What is the effect of using a high kilovoltage peak (>90kVp) in dental radiography?

Using a high kilovoltage peak (kVp) of greater than 90 in dental radiography results in low subject contrast and presents many shades of gray in the resultant images. This outcome occurs because higher kVp settings increase the energy of the X-rays produced.

When X-rays have higher energy, they penetrate tissues more effectively, resulting in less differential absorption between various structures. As a consequence, rather than having stark contrasts between light and dark areas—characteristic of high contrast images—there is a smoother transition between shades, yielding a wider range of grays. This is particularly useful in diagnostic radiography, as it can enhance the visualization of subtle differences in tissue densities, helping to detect pathology that might not be evident with high contrast techniques, where only areas of black and white are prominent.

On the other hand, low kVp settings generate images with higher contrast, highlighting differences between varying densities. It is essential to understand the impact of kilovoltage settings on image quality, as they directly influence the interpretability and diagnostic value of radiographic images.