## 1 Introduction  
Affecting 1 in every 800 live births globally [1], cleft lip and palate represent the most prevalent craniofacial birth defects. The aim of the surgical hard and soft tissue closure is to restore the complete function of the stomatognathic system, ensuring that speech, chewing, and breathing are adequately supported [2]. However, preoperative infant orthopedic interventions precede surgical cleft closure, beginning at birth and presenting unique challenges. Shortly after birth, a removable drinking plate is custom fabricated for each patient. This obturator not only separates the oral and nasal cavities, functioning as an artificial palatal roof to establish a physiological anterior caudal tongue position, but also enhances sucking and swallowing functions [3]. Within the framework of Presurgical Infant Orthopedics (PSIO), 3D models of the patient's upper jaw are digitally modified through incremental modification of the cleft region based on empirical judgment, aiming to align and harmonize the upper jaw segments toward a physiological arch form in preparation for surgical cleft closure. This demands not only professional expertise but also, most importantly, a profound comprehension of the maxillary growth patterns by the practitioner. Most previous studies have investigated morphological changes in the maxilla based on measurements taken from plaster casts [4; 5; 6; 7] or digitized plaster models [8; 9; 10; 11; 12; 13]. Traditional impression taking with alginate carries several risks. The complex anatomy of the cleft area increases the likelihood of the impression material tearing during the process. Impression material left unnoticed in the cleft area can cause inflammation in the surrounding tissues. In severe cases, torn impression material may lead to aspiration, necessitating immediate medical intervention [14]. The mentioned risks associated with conventional impressions (CI) may be one reason why previous measuring studies based on plaster models have only produced models at a few points in time; therefore, the observation periods are very wide. If an alginate impression is poured incorrectly and contains bubbles or if the plaster used for the die material is either too thick or too thin, dimensional inaccuracies can occur. Furthermore, being brittle and bulky, the storage and retrieval of plaster casts is challenging [15]. As advancements in digital technologies continue to reshape healthcare, the integration of digital impression methods with intraoral 3D scanners offers significant advantages. Digital impressions (intraoral 3D scan; IOS) for newborn infants with unilateral cleft lip and palate are safe, effective, and cost-efficient. Compared to conventional impression methods, they are not associated with serious risks. It is possible in rare cases for a patient to bite the tip of the intraoral 3D scanner during IOS, causing a slight superficial irritation of the mucosa, which will heal itself without medical intervention [16]. Unlike conventional impressions, there is no comparable risk of material tearing. This makes repeated use possible throughout the course of therapy for reevaluation or therapy planning. Additionally, this new, risk-free impression-taking capability allows for rescanning of anatomically challenging areas that may not be optimally represented or are difficult to access due to cleft-related issues, ensuring the highest quality of digital maxillary models [17]. The IOS offers accuracy comparable to that of conventional alginate impressions [17]. It minimizes material-related errors commonly associated with traditional alginate methods [15]. Since there is no need to customize and adapt an individual impression tray, IOS proves to be a time- and cost-efficient approach. With the appropriate expertise, an IOS can be completed within minutes, providing high-quality images of the individual jaw segment structures. IOS digital data can be easily stored, shared, and accessed, enhancing communication between clinicians and specialized healthcare centers.