1 Department of Oral Diagnosis, Division of Oral Radiology,, Piracicaba Dental School, University of Campinas (UNICAMP) , Sao Paulo , Brazil.
Dentomaxillofac Radiol. 2019 Mar;48(3):20180331. doi: 10.1259/dmfr.20180331. Epub 2019 Jan 3.
: To investigate the influence of high-density dental material on the automatic exposure compensation of digital radiographic imaging systems.
: Two radiographic phantoms were custom made to reproduce radiographic densities of the dental tissues: enamel, dentin and pulp chamber. The phantoms were X-rayed using the Digora Toto, Digora Optime and VistaScan systems for 0.063, 0.1 and 0.16 s. Radiographic acquisitions were repeated in the presence of a high-density material equivalent to a titanium implant, in the small and large sizes. Mean grey values of the dental tissue-equivalent regions were obtained with the Image J software, averaged and compared between the absence and presence of the high-density material using ANOVA for multiple comparisons and Tukey's test (α = 0.05).
: The presence of a high-density material significantly (p ≤ 0.05) decreased grey values of the dental tissue-equivalent images in the Digora Toto and VistaScan, regardless of the exposure time. For the Digora Optime, the high-density material decreased the pulp-equivalent grey values at all exposure times, the dentin-equivalent grey values significantly increased at exposure time of the 0.1 and 0.16 s, and the enamel-equivalent grey values significantly increased at the exposure time of 0.16 s (p ≤ 0.05). In general, the size of the high-density material did not affect the grey values significantly (p ≤ 0.05).
: In general, the presence of a high-density dental material in digital radiographic systems influences the AEC by adjusting dental tissue-equivalent grey values.
研究高密度牙科材料对数字射线照相成像系统自动曝光补偿的影响。
定制了两个射线照相体模，以再现牙齿组织的射线照相密度：釉质、牙本质和牙髓腔。使用 Digora Toto、Digora Optime 和 VistaScan 系统分别对 0.063、0.1 和 0.16 秒的小和大尺寸的射线照相体模进行 X 射线照射。在存在相当于钛种植体的高密度材料的情况下重复进行射线照相采集。使用 Image J 软件获得牙齿组织等效区域的平均灰度值，使用方差分析和 Tukey 检验（α=0.05）对有无高密度材料的情况下的平均灰度值进行比较。
无论曝光时间如何，高密度材料的存在都会显著降低 Digora Toto 和 VistaScan 中牙齿组织等效图像的灰度值（p ≤ 0.05）。对于 Digora Optime，高密度材料会降低所有曝光时间的牙髓等效灰度值，在 0.1 和 0.16 秒的曝光时间下，牙本质等效灰度值显著增加，在 0.16 秒的曝光时间下，釉质等效灰度值显著增加（p ≤ 0.05）。一般来说，高密度材料的尺寸不会显著影响灰度值（p ≤ 0.05）。
一般来说，高密度牙科材料的存在会通过调整牙齿组织等效灰度值来影响 AEC。
