Content Analysis of YouTube Videos That Demonstrate Periapical Radiography

Abstract

No prior study has evaluated the content of YouTube videos that demonstrated how to take periapical radiographs, one of the commonest radiographic examinations in dentistry. This study provided a content analysis on these YouTube videos. Three separate searches were performed with the following search strings: (1) posterior periapical, (2) molar periapical, and (3) anterior periapical. The videos resulting from the searches were sorted by view count, and their related videos (as listed by YouTube on the right of the screen) were also screened. Exclusion criteria included irrelevance to periapical radiography, no real patient involved, no demonstration of periapical radiography procedures), non-English video, and duplicate videos. Finally, 21 videos were included and analyzed. For each included video, the following aspects were evaluated: general settings (types of image receptor, patient age, and radiographic technique), patient preparation, machine preparation, receptor placement, and operator safety. 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 not removing the metallic objects from the patient’s head and neck region, not showing the selection of radiation dose, not placing the orientation dot on the film or phosphor plate on the occlusal side, and not wearing proper personal protective equipment. More instructional videos are definitely required. Future videos should eliminate these issues, and also demonstrate with pediatric patients. Perhaps the dental radiology department of a well-established university should be enticed to produce an instructional video that presents the technique in a flawless presentation, to facilitate the learning of dental students, dental hygienists and dental assistants who have yet to master their skills.

1. Introduction

Periapical radiography is an essential part of radiographic examination in modern dentistry, as it allows dentists to evaluate the entire tooth of interest as well as its surrounding periapical structures such as the periodontal ligament space, lamina dura, and bone trabeculae in the alveolar bone. The clinical indications for periapical radiography included, but not limited to, assessment of periodontal status, tooth extraction, caries detection, root canal treatment evaluation, examination of periapical pathology, and postoperative assessment of implant insertion [1]. Ideally, tailor-made instructional videos should be produced by dental schools to complement on-site face-to-face tutor demonstrations, and to facilitate student learning and revision [2,3,4]. There are multiple online platforms that host healthcare educational materials including videos, such as Procedures Consult, MedClip, MedlinePlus, Medical Videos, MedEdPORTAL, and Health Education Assets Library [5,6]. However, YouTube remains one of the most popular and easily accessible platforms for students and clinicians to watch videos, including educational videos on endodontology and oral surgery [7,8,9]. A prior survey indicated that YouTube was the most commonly consulted source among students and clinicians for educational videos on anatomy [10] and surgery procedures [11]. It is well-understood that misinformation/inaccurate information may exist among materials posted on social media and online platforms [12,13]. Recent studies by our team have identified issues on the content accuracy of YouTube videos that demonstrate how to take panoramic radiographs and how to identify anatomical landmarks on panoramic radiographs [14,15]. These studies implied a need to evaluate the content of other YouTube videos on dental radiology. Since periapical radiography is one of the commonest radiographic examinations in dentistry, it is important to assess the content of the videos that demonstrate its procedures so that the dental schools can better understand the quality of them as potential learning resources for students. Hence, the aim of this study was to evaluate YouTube videos that demonstrated how to take periapical radiographs, to identify the correct procedures that could be followed and incorrect settings that should not be avoided.

2. Materials and Methods

A search for the targeted YouTube videos was conducted in July 2022. One author (A.Y.) performed pilot searches with two search strings: posterior periapical and anterior periapical. By examining several resultant videos and their related videos, the author found that molar periapical was another recurring phrase in the video titles. Hence, three formal separate searches were performed with the following search strings: (1) posterior periapical, (2) molar periapical, and (3) anterior periapical. The videos resulting from the searches were sorted by view count, and their related videos (as listed by YouTube on the right of the screen) were screened. Exclusion criteria consisted of irrelevance to periapical radiography, no real patient involved, no demonstration of periapical radiography procedures), non-English video, and duplicate videos. The entire video screening process is illustrated in Figure 1. Both authors (A.Y. and M.G.) performed these formal searches independently. Disagreements were resolved by discussion between the authors. Finally, 21 videos were included and analyzed. For each included video, the following aspects were evaluated: general settings (types of image receptor, patient, and radiographic technique), patient preparation, machine preparation, receptor placement, and operator safety. Thirty items related to the video content were defined, and each video was coded accordingly (Supplementary Table S1).

