목/요약/키워드: Cone Beam Computed Tomography(CBCT)

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Endodontic management of a mandibular second molar with radix entomolaris: a case report

  • Hannah, Rosaline;Kandaswamy, Deivanayagam;Jayaprakash, Nachimuthu
    • Restorative Dentistry and Endodontics
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    • 제39권2호
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    • pp.132-136
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    • 2014
  • The presence of radix entomolaris (RE) in a mandibular first molar is a common occurrence in certain ethnic groups, but the presence of RE in a mandibular second molar is a rare occurrence. In the present case, RE was identified from preoperative radiographs and confirmed using cone-beam computed tomography (CBCT). The access cavity was modified to locate the RE. Cleaning and shaping were performed with nickel-titanium rotary instruments. Obturation was completed with gutta-percha cones using AH Plus (Dentsply Detrey GmbH) as sealer. From the CBCT axial images, the RE was determined to have a Type III curvature by the De Moor classification, Type B separate RE by the Carlsen and Alexandersen classification, and radiographically, a Type i image by the Wang classification. The presence of RE in the mandibular second molar makes it essential to anticipate and treat the distolingual root canal. This case report highlights the usefulness of CBCT for assessing RE in the mandibular second molar, which can help the clinician in making a confirmatory diagnosis and assessing the morphology of the root canal.

Investigation of the effects of storage time on the dimensional accuracy of impression materials using cone beam computed tomography

  • Alkurt, Murat;Duymus, Zeynep Yesil;Dedeoglu, Numan
    • The Journal of Advanced Prosthodontics
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    • 제8권5호
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    • pp.380-387
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    • 2016
  • PURPOSE. The storage conditions of impressions affect the dimensional accuracy of the impression materials. The aim of the study was to assess the effects of storage time on dimensional accuracy of five different impression materials by cone beam computed tomography (CBCT). MATERIALS AND METHODS. Polyether (Impregum), hydrocolloid (Hydrogum and Alginoplast), and silicone (Zetaflow and Honigum) impression materials were used for impressions taken from an acrylic master model. The impressions were poured and subjected to four different storage times: immediate use, and 1, 3, and 5 days of storage. Line 1 (between right and left first molar mesiobuccal cusp tips) and Line 2 (between right and left canine tips) were measured on a CBCT scanned model, and time dependent mean differences were analyzed by two-way univariate and Duncan's test (${\alpha}=.05$). RESULTS. For Line 1, the total mean difference of Impregum and Hydrogum were statistically different from Alginoplast (P<.05), while Zetaflow and Honigum had smaller discrepancies. Alginoplast resulted in more difference than the other impressions (P<.05). For Line 2, the total mean difference of Impregum was statistically different from the other impressions. Significant differences were observed in Line 1 and Line 2 for the different storage periods (P<.05). CONCLUSION. The dimensional accuracy of impression material is clinically acceptable if the impression material is stored in suitable conditions.

Condylar bony changes in patients with temporomandibular disorders: a CBCT study

  • Nah, Kyung-Soo
    • Imaging Science in Dentistry
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    • 제42권4호
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    • pp.249-253
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    • 2012
  • Purpose: Diagnosis of osteoarthritis most commonly depends on clinical and radiographic findings. The present study attempted to observe the bony changes in temporomandibular joint (TMJ) patients from all age groups. Materials and Methods: The first-visit clinical records and cone beam computed tomography (CBCT) data of 440 TMJs from 220 consecutive TMJ patients were reviewed retrospectively. Results: The most frequent condylar bony change observed was sclerosis (133 joints, 30.2%) followed by surface erosion (129 joints, 29.3%), flattening of the articular surface (112 joints, 25.5%), and deviation in form (58 joints, 13.2%), which included 33 TMJs in a cane-shape, 16 with a lateral or medial pole depression, 6 with posterior condylar surface flattening, and 3 with a bifid-shaped condyle. Fifty-three joints (12.0%) showed hypoplastic condyles but only 1 joint showed hyperplasia. Osteophyte was found in 35 joints (8.0%) and subcortical cyst in 24 joints (5.5%), 5 of which had surface erosion as well. One hundred nineteen joints (27.0%) had only one kind of condylar bony change, 66 joints (15.0%) had two, 52 joints (11.8%) had three, 12 joints (5.0%) had four, and 6 joints (1.4%) had five kinds of condylar bony changes at the same time. Eighty-five (65.9%) of 129 joints with surface erosion had pain recorded at the chief complaint. Conclusion: With more widespread use of CBCT, more specific or detailed guidelines for osteoarthritis are needed.

