Detection accuracy of proximal caries by phosphor plate and cone-beam computerized tomography images scanned with different resolutions

This study was carried out to assess whether the spatial resolution has an impact on the detection accuracy of proximal caries in flat panel CBCT (cone beam computerized tomography) images and if the detection accuracy can be improved by flat panel CBCT images scanned with high spatial resolution when compared to digital intraoral images. The CBCT test images of 45 non-restored human permanent teeth were respectively scanned with the ProMax 3D and the DCT Pro scanners at different resolutions. Digital images were obtained with a phosphor plate imaging system Digora Optime. Eight observers evaluated all the test images for carious lesion within the 90 proximal surfaces. With the histological examination serving as the reference standard, observer performances were evaluated by receiver operating characteristic (ROC) curves. The areas under the ROC curves were analyzed with two-way analysis of variance. No significant differences were found among the CBCT images and between CBCT and digital images when only proximal enamel caries was detected (p = 0.989). With respect to the detection of proximal dentinal caries, significant difference was found between CBCT and digital images (p < 0.001) but not among CBCT images. The spatial resolution did not have an impact on the detection accuracy of proximal caries in flat panel CBCT images. The flat panel CBCT images scanned with high spatial resolution did not improve the detection accuracy of proximal enamel caries compared to digital intraoral images. CBCT images scanned with high spatial resolutions could not be used for proximal caries detection.     

锥束CT在正颌外科中的应用

目的:探讨锥束CT(cone beam computer tomography,CBCT)在正颌外科中的应用价值。方法:对20例正颌手术患者术前行CBCT扫描,提取不同的影像资料,定位正颌手术重要解剖结构位置。结果:该成像技术对正颌手术患者上颌骨翼腭管和下颌管的位置关系等重要结构均有良好的显示,为正颌手术方案设计提供了放射学的颌骨评估基础,指导了临床正颌外科的定位设计。结论:CBCT可为正颌外科提供更精准的结构解剖影像,极大地提高了手术的准确性与安全性。     

Accuracy and validity of stitching sectional cone beam computed tomographic images

To determine whether three-dimensionally reconstructed images of skulls created by stitching multiple cone beam computed tomographic (CBCT) images are as accurate as single images obtained using multidetector computed tomography (MDCT), 10 skull models were scanned using an optical three-dimensional scanner, MDCT, and CBCT. Cone beam CT images at 3 different levels of the skull were manually superimposed and stitched. The reconstructed CBCT images at each level were aligned and fused using computer software and then compared to the nominal reference image obtained from the optical three-dimensional scanner by determining positional errors. The reconstructed MDCT images were also compared, and the differences in the mean errors for the 3 image types compared with the nominal reference image data were evaluated. There were no significant differences between the MDCT images and the manually merged CBCT images (Wilcoxon signed rank test, P = 0.017). In contrast, there were significant differences between the MDCT images and the software-aligned CBCT images (P = 0.005). Manual stitching of CBCT sectional images at different levels can provide accurate anatomic details of the oral and maxillofacial regions.     

锥形束CT用于评价离体牙槽骨高度准确性的研究

目的评价锥形束CT（CBCT）图像测量离体牙槽骨高度的准确性和可重复性,为其应用于牙周病的临床诊断和预后评价提供理论依据。方法使用CBCT对8具干燥下颌骨进行扫描,在图像上重复测量236个人工选择标志点处牙槽嵴顶至釉牙骨质界的距离;同时使用游标卡尺直接测量以上标志点处牙槽嵴顶至釉牙骨质界的距离。应用SPSS 13.0软件对所得数据进行统计学分析。结果CBCT图像对牙槽嵴顶至釉牙骨质界距离的重复测量结果间差异无统计学意义（P>0.05）;CBCT图像与游标卡尺对牙槽嵴顶至釉牙骨质界距离的测量结果间差异也无统计学意义（P>0.05）。结论CBCT图像可清晰显示牙与牙槽骨之间的空间解剖关系,其对牙槽骨高度体外测量的结果具有准确性和可重复性。     