The number of views, likes, comments, channel subscribers were recorded, as well as the video duration and age of the video. Data extraction and coding were performed by one author (M.G.) and verified by another author (A.Y.). Disagreements were again resolved by discussion between the authors. Pearson correlation tests were conducted to evaluate if any of these performance metrics were significantly correlated. A test was considered significant if p < 0.05.

Ethical approval was not applicable to this study.

3. Results

The web links and coded data extracted from the 21 videos on demonstration of periapical radiography are listed in Supplementary Table S1. The oldest one was uploaded on 2 July 2009 and its caption stated that the original air date of that recorded video was actually 2 August 1972 (https://www.youtube.com/watch?v=TQZQCywto38 (accessed on 26 July 2022)). Meanwhile, the most recent one was uploaded on 6/5/2021. Year 2016 had the highest number of videos uploaded (n = 6). There was no obvious trend in the number of videos uploaded against year, though it seemed that most of them have been uploaded to YouTube since 2015 (Figure 2). Nine of the videos were uploaded by dental school channels, 7 by individual key opinion leaders (KOLs) such as dentists or dental hygienists, and 5 by dental suppliers.

The majority of the videos (71.4%) demonstrated periapical radiography with digital imaging (10 of them using intraoral sensor, 5 using phosphor plate), while the remaining 28.6% of the videos used traditional films. All but one video involved an adult patient. Child patient was involved in one video only. About 90.5% of the videos (n = 19) demonstrated paralleling technique, whereas 9.5% (n = 2) of them demonstrated bisecting angle technique. For patient preparation, less than a quarter of the videos (23.8%) explicitly asked the patient to remove (or showed the actual removal of) metallic objects from the patient’s head and neck region (

Table 1. The frequency counts of (A) patient preparation, and (B) machine preparation procedures.

	No. of Videos	% (of 21)
(A) Patient preparation
(1) Remove metallic objects from head and neck region
Yes	5	23.8
No	16	76.2
(2) Explain procedures to the patient
Yes	17	81.0
No	4	19.0
(3) Patient wearing lead apron
Yes	7	33.3
No	13	61.9
Cannot be determined	1	4.8
(4) Patient wearing thyroid collar
Yes	15	71.4
No	6	28.6
(B) Machine preparation
(1) Choose correct radiation dose (e.g., body size, tooth type)
Yes	6	28.6
No	15	71.4
(2) Collimator type
Circular	8	38.1
Rectangular	11	52.4
Pointed	1	4.8
Not shown	1	4.8

). Meanwhile, 81.0% of the videos explained procedures to the patient. Lead apron and thyroid collar were worn by patients in 33.3% and 71.4% of the videos, respectively. For machine preparation, only 28.6% of the videos showed the selection of correct radiation dose (e.g., according to body size, and tooth type), and 52.4% of them used a rectangular collimator.

For receptor placement procedures, most of the videos (85.7%) showed to the audience which side of the receptor should face the X-ray beam (

Table 2. The frequency counts of receptor placement procedures.

	No. of Videos	% (of 21)
(1) Show which side of the receptor should facing the X-ray beam
Yes	18	85.7
No	3	14.3
(2) Receptor covered by plastic barrier for infection control
Yes	15	71.4
No	6	28.6
(3) Show that the orientation dot should be placed on the occlusal side
Yes	3	14.3
No	9	42.9
Not applicable (e.g., for intraoral sensor)	9	42.9
(4) Use receptor holder
Yes	19	90.5
No	2	9.5
(5) Correct assembly of receptor holder
Yes	19	90.5
No	0	0
Not applicable	2	9.5
(6) Place cotton roll
On the opposing tooth (or opposing side of the biteblock)	5	23.8
On the target tooth (or the side of the biteblock bitten by target tooth)	1	4.8
No usage	15	71.4
(7) Push the holder’s aiming ring close to patient’s face
Yes	16	76.2
No	3	14.3
Not applicable	2	9.5
(8) Show that the collimator is parallel to the holder vertically
Yes	19	90.5
No	0	0
Not applicable	2	9.5
(9) Show that the collimator is parallel to the holder horizontally
Yes	19	90.5
No	0	0
Not applicable	2	9.5
(10) Show that patient has a stable bite on the biteblock
Yes	18	85.7
No	2	9.5
Not applicable	1	4.8
(11) Show that the receptor is straight but not bent
Yes	19	90.5
No	0	0
Cannot be determined	2	9.5
(12) For maxillary posterior, receptor placed at		(% of 9)
Midline of the palate	7	77.8
Ipsilateral side of the palate	1	11.1
Contralateral side of the palate	1	11.1
(13) For mandibular posterior, receptor placed at		(% of 8)
Tongue surface	3	37.5
Lingual sulcus of the ipsilateral side	5	62.5
Lingual sulcus of the contralateral side	0	0
(14) For maxillary anterior, receptor placed at		(% of 7)
Centre of the palate	7	100
Cannot be determined	0	0
(15) For mandibular anterior, receptor placed at		(% of 5)
Tongue surface	1	20.0
Lingual sulcus	4	80.0

