Table 2.

Question content and question focus used in the quiz of the online course of dental radiation technology for dentist continuing education (DCE) offered by the Taiwan Dental Association (TWDA) in October 2022 and in March 2023 and the quiz results.

Question content (multiple choice)	Number (proportion) of dentists who answered this question correctly		Question focus Correct answer
	October 2022	March 2023
1. Which of the following can reduce the effect of image magnification? A. To use a short cone B. To use a long cone C. To reduce the focal spot to skin distance D. To increase the receptor to object distance	121/132 (91.67%)	102/117 (87.18%)	Radiographic principle B
2. Which of the following are the functions of the identification dot (or the English letter) on the radiographic film? When irradiating, the dot ①towards the X-ray tube ②back to the X-ray tube ③close to the occlusal surface ④away from the occlusal surface A. ①③ B. ①④ C. ②③ D. ②④	122/132 (92.42%)	110/117 (94.02%)	Radiographic principle A
3. Which of the following is the most ideal dental radiographic technique to avoid the shadowing of zygomatic bone when observing the apical lesion of the maxillary molars? A. Bisecting angle technique B. Bite-wing film technique C. Paralleling technique D. Occlusal film technique	119/132 (90.15%)	103/117 (88.03%)	Radiographic technique C
4. Which one is wrong in the description of panoramic radiography? A. The patient's Frankfort horizontal plane is parallel to the ground B. The upper and lower incisors of patient bite in the groove of machine C. To fix the head with a head clip to prevent the patient from shaking during irradiating D. To put the thyroid collar on the patient	126/132 (95.45%)	107/117 (91.45%)	Radiographic technique D
5. What kind of distorted image will be caused if the patient's head is raised too high during the positioning of panoramic radiography? A. The occlusal plane presents an inverted V shape, and the hard palate overlaps with the root apex of upper teeth B. Excessive magnification in the horizontal direction of lower incisors C. The image of anterior teeth is narrow and unclear D. The anatomical structure in the image is wide on one side and narrow on the other	111/132 (84.09%)	101/117 (86.32%)	Comprehensive concept A
Overall test results	Mean score ± SD		Significance
	October 2022	March 2023	t-test
Mean number of correct answers for all participants	4.54 ± 0.72	4.47 ± 0.80	P = 0.242