Application of cone beam CT 3D images to cephalometric analysis

Orthodontic diagnosis is currently based primarily on two-dimensional (2D) measurements. The development of maxillofacial cone beam X-ray computed tomography (CBCT) has promoted the use of three-dimensional (3D) measurements for orthodontic diagnosis. This technology is also expected to generate new analytic methods aiming at establishing optimal occlusion according to the individual's maxillary shape and function. However, during the transitional stage from 2D to 3D measurements, it is necessary to relate 3D data to existing data analysis methods (e.g., lateral cephalogram) for the assessment of skeletal and dental relationship. Our objectives were to develop a new cephalometric analysis method based on 3D data obtained by CBCT from four aspects: (1) measurement of magnification of cephalogram, (2) assessment of the dimensional accuracy of CBCT images, (3) development of a method of cephalometric analysis using CBCT images and (4) comparison of cephalometric analytical values obtained from CBCT images with those obtained from existing cephalograms. The results demonstrated that our analytical method facilitated cephalometric analysis of CBCT images and therefore allowed direct comparison of CBCT images with existing cephalograms. Cephalometric analysis using CBCT images resulted in a smaller range of inter-operator measurement variability than that using conventional cephalograms.     

Maxillofacial cone beam computed tomography: essence, elements and steps to interpretation

Maxillofacial cone beam computed tomography (CBCT) is one of the most significant advances in dental imaging since rotational panoramic radiography. While the acquisition of CBCT data is technically simple, numerous parameters should be considered so that CBCT imaging is performed appropriately and 'task specific'. This involves an understanding of not only exposure (e.g. geometric and software parameters to minimize patient dose, while sustaining diagnostic image quality) but also image formatting options to maximize image display. CBCT images contain far more detailed information of the maxillofacial region than do panoramic or other 2-D images and necessitate a thorough knowledge of the 3-D anatomy of the region and considerations of variability in the range of the anatomically normal. These principles, procedures and protocols, together with the interpretation of CBCT images form the basis of best practices in maxillofacial CBCT imaging. This communication aims to provide: (1) an overview of the fundamental principles of operation of maxillofacial CBCT technology; (2) an understanding of 'task specific' equipment, image selection and image display modes; and (3) a systematic methodology for sequencing interpretation of CBCT images.     

三维头影测量的研究现状与展望

随着锥体束CT(cone beam computed tomography,CBCT)在正畸领域的广泛使用,越来越多正畸医生开始研究使用CBCT影像进行三维头影测量分析.三维头影测量分析是需要基于CT或者CBCT获得患者的三维头颅影像,并使用具有三维分析功能的软件进行测量与分析.本文就三维头影测量的定义与发展、头颅定位、定点、测量项目及参考值的确定和影像重叠五个方面进行综述,并对其今后发展方向进行展望.     

Clinical Factors Associated with Apical Periodontitis Visible on Cone-beam Computed Tomography but Missed with Periapical Radiographs: A Retrospective Clinical Study

IntroductionCone-beam computed tomographic (CBCT) imaging is useful in detecting apical periodontitis, which is often missed in periapical (PA) radiographs. This study aimed to identify preoperative predictors correlated with the presence of apical periodontitis visible only in CBCT images and to investigate the important characteristics of such lesions.MethodsIn total, 332 consecutive patients with both PA radiographs and CBCT images were enrolled in this study. The patients’ clinical charts were reviewed retrospectively to collect information regarding their symptoms and diagnoses. Periapical lesions were assessed using a modified CBCT PA index by 2 endodontists. Patient-related factors (age, sex, and symptoms) and tooth-related factors (tooth type, location, pulp status, and pulpal diagnosis) were assessed to determine their relationships with the presence of apical periodontitis visible only in CBCT images.ResultsApical periodontitis was detected in 24.6% and 35.5% of untreated teeth by PA radiographs and CBCT images, respectively. In a multivariate logistic regression analysis, pulp necrosis was significantly correlated with the presence of apical periodontitis visible only in CBCT images (odds ratio = 5.401; 95% confidence interval, 1.911–15.265; P = .001); the involvement of molars showed borderline nonsignificant correlation (odds ratio = 2.843; 95% confidence interval, 0.990–8.164; P = .052). Lesion sizes smaller than 2 mm in diameter and the involvement of molars were significant factors of lesions visible only in CBCT images (P < .05).ConclusionsPulp necrosis was a preoperative predictor of apical periodontitis visible only in CBCT images. This research could provide a proper indication for CBCT imaging at diagnostic stages.     