). Meanwhile, all videos using digital imaging covered their receptor with a plastic barrier for infection control. All 6 videos using traditional films showed the film packet being inserted into the patient’s mouth directly, with none of them using ClinAsept (or equivalent)—a plastic barrier that additionally covers the film packet. Only 3 videos (14.3%) demonstrated that the orientation dot should be placed on the occlusal side. Two videos did not use a receptor holder, and they were both demonstrating the bisecting angle technique. For the 19 videos using a receptor holder and demonstrating the paralleling technique, all of them assembled the holder correctly. However, it should be noted that for one video that demonstrated mandibular posterior periapicals, in one scene the aiming ring was actually covering the maxillary posterior region (https://www.youtube.com/watch?v=4k3RR6VxxFk, the problematic scene began at 3:01 (accessed on 26 July 2022)). Most of the videos (71.4%) did not apply a cotton roll to facilitate the stable placement of the receptor holder. Five videos placed a cotton roll on the opposing teeth to help stabilize the biteblock. One video demonstrated putting a cotton roll on the incisal edge of the tooth to be radiographed, stating that this act could help “prevent cutting off the incisal edge of the tooth” on the resultant image. Most of the videos pushed the aiming ring close to the patient’s face, showed parallelism between the collimator and the receptor holder in both vertical and horizontal dimensions, kept the receptor unbent within the oral cavity, and showed the patient having a stable bite onto the biteblock. Two videos showed the patient with closed lips after biting the biteblock, so it was not possible to verify if the biteblock was held in the correct position by teeth or held by soft tissues in a potentially incorrect position.

Meanwhile, it should be noted that most videos showed the placement of the receptor at the midline of the palate when taking a maxillary posterior periapical (Table 2). For mandibular posterior periapicals, the demonstration was less consistent, as 5 of the 8 videos (62.5%) placed the receptor into the lingual sulcus, whereas 3 of them (37.5%) pressed the receptor against the tongue surface. For mandibular anterior periapicals, 4 of the 5 videos (80.0%) placed the receptor into the lingual sulcus, whereas one video (20.0%) placed it onto the tongue surface.

For operator safety procedures, only one of the videos (4.8%) clearly showed that the operator left the radiographic room and closed its door before pressing the exposure button (

Table 3. The frequency counts of operator safety procedures.

	No. of Videos	% (of 21)
(1) Operator position
Totally shielded with door closed	1	4.8
Shielded position with door opened (or no door)	7	33.3
Inside the room with lead apron	0	0
Totally unprotected	3	14.3
Cannot be determined	10	47.6
(2) Wearing head cap
Yes	0	0
No	17	81.0
Cannot be determined	4	19.0
(3) Wearing eye protection or face shield
Yes	4	19.0
No	13	61.9
Cannot be determined	4	19.0
(4) Wearing surgical mask
Yes	4	19.0
No	13	61.9
Cannot be determined	4	19.0
(5) Wearing gloves
Yes	20	95.2
No	1	4.8
(6) Body wear
Long sleeved disposable gown	2	9.5
Clinical uniform	14	66.7
Lab coat	3	14.3
Casual wear	0	0
Cannot be determined	2	9.5

). Nealy half of the videos (47.6%) did not have enough information on whether the door was closed during exposure. None of the videos showed an operator wearing a head cap. Eye protection or face shield was worn by the operator in 4 videos (19.0%). Even a surgical mask was only worn by the operator in 4 videos (19.0%). Most of the videos (95.2%) showed an operator wearing gloves. Two thirds of the videos (66.7%) had an operator wearing a clinical uniform.

Table 4. Viewing metrics of the 21 videos.

