## 1 Introduction  
One of the primary goals of dental treatment is to restore teeth in a way that meets the patient's needs and creates a natural-looking, esthetically pleasing smile [1]. Owing to technological advancements, esthetic dental materials and treatments are becoming more widely available [2]. The use of three-dimensional (3D) design technology to create personalized, natural-looking, and esthetically pleasing smiles is becoming increasingly popular in dental practices, and \"Digital smile design\" (DSD) programs are a key tool in this process. These programs allow the dentist and patient to plan treatment and provide a high level of convenience [3,4]. There are many DSD programs available on the market, and a common feature of all of them is that they evaluate the smile in the context of the entire face [5]. This requires a photograph in which the patient is naturally smiling [6, 7, 8]. The use of computer technology for the esthetic prosthetic treatment of patients is becoming increasingly common. Studies have shown that digitally-made designs are effective in meeting patients' esthetic expectations and achieving a predictable, satisfactory treatment outcome [5; 9]. One of the first studies to introduce digital smile analysis and design was conducted in 2002 [10]. Initially, programs such as PowerPoint, Keynote, and Photoshop were used for planning smile designs [5]. In the past, clinicians and technicians would perform esthetic analysis on printed photographs or plaster models obtained prior to treatment. These programs allow for the creation of esthetic reference lines on faces and smile photographs on the computer [4]. In 2008, the first DSD protocol was developed, which associated a series of facial, intraoral, and extraoral photographs with the face [11]. This allowed for a fully digital format transition, enabling the matching of 2D photographs with 3D digital models and the verification and improvement of 3D esthetic parameters [3; 11; 12; 13]. Computer programs and software tools help with the planning, execution, and visualization of restorative, prosthetic, orthodontic, surgical, and multidisciplinary treatments, while enabling the digital planning and visualization of expected esthetic results before treatment [14]. With the increased use of DSD programs in clinical settings, many innovations have been made to make these programs more accessible and practical. One such innovation is the integration of artificial intelligence into the software [15]. The term \"AI\" originated in the 1950s and referred to the idea that machines can perform tasks that humans typically perform [16]. In the future, AI is expected to automate esthetic evaluation, smile design, and treatment planning processes [2; 17; 18]. One of the main claims of companies is that smile designs created by AI can be produced in a short period of time (seconds), compared to those traditionally created by physicians [15; 18]. A key point in designing natural and harmonious smiles is that faces and smiles are not always symmetrical [19]. Various studies have shown a positive relationship between facial symmetry and beauty [20; 21]. Facial Flow (FF) is defined as \"the direction in which facial structures travel.\" The Facial Flow Line (FFL) can usually be towards the left or right side of the patient's face. FF is also defined as neutral in cases where the nose and chin tip go in opposite directions of the face, or in cases where the face is symmetrical [19]. Anatomical landmarks on symmetrical faces can be manually determined and used as reference points [20; 22; 23; 24]. However, more research needs to be conducted on whether these landmarks, which are crucial in creating smile designs, can be detected on asymmetrical faces using AI. It is noted that the application of AI in healthcare is still immature and requires significant improvement [25]. AI works according to a specific algorithm, and misinterpretations can occur due to the limitations of those algorithms [26].