影响数字化X线根尖片影像质量的原因分析

目的:研究影响数字化X线根尖片摄像质量的因素。方法:采用Kodak 2100数字成像系统,对200例患者的218颗牙齿行根尖片拍摄。结果:与传统的X线根尖片胶片摄影技术比较,数字化摄影技术在曝光时间上减少80%～87%,218张根尖片质量评价:甲级172张,乙级21张,丙级25张。结论:根尖片数字化X线摄影技术具有传统X线根尖片摄影技术无法比拟的优势。     

根尖片数字化X线摄影技术及其临床应用

目的 研究根尖片数字化Ｘ线摄影技术及其临床应用。方法 采用Ｄｉｇｏｒａ数字化摄影设备,对８８例患者的１０５颗牙齿行根尖片拍摄,结果 与根尖片传统摄影技术比较,曝光时间减少５０％～８０％,质量评价：甲级８８张,乙级１２张,丙级５张。结论 在片数字化Ｘ线摄影技术具有传统根尖片摄影技术所不具备的优越性,因而为口腔临床及科研提供了一种新的检查手段。     

锥形束CT辅助诊断根尖囊肿累及范围的临床应用研究

目的：分析锥形束CT（CBCT）辅助诊断慢性根尖囊肿累及范围的临床应用效果。方法：选取2013年4月－2014年4月诊断为慢性根尖囊肿的CBCT三维重建影像资料42例，观察X线根尖片及CBCT三维重建影像资料，综合评价CBCT在辅助诊断慢性根尖囊肿累及范围中的应用效果。结果：CBCT诊断慢性根尖囊肿累及范围的能力显著优于X线根尖片，42例均能通过CBCT准确诊断囊肿累及患牙，并于根管治疗后根尖囊肿如期愈合。结论：CBCT能够辅助诊断慢性根尖囊肿的累及范围，并指导临床医生判断受累患牙。     

口腔数字成像系统X线传感器定位器的研制和临床应用

目的研究数字化根尖片的固位方法和临床应用。方法采用ODIS-I型口腔数字成像系统,对随机分成A、B两组的72例阻生牙患者拍片。A组使用定位器拍片,B组不使用定位器拍片。结果A组拍片质量优于B组(P<0.001),A组拍片时间少于B组(P<0.001)。结论使用X线传感器定位器拍片可提高拍片质量,缩短拍片时间,方便临床操作。     

X线投照角度对根尖片诊断牙根吸收影响的研究

目前，根尖片和曲面断层片是诊断牙根吸收的常用方法。与曲面断层片相比，根尖片的投照技术能够保证获得更加准确的影像，更加有效地诊断正畸牙根吸收。但是在拍摄根尖片时，有许多因素可能造成影像的失真。这些因素包括：X线的投照角度、牙齿-胶片位置关系、焦点-胶片距离、牙齿-胶片距离等。其中，X线的投照角度最难控制。     

口腔直接数字成像图像质量的评价

目的:根据直接数字成像系统在口腔科的应用情况,进行回顾性分析,评价其质量等级.方法:应用Trophy elitvs RVG口腔数字成像系统检查1195例患者,包括龋病、牙周病、根尖周病、牙外伤及牙发育异常等疾病,对成像质量进行4级评估.结果:口腔数字成像系统操作简便,方便保存,X线成像所需放射剂量明显减少;共供摄取牙片1587张.其中Ⅰ级(优良)占92.3%.Ⅱ级(欠佳)占6.3%,Ⅲ级(勉强可进行临床诊断)和Ⅳ级(无法进行临床诊断)合计为1.14%.结论:获得的不同牙位和不同的图像质量基本优良,可以满足临床诊断要求,但尚需改进影像感受器性能,以提高摄片质量.     

