Digital evaluation of the influence of interruption of the fixation process on radiographic contrast and base-plus-fog density in three commercial brands of radiographic films

INTRODUCTION : With the interest in anticipating access to the result of intraoral radiography, the radiographic processing is frequently neglected, compromising image quality. OBJECTIVE : The aim of this study was to evaluate the influence of interrupting the fixation process on the radiographic contrast and base-plus-fog density (BPFD) in three brands of periapical films. MATERIAL AND METHOD : Ninety radiographs were taken of an aluminum stepwedge and a lead plate for each brand, and they were divided according to the time of initial immersion in the fixative in: control group (without interrupting the fixing), 5, 10, 20, 30 and 40 seconds. During processing, films had the fixing stage stopped and were exposed to a negatoscope for 1 minute, then the fixation time of 10 minutes was completed. The radiographs were digitized and exported to Image Tool 3.0.software. RESULT : Kodak(r) film showed no statistically significant differences between groups, while Agfa(r) film presented difference in BPFD compared with Group 5 seconds, and Dentix(r) film showed statistical difference in all groups in comparison with the control group. CONCLUSION : Under the conditions studied, Kodak(r) film is not influenced by disruption of fixation as regards BPFD and image contrast, enabling early access to the results of radiographs, whereas Agfa(r) film requires at least 10 seconds of initial fixation, and Dentix(r) film obtains better results when the process of fixation is not interrupted.引言：鉴于临床对提前获取口内放射摄影结果的需求，放射影像冲洗流程常被忽视，进而降低影像质量。 目的：本研究旨在评估中断定影流程对三种品牌根尖片的放射影像对比度及基片灰雾密度（base-plus-fog density, BPFD）的影响。 材料与方法：针对每种品牌的胶片，使用铝阶梯楔块与铅板拍摄90张放射影像，并根据初次浸入定影液的时长分为以下组别：对照组（不中断定影过程）、5秒组、10秒组、20秒组、30秒组及40秒组。冲洗过程中，暂停定影阶段并将胶片置于观片灯下曝光1分钟，随后补足至总定影时长10分钟。将放射影像数字化后导出至Image Tool 3.0软件进行分析。 结果：柯达（Kodak(r)）胶片的各组间未出现统计学显著性差异；爱克发（Agfa(r)）胶片的基片灰雾密度在与5秒组的对比中存在差异；而登士柏（Dentix(r)）胶片的所有组别与对照组相比均存在统计学显著性差异。 结论：在本研究的实验条件下，柯达（Kodak(r)）胶片的基片灰雾密度与影像对比度不受定影中断的影响，可实现放射影像结果的提前获取；爱克发（Agfa(r)）胶片至少需要10秒的初次定影时长；而登士柏（Dentix(r)）胶片在不中断定影流程时可获得更优的影像结果。