Metric	Mean ± SD	Min; Max
View count	59,392.1 ± 156,916.2	31; 715,373
Like count	382.0 ± 1085.2	0; 5000
Comment count	8.2 ± 23.2	0; 102
Channel subscriber count	18,993.8 ± 32,080.4	10; 109,000
Duration (s)	303.4 ± 532.3	63; 2581
Age of video (y)	5.4 ± 2.9	1.2; 13.1

lists a summary of the viewing metrics of the videos. Each video was viewed 59,392 times on average. The video with the highest view count among the 21 videos (https://www.youtube.com/watch?v=H0qZVv8It0E (accessed on 26 July 2022)) has accumulated over 0.7 million views. It demonstrates how to take maxillary and mandibular posterior periapicals with traditional film. On average, each video had 8 comments and 382 likes, and lasted for 5 min. One video disabled the comment function. View count was positively correlated with like count, comment count, and channel subscriber count (

Table 5. Pearson correlation between the viewing metrics.

	Like Count	Comment Count	Channel Subscriber Count	Duration (s)	Video Age (y)
View count	0.996 (p < 0.001)	0.989 (p < 0.001)	0.511 (p = 0.018)	0.165 (p = 0.475)	0.285 (p = 0.211)
Like count		0.991 (p < 0.001)	0.516 (p = 0.017)	0.138 (p = 0.552)	0.238 (p = 0.299)
Comment count			0.578 (p = 0.008)	0.242 (p = 0.303)	0.287 (p = 0.219)
Channel subscriber count				0.574 (p = 0.007)	0.360 (p = 0.109)
Duration (s)					0.575 (p = 0.006)

).

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. 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.

One of the few issues commonly identified from the videos was the omission of removing the metallic objects from the patient’s head and neck region. Straightly speaking, the metallic earrings or eyeglasses do not affect the image quality for many of the intraoral radiographs as they are often outside the field of view. However, they would become detrimental if the patient would subsequently take other radiographs such as occlusal or panoramic radiographs. Our prior study indeed found that some instructional videos on panoramic radiography showed metallic earrings on the resultant image, thus obscuring the region of interest [14]. Each clinic has its own standard operating procedure, but the authors perceived that it is a good practice to instruct patients to remove the metallic objects from the patient’s head and neck region on a routine basis before undergoing dental radiographic examinations. This routine practice is especially useful for junior students who may become unaware of the metallic objects during subsequent radiographic examinations.

Many of the surveyed videos focused on the assembly of the receptor holder and its positioning within the oral cavity, whereas omitting the scene or explanation on choosing a correct radiation dose according to patient’s body size and tooth type to be imaged. Optimized radiation dose may not be very critical with regards to image quality for clinics using phosphor plates, as they can still produce good quality radiographic images at exposure times lower or higher than the standard, rendering a much reduced chance of under- and over-exposure [17]. However, the principle of “as low as reasonably achievable” (ALARA) advocates against an unnecessary increase in the radiation dose [18]. The principle has now evolved into “as low as diagnostically achievable being indication-oriented and patient-specific” (ALADAIP), implying that correct setting of the radiation dose according with the aid of the body size and tooth type controls is of paramount importance especially for pediatric patients [19]. From the radioprotective perspective, the instructional videos should demonstrate the selection of proper radiation dose from the control panel.

Another common issue was not showing the orientation dot on the film or phosphor plate to be placed on the occlusal side. The original intention of the orientation dot is to indicate which side of a radiographic film is the surface during viewing. The physical dot should be raised on the surface side. One drawback of the dot is that its presence will obscure the image, and that is why it should be placed on the occlusal side, so that the periapical region including root apices and surrounding structures will be preserved. For intraoral sensors and phosphor plates, the issue of determining the surface during viewing is not applicable, as the digital images are viewed directly on the computer screen. If an operator wrongly flips or rotates a digital image on the computer screen, the digital orientation dot cannot provide any clues, unless the operator has made customized rules during radiographic taking (e.g., the dot should always be placed towards the mesial side); however, then it would have a chance to obscure the periapical region. The authors were unclear which digital imaging systems still incorporated the orientation dot or mark, but it should be placed on the occlusal side when present.