Three-dimensional comparison of 2 digital models obtained from cone-beam computed tomographic scans of polyvinyl siloxane impressions and plaster models

  • Park, Jin-Yi;Kim, Dasomi;Han, Sang-Sun;Yu, Hyung-Seog;Cha, Jung-Yul
    • Imaging Science in Dentistry
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    • 제49권4호
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    • pp.257-263
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    • 2019
  • Purpose: This study was performed to evaluate the dimensional accuracy of digital dental models constructed from cone-beam computed tomographic (CBCT) scans of polyvinyl siloxane (PVS) impressions and cast scan models. Materials and Methods: A pair of PVS impressions was obtained from 20 subjects and scanned using CBCT (resolution, 0.1 mm). A cast scan model was constructed by scanning the gypsum model using a model scanner. After reconstruction of the digital models, the mesio-distal width of each tooth, inter-canine width, and inter-molar width were measured, and the Bolton ratios were calculated and compared. The 2 models were superimposed and the difference between the models was measured using 3-dimensional analysis. Results: The range of mean error between the cast scan model and the CBCT scan model was -0.15 mm to 0.13 mm in the mesio-distal width of the teeth and 0.03 mm to 0.42 mm in the width analysis. The differences in the Bolton ratios between the cast scan models and CBCT scan models were 0.87 (anterior ratio) and 0.72 (overall ratio), with no significant difference (P>0.05). The mean maxillary and mandibular difference when the cast scan model and the CBCT scan model were superimposed was 53 ㎛. Conclusion: There was no statistically significant difference in most of the measurements. The maximum tooth size difference was 0.15mm, and the average difference in model overlap was 53 ㎛. Digital models produced by scanning impressions at a high resolution using CBCT can be used in clinical practice.

Analysis of C-shaped root canal configuration in maxillary molars in a Korean population using cone-beam computed tomography

  • Jo, Hyoung-Hoon;Min, Jeong-Bum;Hwang, Ho-Keel
    • Restorative Dentistry and Endodontics
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    • 제41권1호
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    • pp.55-62
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    • 2016
  • Objectives: The purpose of this study was to investigate the incidence of root fusion and C-shaped root canals in maxillary molars, and to classify the types of C-shaped canal by analyzing cone-beam computed tomography (CBCT) in a Korean population. Materials and Methods: Digitized CBCT images from 911 subjects were obtained in Chosun University Dental Hospital between February 2010 and July 2012 for orthodontic treatment. Among them, a total of selected 3,553 data of maxillary molars were analyzed retrospectively. Tomography sections in the axial, coronal, and sagittal planes were displayed by PiViewstar and Rapidia MPR software (Infinitt Co.). The incidence and types of root fusion and C-shaped root canals were evaluated and the incidence between the first and the second molar was compared using Chi-square test. Results: Root fusion was present in 3.2% of the first molars and 19.5% of the second molars, and fusion of mesiobuccal and palatal root was dominant. C-shaped root canals were present in 0.8% of the first molars and 2.7% of the second molars. The frequency of root fusion and C-shaped canal was significantly higher in the second molar than the first molar (p < 0.001). Conclusions: In a Korean population, maxillary molars showed total 11.3% of root fusion and 1.8% of C-shaped root canals. Furthermore, root fusion and C-shaped root canals were seen more frequently in the maxillary second molars.

