According to the results of the thematic analysis, among the four categories of teledentistry; unique teledentistry systems and social networks have been reported by studies more often than others. As for unique teledentistry systems, one of the reasons for their application is customization, which means development based on the needs and objectives of the users. For instance, most studies have used such a system for a variety of purposes, including oral cancer screening [11, 15, 45, 49], remote diagnosis [46, 51], teleconsultation [14, 44, 48, 52], tele-education [47), and obtaining a second oral medicine opinion [43]. In addition, the increased use of social networks as a platform for teledentistry could be attributed to the new coronavirus [17, 38, 40]. During the COVID-19 pandemic, when the world faced a health crisis, there was no access to in-person oral medicine services [4, 17]. Social networks have therefore been used as an affordable and easily accessible platform for the general public and healthcare providers to continue providing care for patients [8, 24, 38], especially for those suffering from urgent and chronic diseases [7, 9]. Furthermore, using social networks is an emergency alternative for unique teledentistry systems in countries without such systems.

In contrast, the telephone was the least used platform for teledentistry [33, 34]. Owing to the significance of lesion observation and intraoral examination in patient evaluation within oral medicine [58], applying a phone call as a teledentistry platform poses limitations. Specialists cannot access videos and photos of the patient's oral lesions due to restrictions in the phone infrastructure, resulting in a decrease in diagnostic accuracy. Using the phone with other platforms could be more effective and improve the accurate diagnosis of oral lesions and other disorders.

The type of interactions have been categorized into three categories: store and forward, real-time, and both. Most studies have reported store and forward communication [11, 14, 15, 19, 29,30,31,32, 35, 38, 39, 41, 49, 52, 54]. This may be explained by technical issues related to internet connections in remote and underserved areas, leading to less real-time interaction use [11, 19, 59]. In addition, store and forward communication has several advantages over real-time interactions; most importantly, there is no need for the patient and the consultant to overlap over time and space, and it also makes it possible to assess a larger number of patients per session [6]. However, the evidence shows advantages to using both types, so using them together can be more efficient [2, 6, 10]. Many studies combined both communication methods [16, 24, 40, 43, 45,46,47,48, 50, 51, 53]. For example, remote visits [24,40) and remote triage [53] were conducted with this approach. Initially, videoconferencing was utilized for patient evaluation, followed by store and forward communication to determine the final diagnosis and treatment plan. Making accurate decisions depends on sending the patient’s clinical documents, such as intra-oral photography, X-ray image, and pathology report to the specialists [11, 29, 33].

According to the results of this study, teledentistry in oral medicine utilizes oral photography tools that fall under four main categories: mobile phone cameras, digital cameras, and intraoral cameras. Most studies have pointed to the use of mobile phone cameras. It is clear that mobile phones have a high penetration rate and ease of use and are available for patients and health care providers [29, 54, 60]. In addition, smartphones with high-quality cameras can deliver high-quality photos that increase diagnostic accuracy without using digital or intra-oral cameras, which are more expensive than mobile phones [8, 15, 54]. Consequently, many dental clinics, particularly small and remote clinics, use mobile phone cameras, as they need help to afford the costlier digital and intraoral cameras [13).

The results of this study showed that seven factors categorize photography recommendations. Most of the studies have concentrated on light [12, 13, 15, 51], photo-sending requirements [13, 30,31,32, 42, 51, 54], and photo visualization [29, 30, 32, 41, 42, 54]. In terms of light, several studies have suggested the importance of avoiding both overexposed and underexposed conditions [12, 15, 51]. These recommendations hold significance as the quality of the pictures submitted greatly influences the remote management of oral medicine conditions by specialists in this field [7, 40]. Also, accurate decision-making on final diagnosis is an important component of teledentistry. Therefore, high-quality photography is essential in improving the reliability of diagnosing oral lesions using teledentistry [15]. In this regard, several studies have highlighted the provision of a training guide to take photographs of the oral cavity for both healthcare workers and patients before using teledentistry [13, 15]. Another reason for providing photography recommendations of the oral cavity in teledentistry in the field of oral medicine is the importance and emphasis on obtaining high-quality images for various applications of teledentistry in the field of oral medicine, including tele-consultation [36, 38, 42, 48], tele-diagnosis [29, 31, 51], and tele-screening [11, 45, 54]. Photography is also important to document visual changes over time and facilitate collaboration across disciplines [13].

In terms of security services, the system offers them to safeguard the resources within the system [61]. With the increased use of teledentistry services in the field of oral medicine, particularly during the COVID-19 pandemic [17, 24, 29, 36,37,38, 40, 44, 56], to protect teledentistry platforms such as e-mail, social media, unique teledentistry systems, and phones from security threats, the adoption of these security services is critical to the application of teledentistry [16, 22]. According to the present thematic results, security services are classified into seven main themes: confidentiality, authentication, privacy, integrity, access control, availability, and device and media security controls. In this respect, many studies have focused on data confidentiality [8, 16, 29,30,31, 54], authentication services [16, 17, 19,