# Content Analysis of YouTube Videos That Demonstrate Periapical Radiography
## 4 Discussion  
This study identified 21 YouTube videos that demonstrated how to take dental periapical radiographs for real patients. All but one were demonstrated with an adult patient. The videos were largely based on digital imaging with the use of either intraoral sensors or phosphor plates, and mostly used paralleling technique. Several common issues were identified, such as (1) the omission of removing the metallic objects from the patient's head and neck region, (2) not showing the selection of correct radiation dose according to patient's body size and tooth type to be imaged, (3) not showing the orientation dot on the film or phosphor plate to be placed on the occlusal side, and (4) the operator not wearing proper personal protective equipment (PPE). Many undergraduates in healthcare programs perceived YouTube videos on clinical procedures as very helpful for their learning, and many of them actually referred to a YouTube video to prepare themselves for clinical procedures never attempted beforehand [16]. Taking a periapical radiograph for a dental patient is particularly different from taking a medical radiograph such as a chest X-ray, because it requires the operator to place the image receptor into the patient's body (oral cavity), within which the soft tissues may push the receptor away from the desired position. Besides pain induced by soft tissue impingement, the soft palate and the posterior tongue can be sensitive and pressing against them may trigger gag reflex. Therefore, it is important for the operator to try his/her best to obtain a diagnostically acceptable periapical image in the first attempt, as patient's tolerance to pain and gagging may reduce in subsequent attempts. Undoubtedly, each clinic has its own established standard operating procedure. For instance, there may be differences in the brand/model of the dental chair, radiographic machine, image receptor and its holder. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Metric** & **Mean \(\pm\) SD** & **Min; Max** \\ \hline View count & 59,392.1 \(\pm\) 156,916.2 & 31; 715,373 \\ \hline Like count & 382.0 \(\pm\) 1085.2 & 0; 5000 \\ \hline Comment count & 8.2 \(\pm\) 23.2 & 0; 102 \\ \hline Channel subscriber count & 18,993.8 \(\pm\) 32,080.4 & 10; 109,000 \\ \hline Duration (s) & 303.4 \(\pm\) 532.3 & 63; 2581 \\ \hline Age of video (y) & 5.4 \(\pm\) 2.9 & 1.2; 13.1 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Viewing metrics of the 21 videos. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & **Like Count** & **Comment Count** & **Channel Subscriber Count** & **Duration (s)** & **Video Age (y)** \\ \hline View count & \begin{tabular}{c} 0.996 \\ (\(p<0.001\)) \\ \end{tabular} & \begin{tabular}{c} 0.989 \\ (\(p<0.001\)) \\ \end{tabular} & \begin{tabular}{c} 0.511 \\ (\(p=0.018\)) \\ \end{tabular} & \begin{tabular}{c} 0.165 \\ (\(p=0.475\)) \\ \end{tabular} & \begin{tabular}{c} 0.285 \\ (\(p=0.211\)) \\ \end{tabular} \\ \hline Like count & \begin{tabular}{c} 0.991 \\ (\(p<0.001\)) \\ \end{tabular} & \begin{tabular}{c} 0.516 \\ (\(p=0.017\)) \\ \end{tabular} & \begin{tabular}{c} 0.138 \\ (\(p=0.552\)) \\ \end{tabular} & \begin{tabular}{c} 0.238 \\ (\(p=0.299\)) \\ \end{tabular} \\ \hline Comment count & & \begin{tabular}{c} 0.578 \\ (\(p=0.008\)) \\ \end{tabular} & \
\begin{tabular}{c} 0.242 \\ (\(p=0.303\)) \\ \end{tabular} &
\begin{tabular}{c} 0.287 \\ (\(p=0.219\)) \\ \end{tabular} \\ \hline Channel subscriber count & & & & 0.574 \\ \hline Duration (s) & & & & (\(p=0.007\)) \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Pearson correlation between the viewing metrics. Ideally, students should watch an instructional video that matches the settings from their clinical training. However, given that there were only 21 videos identified, it was highly unlikely for most students to find an ideal video for their learning purposes. Still, it was crucial to evaluate and ensure the major points or important procedures were demonstrated properly in these videos, so that they were useful for students.