Accuracy of Bolton analysis measured in laser scanned digital models compared with plaster models (gold standard) and cone-beam computer tomography images

  • Kim, Jooseong;Lagravere, Manuel O.
    • 대한치과교정학회지
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    • 제46권1호
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    • pp.13-19
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    • 2016
  • Objective: The aim of this study was to compare the accuracy of Bolton analysis obtained from digital models scanned with the Ortho Insight three-dimensional (3D) laser scanner system to those obtained from cone-beam computed tomography (CBCT) images and traditional plaster models. Methods: CBCT scans and plaster models were obtained from 50 patients. Plaster models were scanned using the Ortho Insight 3D laser scanner; Bolton ratios were calculated with its software. CBCT scans were imported and analyzed using AVIZO software. Plaster models were measured with a digital caliper. Data were analyzed with descriptive statistics and the intraclass correlation coefficient (ICC). Results: Anterior and overall Bolton ratios obtained by the three different modalities exhibited excellent agreement (> 0.970). The mean differences between the scanned digital models and physical models and between the CBCT images and scanned digital models for overall Bolton ratios were $0.41{\pm}0.305%$ and $0.45{\pm}0.456%$, respectively; for anterior Bolton ratios, $0.59{\pm}0.520%$ and $1.01{\pm}0.780%$, respectively. ICC results showed that intraexaminer error reliability was generally excellent (> 0.858 for all three diagnostic modalities), with < 1.45% discrepancy in the Bolton analysis. Conclusions: Laser scanned digital models are highly accurate compared to physical models and CBCT scans for assessing the spatial relationships of dental arches for orthodontic diagnosis.

Cone beam CT를 이용한 안면골격형태에 따른 상기도 공간 분석 (Pharyngeal airway analysis of different craniofacial morphology using cone-beam computed tomography (CBCT))

  • 김용일;김성식;손우성;박수병
    • 대한치과교정학회지
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    • 제39권3호
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    • pp.136-145
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    • 2009
  • 상기도 공간은 3차원 입체 구조물로서 두부규격방사선사진 등으로 분석하기에는 평가의 한계가 존재하였다. 본 연구는 최근 방사선 피폭량 등의 감소로 그 활용도가 높아진 cone beam CT (CBCT)를 이용하여 안면골격형태에 따른 상기도 공간의 면적, 전후방 폭경 및 측방 폭경을 측정하고 그 관련성을 알아보았다. 102명을 대상으로 CBCT (VCT, Vatech, Seoul, Korea)를 촬영하였으며, FH plane에 평행하면서 aa point (the most anterior point on the anterior arch of atlas), $CV_{2ia}$, $CV_{3ia}$ point (most infero-anterior point on the body of the second & third cervical vertebra)를 지나는 평면을 기준으로 설정하였다. 각 항목의 계측치는 one-way ANOVA를 이용하여 통계처리하고 Duncan test로 사후검정하였다. 연구 결과, 안면 골격형태에 따른 측방 폭경에는 유의한 차이가 없었다. Group 2 (Class II) 집단은 aa plane, $CV_2$ plane, $CV_3$ plane에 의해 형성된 상기도 공간의 단면적이 좁았으며, 전후방 폭경도 Group 3 (Class III)에 비해 유의성 있게 좁았다. 수직 안면골격형태와 정상 안면골격 형태간의 유의성 있는 차이는 없었으나, aa plane에서 형성된 상기도 공간의 전후방 폭경은 Group 1V (Class I vertical)가 Group 1N (Class I normal)에 비해 유의성 있게 좁은 것으로 나타났다 (p < 0.05).

Cone-beam CT를 이용한 제II급 부정교합 아동의 상기도 형태에 관한 3차원적 연구 (Three dimensional analysis of the upper airway and facial morphology in children with Class II malocclusion using cone-beam computed tomography)