能谱锥形束CT减少口腔金属伪影的效果评价

目的: 评价基于口腔能谱锥形束CT（CBCT）的虚拟单色成像技术在减少金属伪影方面的价值。方法: 选择46例带有口腔金属物的患者,并随机分为A、B 2组,其中A组用口腔能谱CBCT进行成像,B组用传统口腔CBCT进行成像。图像分析指标包括图像的方差（STD）和金属伪影指数（MAI）。所得数据采用SPSS 25.0软件包进行独立样本或配对t检验。结果: 口腔能谱CBCT的虚拟单色图像的MAI值为57.7,低于该设备生成的传统图像的MAI值（81.8）,且具有统计学差异（P<0.05）。此外,口腔能谱CBCT的虚拟单色图像的MAI值（57.7）也低于传统CBCT图像的MAI值（157.1）,且具有统计学差异（P<0.05）。结论: 口腔能谱CBCT的虚拟单色成像技术能有效减少金属伪影。     

Application of cone beam computed tomography in oral and maxillofacial surgery

In the past decade, the utility of cone beam computed tomography (CBCT) images in oral and maxillofacial surgery has seen continuous increase. However, CBCT images are not always able to replace other imaging modalities. Based on the current published knowledge, this paper discusses advantages and limitations of CBCT images in the diagnosis and surgical planning of dentoalveolar procedures, odontogenic cysts, benign and malignant tumours, inflammatory changes, orthognathic surgery, maxillofacial trauma, sinus disorders, and systemic and osseous conditions that manifest in the maxillofacial area. This paper also suggests alternative imaging modalities when CBCT images are not adequate for surgical planning.     

CBCT髓室底3D重建在牙髓根尖周疾病中的应用

目的 分析评估采用CBCT(锥形束计算机断层扫描,Cone Beam Computed Tomography)进行髓室底3D重建在牙髓根尖周疾病中的应用价值.方法 对我院口腔科于2015年11月至2016年3月所做的15例磨牙CBCT使用OnDemand 3D Dental软件进行3D髓室底重建并分析图像,与传统CBCT断层图像进行对比,观察其在临床中的作用.结果 CBCT髓室底3D重建技术能为临床医生提供直观信息,显著提高诊治效率.结论 CBCT髓室底3D重建可明确髓室底情况,确定根管口位置,为根管治疗提供优于传统CBCT断层图像的直观信息.     

Four-rooted maxillary first molar having C-shaped palatal root canal morphology evaluated using cone-beam computerized tomography: a case report

The aim of this article was to present an endodontically managed maxillary first molar with unusual C-shaped palatal root morphology confirmed by cone-beam computerized tomography (CBCT) images. CBCT axial images showed the presence of C-shaped palatal root canal anatomy with a palatal root bifurcation at the apical third. The evaluation of CBCT images can result in better understanding of root canal anatomy, which enables the clinician to investigate the root canal system and to clean, shape, and obturate it more effectively.     

Validity and reproducibility of cephalometric measurements performed in full and hemifacial reconstructions derived from cone beam computed tomography

Abstract Objective: To test the reproducibility and validity of angular measurements from virtual lateral cephalometric radiography (LCR) reconstructions (full and hemifacial on both sides) derived from cone beam computed tomography (CBCT). Materials and Methods: Fifty-eight CBCT and LCR images were selected. CBCT volume data were imported into Nemotec software, and virtual LCR images and tomographic slices from CBCT images were assessed. Three observers digitized landmarks used for 12 angular measurements in CBCT images from all patients at two different times. The LCR were evaluated by two examiners, and the mean of the measurements was used as the gold standard. Results: The virtual hemifacial LCR of tomographic slices on the right side showed statistically different higher measures. The same modality on both sides showed less absolute differences for most measures except FMIA and interincisal angles. All modalities had excellent reproducibility. Conclusions: The angular measurements made on virtual LCR reconstructions derived from CBCT are reproducible and valid. Some advantage was found over virtual hemifacial LCR on both sides of the image, mainly in its handling facility.     