对比数字化X线牙片与CBCT对牙根纵裂诊断价值分析

目的：对比数字化X线牙片与CBCT对牙根纵裂的诊断价值。方法：以济南市口腔医院口腔内科的50例牙根纵裂患者为研究对象。将患者分别定义为观察组和对照组。对照组行数字化X线牙片检查,观察组行CBCT检查。分别根据x线片诊断标准和CT诊断标准对影像学检查结果做出独立判断。再根据牙根纵裂临床诊断金标准分别对x线根尖片的诊断结果和CBCT检查的诊断结果进行比较,得出两组真阳性（TP）、假阳性（FP）、真阴性（TN）、假阴性（FN）,计算敏感性、特异性、阳性预测值、阴性预测值。结果：牙根纵裂临床诊断金标准判断结果显示：本组50例患者中,牙齿纵裂确定46例,排除4例。X线根尖片检查诊断牙根纵裂的敏感度为77％,特异性为75％,阳性检出率为96．88％,阴性检出率为16．67％;CBCT诊断牙根纵裂的敏感度为95．65％,特异性为100％,阳性检出率为100％,阴性检出率为66．67％。CBCT扫描诊断牙根纵裂的敏感度、特异性、阳性检出率明显大于X线根尖检查（P〈0．01）。CBCT扫描诊断牙根纵裂的阳性检出率大于x线根尖片检查（P〈0．05）。结论：在牙根纵裂的临床诊断中,CBCT诊断的敏感度、特异性、阳性检出率、阴性检出率均高于x线牙片,具有更高的临床应用价值。     

口腔数字成像系统在牙周病疗效观察中的评价

目的:评价数字化成像技术在牙周病疗效观察中的作用。方法:应用ODIS-Ⅰ口腔数字成像系统对135例牙周病患者的215个区域拍摄的图像进行质量判定;并应用该系统的图像处理技术对其中33例患牙的图像进行治疗前后牙槽骨吸收率的测定,7例患牙治疗前后的定位根尖片图像进行数字减影分析。结果:口腔数字成像系统X线成像所需放射剂量明显减少,获得的图像质量基本优良,对牙周组织变化的敏感性高于普通X线牙片,该系统的图像处理技术可提高牙周病诊断和疗效观察水平。结论:口腔数字成像系统是牙周病疗效观察的有效手段。     

口腔医学生根尖片投照失败原因分析

根尖片是口腔科医师诊断牙患的重要手段，是口腔临床中应用最多的一种X线片。根尖片投照技术是口腔医学专业学生必须掌握的基本技能之一。根尖片的密度、清晰度、对比度和失真度的好坏直接影响到疾病的诊断与治疗。笔者把近三个月2002级学生在我科实习所拍摄的3378张牙片进行分析，研究根尖片投照失误的类型及其与牙位的关系，以便发现教学过程中存在的问题并予以改进，为今后实习学生减少失误，提高根尖片的质量，降低废片率、减少患者不必要的X线照射提供帮助。     

ODIS-I型口腔数字成像系统的临床应用评价

目的：评价数字化成像技术在口腔病变检查中的应用效果。方法：对于应用ODIS-I口腔数字成像系统拍摄的578例不同分区的牙齿病变的图像进行成像质量判定。结果：口腔数字成像系统X线成像所需放射剂量明显减少，获得的图像质量基本优良，上颌前牙的影像最佳，下颌阻生牙的影像较差。结论：应用ODIS-I口腔数字成像系统拍摄的各类牙齿病变的图像可以基本满足临床检查的需要。尚有待于进一步提高口腔数字成像系统的性能。     

In vitro radiographic determination of distances from working length files to root ends comparing Kodak RVG 6000, Schick CDR, and Kodak insight film

Previous studies suggest that digital and film-based radiography are similar for endodontic measurements. This study compared the accuracy and acceptability of measured distances from the tips of size #10 and #15 files to molar root apices in cadaver jaw sections using the newly developed Kodak RVG 6000, and the Schick CDR digital systems to digitized Kodak film. Standardized images were taken of files placed 0.5 to 1.5 mm short of true radiographic lengths. Images were imported into Adobe PhotoShop 7.0, thereby blinding observers who measured distances from files to root apices and assessed images for clarity (acceptability). Repeated measures ANOVA and Tukey-Kramer post hoc tests demonstrated that Kodak RVG 6000 images with enhanced contrast produced significantly less measurement error than unenhanced contrast Schick CDR images (p < 0.05) and significantly higher acceptability ratings than all other systems (all p < 0.002). Among these conditions, the newly developed Kodak RVG 6000 system provided the best overall images.     

