## 1 Introduction  
In the era of modern dentistry, where dental implants are constantly on the rise, post and core treatment procedures play an important role by retaining grossly decayed teeth for a longer period of time [1]. The use of post and core restorations makes it possible to reconstruct the severely decayed teeth that have undergone endodontic therapy rather than extracting and replacing them, allowing patients to keep their own teeth [2]. After undergoing root canal therapy, teeth with severe coronal tooth structural loss are more susceptible to fracture. Following the fundamental concepts of retention and resistance form for an artificial crown for coronal restoration, a post is put in the root canal space of such teeth to support the core which provides the appropriate coronal structure [3,4]. The core part can be fabricated separately and fixed mechanically or chemically onto the post as in a prefabricated post and core system, or it can be cast along with the post as in the conventional custom cast post and core system [5]. The standard preparation for a post space constitutes parallel sides and radicular dentine walls that can be up to 1 mm thick [6]. Underneath the post space preparation, 3 to 5 mm of gutta-percha remains intact as endodontic filling material in the apical third region [7]. The required post length and the root form of teeth that have undergone endodontic treatment determine the ideal depth for post space preparation. Longer posts have greater retention of posts [8]. Typically, the teeth that need post and core restorations have minimum residual sound tooth structure. Before considering a post-core restoration, it is necessary to assess the amount of remaining tooth structure, its location, and if an adequate ferrule is available [9]. While creating the post space, attention must be exercised to prevent compromising the integrity of the apical seal [10]. When the apical seal fails to remain intact, the tooth may get reinfected and require retreatment [11]. The penetration of bacteria or other infectious materials or exudates into the root canal and vice versa from the peri-radicular spaces can be reduced by an effective apical seal [12]. Numerous studies suggest maintaining 4-5 mm of apical gutta-percha to maintain an effective apical seal [13,14]. Endodontically treated teeth with loss of significant tooth structure require sophisticated treatments that require a high level of skill and competence to restore the compromised teeth with post and core. In consideration of this, it is crucial that dentistry undergraduate students acquire adequate training prior to carrying out the post and core treatment on patients. The post and core basic procedures are provided in the preclinical training in the fixed prosthodontic curriculum at dental schools. Preclinical training has been shown to be an essential factor for ensuring a seamless transition to the clinical environment for undergraduate students [15]. In fixed prosthodontics, there is a well-established positive association between preclinical and clinical grades [16]. It has been demonstrated that teaching in dental simulation clinics is vital for preclinical education so that students may gain practical skills [17]. In preclinical fixed prosthodontic teaching methods, simulation clinic teaching has been widely employed. In these methods, students often complete a series of formative practical activities that conclude with a summative practical assessment [18]. The space between the apical portion of the post and the most coronal section of the gutta-percha that typically remains after the post has been inserted into the root canal of a tooth that has undergone endodontic therapy, can be a crucial determining factor in the prognosis of the treatment due to the presence of microorganisms. Only a few research studies have investigated how this gap may impact the clinical outcome of teeth that have undergone post and core treatment after endodontic therapy.