健康成人颞下颌关节间隙许勒位片和锥形束CT测量比较分析

目的比较颞下颌关节矢状位锥形束CT（cone beam computed tomography,CBCT）外1/3层面图像与许勒位片关节间隙及髁突在关节窝中的位置,探讨许勒位片是否可以准确地反映颞下颌关节外1/3层面关节间隙及髁突在关节窝中的位置。方法对经严格筛选、符合试验设计的30名健康成人的60侧颞下颌关节同时进行CBCT和许勒位片检查,使用AutoCAD计算机软件,采用两种线距定量测量方法对60侧颞下颌关节矢状位CBCT外1/3层面图像和许勒位片影像进行关节间隙测量,并对结果进行比较分析。结果两种测量方法均表明颞下颌关节许勒位片和矢状位CBCT关节外1/3层面图像左侧和右侧关节前、上、后间隙分别对应比较,差异均无统计学意义（P均大于0.05）;且许勒位片与CBCT关节外1/3层面图像loge（P/A）值比较,差异亦无统计学意义（P大于0.05）。结论许勒位片可以较准确地反映颞下颌关节外1/3层面关节间隙及髁突在关节窝中的位置。目前许勒位片检查仍可做为颞下颌关节间隙和髁突位置判断的一种有参考价值的检查方法。     

锥形束CT在颌骨囊性疾病诊断中的意义

目的探讨锥形束计算机体层摄影术(CBCT)在口腔颌面部囊性疾病诊断中的临床价值。方法收集53例颌骨囊性病变病例的CBCT影像资料,利用CBCT三维影像重建技术,观察颌骨囊性病变与牙根累及的关系、牙根吸收情况、病变内含牙、以及病变与下颌神经管、鼻底、上颌窦的关系等,并在术中进行验证。结果 CBCT能清晰的显示颌骨囊性病变与牙根的相互累及关系,埋伏牙相关信息以及病变与颌骨内重要结构的空间位移情况。结论 CBCT扫描能够全面提供颌骨囊性病变的影像学信息,可为颌面外科的临床手术提供可靠依据。     

Three‐dimensional imaging as a pre‐operative tool in decision making for furcation surgery

Aim: To investigate the use of cone beam computed tomography (CBCT) in assessing furcation involvement (FI) and concomitant treatment decisions in maxillary molars. Material and Methods: Twelve patients with generalized chronic periodontitis were consecutively recruited and CBCT was performed in maxillary molars (n=22) with clinical FI and increased probing pocket depths. CBCT images were analysed and FI, root length supported by bone and anatomical features were evaluated. FI and treatment recommendations based on clinical examinations and periapical radiographs were compared with data derived from CBCT images. Results: The estimated degree of FI based on clinical findings was confirmed in 27% of the sites, while 29% were overestimated and 44% revealed an underestimation according to CBCT analyses. Among degree I FI, 25% were underestimated, among degree II and II–III, the underestimation was as high as 75%, while all sites with degree III FI were confirmed in the CBCT. Discrepancies between clinically and CBCT‐based therapeutic treatment approaches were found in 59–82% of the teeth, depending on whether the less invasive or the most invasive treatment recommendation was selected for comparison. Conclusions: CBCT images of maxillary molars may provide detailed information of FI and a reliable basis for treatment decision.     

Comparative evaluation of cone beam CT and micro-CT on blooming artifacts in human teeth filled with bioceramic sealers

Aim

To assess blooming artifacts caused by root canal sealers in CBCT images compared with those that appeared in micro-CT scan images used as references.

Materials and method

Thirty freshly extracted human mandibular central incisors were used. Root canals were prepared with nickel titanium files with an ISO size 40/0.06 taper and filled with a single cone (40/0.06 taper) and three different sealers. The samples were divided into the following three groups with 10 roots each: (I) AH Plus sealer; (II) Sure Seal Root; and (III) Total BC sealer. Teeth were scanned with the same voxel sizes (0.2 mm) in different CBCT devices and the micro-CT images were acquired as reference images.