A comparison of five radiographic systems to D-speed film in the detection of artificial bone lesions

The purpose of this study was to compare three direct digital sensors (Kodak 6100 [Rochester, NY], Schick CDR [Long Island City, NY], and Dexis PerfectSize [Alpharetta, GA]), a phosphor plate system (OpTime; Milwaukee, WI), and F-speed film to standard D-speed film in the detection of artificial bone lesions prepared in mandible bone sections. Artificial bone lesions were prepared at varying depths in the cortical bone. Radiographs were randomly presented to nine different observers. Logistic regression analysis indicated significant differences in lesion detection among the radiographic systems at the mean percentage of cortical bone remaining. The Kodak filtered, Schick filtered, OpTime unfiltered, Schick unfiltered, and Dexis filtered images were significantly better at lesion detection compared with D-speed film.     

A laboratory comparison of three imaging systems for image quality and radiation exposure characteristics

AIM: To measure and compare the relationships between image quality and X-ray exposure for three types of intraoral imaging system (conventional film, phosphor plate system and CCD-based system). METHODOLOGY: Kodak 'Insight' F-speed film, Digora FMX (phosphor plate system) and Visualix USB (CCD system) were used to produce series of radiographic images of two tooth-bearing jaw specimens (maxillary molar and mandibular molar regions) at a range of X-ray exposures from 10 ms to 2000 ms (all at 6 mA and 60 kV). Digital images were viewed from a computer monitor and films viewed on a conventional light box. Five observers scored each image using a five-point subjective image quality scale (0-4). RESULTS: Optimum image quality (4) was seen for conventional film. Neither digital system achieved this score at any exposure, achieving in both cases a maximum mean score of 3.1 (adequate visualization). The two digital systems, however, provided adequate visualization at substantially lower exposure times. Dose reduction over conventional film for maximum quality images with Visualix USB was 20%, but for Digora FMX it was 70%. All three systems gave acceptable (quality score of two or higher) images over a broad range of exposures. CONCLUSIONS: In terms of subjective image quality, F-speed film performed better than the two digital systems, but this must be weighed against the ability of the two digital systems to give adequate image quality at lower radiation doses.     

Subjective image quality comparison between two digital dental radiographic systems and conventional dental film

ObjectivesDigital radiography has become an integral part of dentistry. Digital radiography does not require film or dark rooms, reduces X-ray doses, and instantly generates images. The aim of our study was to compare the subjective image quality of two digital dental radiographic systems with conventional dental film.Materials & methodsA direct digital (DD) ‘Digital’ system by Sirona, a semi-direct (SD) digital system by Vista-scan, and Kodak ‘E’ speed dental X-ray films were selected for the study. Endodontically-treated extracted teeth (n = 25) were used in the study. Details of enamel, dentin, dentino-enamel junction, root canal filling (gutta percha), and simulated apical pathology were investigated with the three radiographic systems. The data were subjected to statistical analyzes to reveal differences in subjective image quality.ResultsConventional dental X-ray film was superior to the digital systems. For digital systems, DD imaging was superior to SD imaging.ConclusionConventional film yielded superior image quality that was statistically significant in almost all aspects of comparison. Conventional film was followed in image quality by DD, and SD provided the lowest quality images. Conventional film is still considered the gold standard to diagnose diseases affecting the jawbone.RecommendationsImproved software and hardware for digital imaging systems are now available and these improvements may now yield images that are comparable in quality to conventional film. However, we recommend that studies still use more observers and other statistical methods to produce ideal results.     

