Which of the following may cause unnecessary radiation exposure to the patient?

Radiograph technique errors can lead to unnecessary radiation exposure for patients because improper technique may result in underexposed or overexposed images. For example, if a radiograph is not properly aligned or if the exposure time is incorrect, additional radiographs may need to be taken to obtain clear images for diagnostic purposes. This not only increases the overall radiation dose a patient receives but can also lead to complications such as repeat procedures that further expose patients to radiation.

In contrast, endodontic radiographs and standard radiographs taken during exam or recall appointments are performed based on clinical necessity. Such imaging is typically justified as it aids in diagnosis and treatment planning, ensuring that patients receive appropriate care without unnecessary exposure when done correctly.