Results

Significantly different results in terms of blooming artifacts were detected between CBCT and micro-CT images, as well as among the CBCTs images. The canals filled with AH Plus sealer showed more blooming artifacts than those filled with bioceramic sealers (p < 0.05). Additionally, the worst blooming artifact was observed when the images were acquired with lower kilovoltage peak.

Conclusion

The appearance of blooming artifacts is dependent on sealer and CBCT, and their effects are significantly worse than they are in micro-CT images. The differential effect of different sealers and distinct CBCT protocols should be further investigated to enable the use of bioceramic sealers without a significant impact on post-treatment imaging.

Clinical relevance

Root canal sealers showed a different extent of blooming artifact in CBCT images. Hence, researchers and clinicians should be aware of these artifacts before conducting endodontic evaluations using CBCT images.

     

个别正常牙合CBCT与头颅侧位片头影测量的比较分析

目的比较哈尔滨地区个别正常牙合CBCT与头颅侧位片的头影测量结果的差异性。方法选择哈尔滨地区30名个别正常牙合志愿者,分别拍摄CBCT和头颅侧位片。CBCT图像导入Simplant软件进行三维头影测量,头颅侧位片用硫酸纸描图定点进行二维头影测量,两种方法均测量Steiner和Jarabak分析法的24个测量项目。分析两者测量结果差异性。结果CBCT测量与头颅侧位片测量结果中,15个测量项目差异具有统计学意义,分别为:SNB角、SND角、UI-NA角、UI-NA距、Go Gn-SN角、Pg-NB距、SE距、N-S-Ar角、S-Ar-Go角、Ar-Go-Me角、三角之和、S-Ar距、Go-Me距、N-Me距、S-Go距。结论CBCT测量与头颅侧位片测量结果中,大部分测量值存在明显差异。该文初步推断哈尔滨地区Steiner和Jarabak分析法的CBCT三维头影测量参考值范围。     

CBCT头颅侧位片在头影测量中可重复性的研究

目的：比较锥形束CT（CBCT）三维头影测量与CBCT转化头颅侧位片（Cephalogram from CBCT,CCB）及数字化X线头颅侧位片（Digital Cephalogram,DC）头影测量的可重复性和可靠性。方法：对一名成年人进行CBCT扫描并拍摄数字化X线头颅侧位片。使用Invivo Dental 5．0软件对CBCT图像进行三维测量;CCB和DC采用Winceph 8．0软件进行二维头影测量。选择常用测量项目15项,同一操作者对3种图像测量15次。对CBCT,CCB及DC测量可重复性进行统计学分析,三者间可重复性差异采用方差分析。结果：CCB测量可重复性优于CBCT和DC（P＜0．05）。15个测量项目中CCB有8个测量项目精确度明显高于CBCT和DC。结论：CBCT三维影像能真实反映颅颌面空间结构,弥补二维图像失真,解剖结构重叠的不足。 CCB测量可重复性优于CBCT三维测量和传统X线头颅侧位片二维测量,在三维测量系统完善前,CCB是头影测量由二维向三维过度的重要测量方法。     

下颌神经管在CBCT与曲面体层片上的一致性评价

目的:对比分析下颌神经管在CBCT与曲面体层片上可见性的一致性,探讨影响下颌神经管在图像上可见性的非病变因素。方法:选取2013年12月~2014年2月期间在华西口腔医院同时拍摄了CBCT与曲面体层片的患者92例,由2位放射科医师同时观察患者的CBCT片与曲面体层片。把CBCT及曲面体层片上的下颌神经管从颏孔至下颌升支前缘处平分为1、2、3三个区域,分为0、1、2、3四个等级的分对下颌神经管的可见性进行评分。结果:2位医师间的内部一致性检验符合标准。CBCT上,区域1平均得分为2.120,区域2为2.337,区域3为2.533;曲面体层片上,区域1平均得分为1.772,区域2为1.973,区域3为2.207。越往后区域可见性越高。结论:CBCT对下颌神经管的可见性显著高于曲面体层片,仅有1％的下颌神经管在曲面体层片上可见,在CBCT上不可见。下颌神经管的可见性与年龄呈相关性,年龄越大,可见性越低。