Sensitometric properties of Agfa Dentus OrthoLux, Agfa Dentus ST8G, and Kodak Ektavision panoramic radiographic film

OBJECTIVES: The purpose of this study was to compare the sensitometric properties of and visualization of anatomical structures with Agfa OrthoLux green-sensitive panoramic radiographic film, Agfa ST8G green sensitive panoramic radiographic film, and Kodak Ektavision green-sensitive panoramic radiographic film used in combination with an Agfa Ortho Regular 400 imaging screen, Kodak Ektavision imaging screen, and Kodak Lanex Regular imaging screen. METHODS: The density response and resolution of panoramic radiographic film/intensifying screen combinations was evaluated by means of Hunter and Driffield curves, modulation transfer functions, and noise-equivalent number of quanta. Image clarity of selected anatomical structures was rated independently by 6 oral and maxillofacial radiologists. RESULTS: The ISO speed for the Agfa OrthoLux panoramic radiographic film combinations was the fastest, and the ISO speed for the Kodak Ektavision green-sensitive panoramic radiographic film combinations was the slowest. The average gradient for the Agfa ST8G systems was relatively steep in comparison with those for the other film/screen combinations. The modulation transfer functions for the Kodak Ektavision film were higher than those for the other films, irrespective of the screen combination used, and those for Agfa OrthoLux film were slightly higher than those for Agfa ST8G film. The noise-equivalent number of quanta for the Agfa ST8G film/screen combinations was lower than those for the other film/screen combinations. The noise-equivalent number of quanta for the Kodak Ektavision film/screen combinations was well within the high-frequency range, whereas Agfa OrthoLux combined with either the Kodak Ektavision imaging screen or the Kodak Lanex Regular imaging screen produced a noise-equivalent number of quanta similar to those of the Kodak Ektavision film/screen combinations in the low-frequency range. Agfa OrthoLux was perceived to provide clearer images of the selected anatomical details than Agfa ST8G, and the Agfa OrthoLux/Agfa Ortho Regular 400 combination was not significantly different from the Kodak Ektavision/Kodak Lanex Regular combination in terms of perceived image quality. CONCLUSION: Agfa OrthoLux is an improvement over Agfa ST8G in film speed, spatial resolution, granularity, and perceived diagnostic image quality. The Agfa OrthoLux/Agfa Ortho Regular 400 combination did not exceed the Kodak Ektavision film/Kodak Ektavision imaging screen combination in resolution, granularity, or perceived image quality.     

Direct digital radiography for the detection of periapical bone lesions: a clinical study

Abstract The aim was to compare the observer performance of direct digital radiography, with and without image processing, with that of conventional radiography, for the detection of periapical bone lesions. For 50 patients, a conventional periapical radiograph using E-speed film was taken. Then, a direct digital image of the same area was made. The images presenting the periapical bone tissue of 59 roots were assessed by seven observers using a 5-point confidence scale. The digital images were first presented as original images, with default contrast and brightness set by the computer system. Following this, the observers were allowed to use the processing facilities for greyscale treatment. The results for original and processed direct digital images and for conventional radiographs were compared by Receiver Operating Characteristic (ROC) analysis. The area under the ROC curve, calculated as P(A) value, was 0.88 for conventional film, 0.82 for original digital images and 0.78 for processed images. Corresponding A_z values were slightly higher, 0.89, 0.84 and 0.81. Statistically significant differences between ROC areas calculated as P(A) values for the methods were found. Comparison between A_z values showed no significant differences between conventional radiographs and original digital images, whereas the difference between A_z values for original and processed digital images was still significant. It was concluded that conventional film radiography performed slightly better for the detection of periapical bone lesions than direct digital radiography and that image processing did not improve the observer performance.     

A clinical trial of a rare earth screen/film system in a periapical cassette

In a clinical trial, a slow rare earth screen/film system (Siemens Titan 2D/Kodak XG) was used to obtain intraoral radiographs at conventional monitoring stages in endodontic treatment. The screen film image proved to be an effective substitute for the direct-exposure Ultraspeed periapical film. The intraoral cassettes, designed and fabricated for the study, were an adaptation of the flexible, vacuum-sealed cassettes used in mammography. It is believed that when a practicable periapical cassette is manufactured, many additional indications for the system are probable. Major reductions in patient exposure of at least 85% to 90% per periapical film would be effected.     

