A dental x-ray that has the appearance of black lines that look like a tree branch is caused by

• A. Static electricity
• B. Overexposure
• C. Underexposure
• D. Film fogging

Answer: (A)

Static electricity causes tree-branch–like dark lines on dental radiographs. A charge builds on the film and a discharge occurs during handling, especially in dry conditions, exposing the film along irregular branching paths and creating the black, branching patterns seen. To prevent this, keep humidity at a moderate level, handle film by the edges, and use anti-static precautions. Overexposure would darken the entire image, underexposure would lighten it overall, and film fogging would cause a general loss of detail rather than discrete branching lines.