It is important to make the patient feel as comfortable as possible during periapical radiography. Besides the operator’s technique and experience, the design of the image receptor and the receptor holder would also affect the patient comfort level [20,21]. The intraoral sensor is rigid and bulky, whereas the traditional film packet and phosphor plate are thin but the edges are relatively sharp. The pressure exerted against the floor of the mouth or the lingual sulcus during taking mandibular periapicals may particularly cause discomfort to the patients. Due to this, soft foam attachments such as Edge-Ease (Strong Products, Corona, CA, USA) can be attached to the periphery of the receptor as cushions to make its corners and edges more rounded and comfortable to the patients. Alternatively, simply wrapping the receptor with a gauze may, to a lesser extent, serve the same purpose. However, none of the 21 analyzed videos showed the application of these attachments. Instead, several videos placed the receptor on the tongue surface when taking periapicals for the mandibular teeth to avoid hurting the lingual sulcus. It could be argued that a child patient might not be accustomed to (or even potentially reject) putting an object “underneath” his/her tongue. The only video with a child patient indeed placed the intraoral sensor onto the tongue. There were two other videos with an adult patient, one each with intraoral sensor and film. The former video instructed the patient to stick out her tongue and placed the intraoral sensor in the centre of her extended tongue (https://www.youtube.com/watch?v=nBrM_kNEPX0 (accessed on 26 July 2022)). The latter video placed the film in the centre of the patient’s tongue within the oral cavity and exerted pressure on the tongue to ensure it would not displace the film (https://www.youtube.com/watch?v=H0qZVv8It0E (accessed on 26 July 2022)). This was different from conventional instructions from oral and maxillofacial radiology textbooks, which instructed students to place the receptor into the lingual sulcus lingual to the teeth to be imaged. Without placing cushions, the receptor could actually be causing discomfort to the tongue surface. Besides, if the receptor could not be placed on posterior tongue surface to avoid triggering the gag reflex, then the resultant image might not cover the posterior teeth such as the second molar.

During the COVID-19 pandemic era, infection control should be heavily emphasized. The latest recommendation for the minimal PPE for dental radiology procedures should include head cap, goggles/face shield, surgical mask, gloves, and long-sleeved gown [22]. Surprisingly, the majority of the videos showed an operator without wearing a head cap, eye protection, or a mask. This alarming situation was comparable to the videos that demonstrated how to take panoramic radiographs [14]. Regardless of the rationales behind this lack of PPE, junior students may be misguided to think that it is the standard. The lack of a mask can be potentially harmful, as patients may cough during intraoral radiography, particularly for posterior periapicals that need to be positioned close to the throat or the back of the mouth. Hence, future videos produced should demonstrate proper usage of PPE. The oldest video, uploaded on 2/7/2009 but originally aired on 2 August 1972 (https://www.youtube.com/watch?v=TQZQCywto38 (accessed on 26 July 2022)), showed an operator even without wearing gloves. The infection control standard 50 years ago certainly is not comparable to the standard nowadays, but the video has accumulated 165,424 views since it was uploaded in 2009. The video did not have any disclaimer or notice to remind the audience about this infection control issue. Only one out of the 31 comments made by the audience pointed out the lack of hand gloves. This comment received one “like” and one reply that “gloves were not common practice nor required if you go back far enough”. This comment was not pinned or listed as top comments, so students might not easily recognize it.

This survey has several limitations. Only YouTube videos narrated in English were considered. The view and comment counts could not show the background of the audience, so it was not possible to know the how many of the viewers were students and how many were casual viewers. Moreover, the audience could always identify the channel (account) that uploaded the video, but the identity of the actual video producer could be different or unknown. Take a video (https://www.youtube.com/watch?v=ILYi7Ueo-Ro) (accessed on 31 July 2022) as an example. The channel that uploaded it provided no information in its “About” page, except that he was located in Turkey. However, the last scene of the video acknowledged “University of Toronto, Faculty of Dentistry”. There was no video description to explain his relationship with the University. In fact, if he cut the acknowledgement scene before upload, then the audience could never recognize who produced it. This is a point to be considered by students who search for videos for learning. Students can only identify the channel and rely on this to assess the credibility, but may be unable to identify the actual content producer. Videos showing demonstrations with a phantom head were excluded, because such videos could not demonstrate patient preparation properly, such as the removal of earrings, necklaces, and dentures. They also could not show delicate receptor placement procedures, as the receptor could be placed virtually anywhere within the mouth of the phantom head.

5. Conclusions

This YouTube video survey found that there was a lack of videos on periapical radiography demonstrated with pediatric patients. 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 regarding patient preparation, machine preparation, receptor placement, and operator safety. More instructional videos are definitely required. Future videos should eliminate these issues and also demonstrate with pediatric patients. Perhaps the dental radiology department of a well-established university should be enticed to produce an instructional video that presents the technique in a flawless presentation, to facilitate the learning of dental students, dental hygienists and dental assistants who have yet to master the skills.