  • 홍지숙;김대성;오경민;김윤지;이규홍;박양호
    • 대한치과교정학회지
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    • 제40권3호
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    • pp.134-144
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    • 2010
  • 성장기 아동의 상기도 협착은 두개안면 성장에 영향을 미칠 수 있다. 본 연구는 3차원 cone-beam computed tomography (CBCT)를 이용하여 제II급 부정교합 아동의 상기도 부피 및 단면적 계측치와 측모두부계측치를 비교하여 상기도와 안면 형태와의 연관성을 알아보고자 하였다. 37명의 아동(남자 17명, 여자 20명, 평균 연령 11.02세)의 CBCT를 촬영하였다. 연구 결과, 상기도의 PNS-posterior plane에서의 단면적($S_{PP}$)은 제II급 부정교합군에서 유의하게 작았다 (p < 0.05). 상기도 부피 계측치는 제II급 부정교합군에서 제I급 부정교합군보다 작았으나, 두 군 간 통계적으로 유의한 차이는 없었다. 제II급 부정교합군은 후안모고경(PFH), mandibular body length (p < 0.05), Pog to Nperp (p < 0.01)에서 제I급 부정교합군보다 유의하게 작은 값을 보였고, FMA (p < 0.05), ANB, facial convexity (p < 0.01)는 유의하게 큰 값을 보였다. 제II급 부정교합군의 PNS 전방의 상기도 부피($W_N$)는 ANB difference 각도와 음의 상관관계를 보였다 (p < 0.05). 제II급 부정교합 아동은 상대적으로 좁은 상기도 부피를 가지며 이에 따른 감소 된 후안모고경(PFH)과 하악골의 divergent한 안면 성장 양상을 보였다.

EFFECTIVE DOSE MEASUREMENT FOR CONE BEAM COMPUTED TOMOGRAPHY USING GLASS DOSIMETER

  • Moon, Young Min;Kim, Hyo-Jin;Kwak, Dong Won;Kang, Yeong-Rok;Lee, Man Woo;Ro, Tae-Ik;Kim, Jeung Kee;Jeong, Dong Hyeok
    • Nuclear Engineering and Technology
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    • 제46권2호
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    • pp.255-262
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    • 2014
  • During image-guided radiation therapy, the patient is exposed to unwanted radiation from imaging devices built into the medical LINAC. In the present study, the effective dose delivered to a patient from a cone beam computed tomography (CBCT) machine was measured. Absorbed doses in specific organs listed in ICRP Publication 103 were measured with glass dosimeters calibrated with kilovolt (kV) X-rays using a whole body physical phantom for typical radiotherapy sites, including the head and neck, chest, and pelvis. The effective dose per scan for the head and neck, chest, and pelvis were $3.37{\pm}0.29$, $7.36{\pm}0.33$, and $4.09{\pm}0.29$ mSv, respectively. The results highlight the importance of the compensation of treatment dose by managing imaging dose.

Head motion during cone-beam computed tomography: Analysis of frequency and influence on image quality

  • Moratin, Julius;Berger, Moritz;Ruckschloss, Thomas;Metzger, Karl;Berger, Hannah;Gottsauner, Maximilian;Engel, Michael;Hoffmann, Jurgen;Freudlsperger, Christian;Ristow, Oliver
    • Imaging Science in Dentistry
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    • 제50권3호
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    • pp.227-236
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    • 2020
  • Purpose: Image artifacts caused by patient motion cause problems in cone-beam computed tomography (CBCT) because they lead to distortion of the 3-dimensional reconstruction. This prospective study was performed to quantify patient movement during CBCT acquisition and its influence on image quality. Materials and Methods: In total, 412 patients receiving CBCT imaging were equipped with a wireless head sensor system that detected inertial, gyroscopic, and magnetometric movements with 6 dimensions of freedom. The type and amplitude of movements during CBCT acquisition were evaluated and image quality was rated in 7 different anatomical regions of interest. For continuous variables, significance was calculated using the Student t-test. A linear regression model was applied to identify associations of the type and extent of motion with image quality scores. Kappa statistics were used to assess intra- and inter-rater agreement. Chi-square testing was used to analyze the impact of age and sex on head movement. Results: All CBCT images were acquired in a 10-month period. In 24% of the investigations, movement was recorded (acceleration: >0.10 [m/s2]; angular velocity: >0.018 [°/s]). In all examined regions of interest, head motion during CBCT acquisition resulted in significant impairment of image quality (P<0.001). Movement in the horizontal and vertical axes was most relevant for image quality (R2>0.7). Conclusion: Relevant head motions during CBCT imaging were frequently detected, leading to image quality loss and potentially impairing diagnosis and therapy planning. The presented data illustrate the need for digital correction algorithms and hardware to minimize motion artefacts in CBCT imaging.