## 1 Introduction  
Endodontic treatment aims primarily to preserve fully functional natural teeth, providing patients with long-term oral health and comfort. However, literature shows lower success rates in cases of retreatment [1]. In these cases, in addition to microbiological complications, technical mistakes from the previous treatment may be found, such as obstructions, morphological alterations, apical transportation, and stripping. Given the various problems that may arise, dental implants are often preferred as a plausible and simplified alternative to retreatment [2]. Therefore, we have witnessed an increase in the number of implants as a replacement for teeth with apical periodontitis--without even considering more conservative alternatives [2]. Tenth with compromised coronal structures that require endodontic retreatment may need intraradicular posts to support coronal restorations. Although intraradicular posts are commonly used, catastrophic failures requiring tooth extraction have been reported [3]. Root fractures are a recognized risk of endodontic therapy, with studies identifying them as the most common cause of tooth extraction following endodontic retreatment with the removal of intraradicular posts [4]. It is important to note that endodontic retreatment can further weaken the tooth structure and increase the risk of root fractures [4]. Over time, the types of posts used in dentistry have evolved. Initially, intraradicular posts were realized in stainless steel or carbon fiber, but nowadays fiberglass posts are the most widely used [5]. However, studies show no significant difference in the incidence of root fractures between metal and fiber posts [6, 7]. Endodontically treated teeth may lose resistance due to the high loss of dental hard tissue [3]. In cases of retreatment, the tooth may be further weakened by the inevitable additional preparations. Thus, root fractures are considered a risk of endodontic therapy, and they are singled out as the most prevalent causes of extraction of teeth that underwent endodontic retreatment with the removal of intraradicular posts [4]. In spite of current technological advances, such as operating microscopes, ultrasonic instruments, and cone-beam computed tomography (CBCT) imaging, there is still a risk for technical failures in endodontic retreatment during access cavity preparation, especially during the removal of intraradicular posts. Complications such as perforations, deviations, or excessive removal of tooth structure will account for a poorer prognosis [8], and one should bear in mind that state-of-the-art technologies do require experienced or trained professionals [9]. The presence of a prosthetic crown is yet another complicating factor for endodontic retreatment. The way in which the operator guides access to the root canal is hindered when the crown's anatomy does not follow the root's inclination exactly, something that may require a wider access design to allow for good illumination and visualization of the operating field. Such a wider access cavity will have a significant adverse effect on the resistance of the dental crown. [10, 11]. Although restoration of the access cavity has been shown to repair the prosthetic crowns [12], these crowns will usually need replacement after endodontic treatment [13]. Guided endodontics is a recent addition to the field of endodontics that has shown promising results in improving the treatment of teeth with difficult access to root canals [14]. This approach combines the use of computerized tomography and intraoral scanning to gather detailed information about the tooth's anatomy, including the precise location and orientation of the root canals. This information is used to create a virtual 3D model, which is then used to design a customized guide. The guide is fabricated using 3D printing technology and is used to navigate through the canal system, providing accurate and precise access to the root canals.