Evaluation of chronic periapical lesions by digital subtraction radiography by using Adobe Photoshop CS: a technical report

The purpose of this study was to describe a new technique by using Adobe Photoshop CS (San Jose, CA) image-analysis software to evaluate the radiographic changes of chronic periapical lesions after root canal treatment by digital subtraction radiography. Thirteen upper anterior human teeth with pulp necrosis and radiographic image of chronic periapical lesion were endodontically treated and radiographed 0, 2, 4, and 6 months after root canal treatment by using a film holder. The radiographic films were automatically developed and digitized. The radiographic images taken 0, 2, 4, and 6 months after root canal therapy were submitted to digital subtraction in pairs (0 and 2 months, 2 and 4 months, and 4 and 6 months) choosing "image," "calculation," "subtract," and "new document" tools from Adobe Photoshop CS image-analysis software toolbar. The resulting images showed areas of periapical healing in all cases. According to this methodology, the healing or expansion of periapical lesions can be evaluated by means of digital subtraction radiography by using Adobe Photoshop CS software.     

A digital SLR or intra-oral camera: preference for acquisition within an image analysis system for measurement of disclosed dental plaque area within clinical trials

Objectives:  The aim of this investigation was to compare the accuracy and reproducibility of images acquired from two types of camera (digital SLR camera, Kodak DCS410, KJP, UK and an intra-oral camera, Schick Technologies, UK) for application within an imaging system used for the quantification of disclosed dental plaque.
Methods:  Subjects refrained from brushing their teeth for 24 h. Their teeth were then disclosed with Erythrosin FDC Red 3 and duplicate sets of images were obtained by each examiner of the upper central and lateral incisors. Images were then saved and measured for dental plaque area. These data were used to calculate reliability.
Results:  No statistically significant bias in the measurements of plaque area was found. The reliability results showed the method was reliable. However, the image analysis system incorporating the 35 mm SRL camera was more reliable for both operators, as demonstrated by their intra-operator results. This was also collaborated by the inter-operator results.
Conclusion:  In this investigation the digital SLR camera combined with the image analysis system and frame permitted greater reliability of dental plaque surface area measurements than the digital intra-oral camera. This conclusion was derived both from the reliability data and from the perceived ease of use and flexibility of both camera types. When combined with the use of the custom-made frame, the images using the digital SLR camera were highly reproducible, confirming the systems application within clinical trials.     

An in vitro comparison of 10 radiographic methods for working length estimation

The aim of this in vitro study was to assess the efficacy of 10 currently available methods of producing radiographic images, two conventional and eight rapid, in working length estimation. Thirty extracted teeth comprising 42 root canals were mounted in blocks of poly(methylmethacrylate) and access cavities prepared. A size 15 Hedstrom file was inserted into each root canal and sealed into position. Each tooth was imaged by 10 methods: combinations of conventional (D^? and E^? speed) film processed with conventional manual chemistry or two proprietary brands of rapid processing chemistry (Westone Rapid Dental and Kodak ‘Rapid Access’), Super X30 packet processed film, Hanshin Hi-Fi and Nix NF45-100 films processed using their respective manufacturers' monobath solutions, and the Sens-A-Ray digital X-ray system. Comparisons of length of file visible were made between the D-speed films (conventionally processed using Kodak chemistry) and the nine other radiographic methods. No significant differences in percentage length of file seen were found between D-speed film processed with conventional chemistry and E-speed film processed with the same chemistry or between D-speed film processed with conventional chemistry and six of the rapid imaging systems studied. The percentage length of the file visible was significantly less for Sens-A-Ray (P=0.02) and for Nix NF45-100 film (P<0.005)when compared with D-speed film processed with conventional chemistry. This difference in file length is probably not of clinical importance for the Sens-A-Ray images but may be so for the Nix images.