## 4 Discussion
The explanation could be that clinicians specialized in sleep medicine are inclined to bring their experience and knowledge online in order to allow easy access to information for people looking for professional opinions. The finding that commercial companies were also well-represented in our research (22%) might be due to the increasing interest of modern manufacturing houses in social media management and advertiezment engagement. In our sample, the target audience was laypeople in 71% of videos, in agreement with the current literature [16; 21; 36]. If we assume that common people regard the Internet as a preferential route of information, it can be interpreted positively because common users could obviously better understand easy and plain language and concepts. The VIQI revealed that the overall quality, precision and educational content provided by specialists was higher (although considered overall moderate) compared with those provided by common people. The finding that dental manufacturing companies also showed moderate scores means that the commercial industry is investing in communication and valuable advertiezment. Regarding m-DISCERN, videos uploaded by laypeople and commercial companies had significantly lower scores compared to videos by healthcare professionals and by hospitals/universities (considered moderate). In detail, the scores obtained by laypeople and commercial companies were classified as poor, in accordance with [PERSON] et al. [27]. This finding is consistent with the current literature and may reflect that the information used by hospitals/universities and health professionals is from more reputable sources and is therefore presented in a clear and unbiased manner [40]. As for JAMA, all categories of uploaders reached mean values of 2, reflecting a lack of accurate and reliable information provided. As for the content analysis, videos uploaded by healthcare professionals and hospitals/universities were considered \"useful\" according to the scoring scheme adopted in the present study, while commercial and laypeople videos showed \"moderately useful\" scores. In general, these values, failing to exceed the cut-off of 3.00, detected a low level of educational content. In detail, it is noteworthy that no video mentioned all the topics of the customized checklist adopted in the present study. In accordance with the current evidence from the available literature, many videos answered only one or two of the analyzed criteria [16; 21]. The most quoted topics in the videos were the definition and indication of MAD, which was clearly the underlying and implied information to start a video dealing with that topic. Less than half of the videos mentioned an alternative treatment like CPAP or surgery, and no information was provided in order to make the viewer educated on the pros and cons of them. The instructions on the usage of MAD were provided in 20% of videos, consisting of wearing the appliance during the night. Only 17% of the videos mentioned short- or long-term side effects like hypersalivation, xerostomia, tooth discomfort, muscular pain or temporomandibular disorders (TMDs) and occlusal changes [41; 42; 43; 44]. As for short-term effects, they are temporary and are going to vanish in days or months. Long-term adverse effects must be clearly explained to patients in order to secure their compliance during treatment. The duration of treatment with MAD is likely to be life-long, and in our study, this aspect proved to be stressed only in 9.5% of videos. We think such a lack of information can be really misleading for patients, who often expect fast and decisive therapy. Another topic that was mentioned only in 9.5% of the videos regards contraindications that should be considered by dentists when proposing MAD for the treatment of OSA. An insufficient number of teeth or general precarious oral health (inadequate prosthetics or restorations, periodontal disease), the presence of active TMDs and a reduction in mandibular protrusion ability are conditions that can impede the usage of MAD [44; 45].