Incorrect horizontal angulation leads to which type of error?

Incorrect horizontal angulation results in horizontal overlapping of structures on radiographs. When the X-ray beam is not aligned properly in the horizontal direction, it can cause adjacent teeth to project onto one another, making it challenging to distinguish individual structures. This overlap can obscure important diagnostic information, leading to potential missed caries or other dental issues. Proper horizontal angulation is crucial for ensuring clear and accurate images, allowing for a more effective evaluation of dental health.