The Effect of Different Ferrule Configurations and Preparation Designs on the Fatigue Performance of Endodontically Treated Maximillary Central Incisors: A 3D Finite Element Analysis  
[PERSON]  
1 Department of Prosthodntics, Faculty of Dentistry, Necmettin Erbakan University, 42090 Konya, Turkey 1  
[PERSON]  
2 Faculty of Dentistry, Necmettin Erbakan University, 42090 Konya, Turkey 2  
Footnote 1: email: {mehmet.gokberkkaan.edu.tr}  
Footnote 2: email: {mehmet.gokberkkaan.edu.tr}  
Footnote 3: email: {mehmet.gokberkkaan.edu.tr}  
Footnote 4: email: {mehmet.  
Given these circumstances, the clinician may have to apply treatment with many different ferrule configurations. In particular, configurations without labial and palatal walls are more challenging for the clinician. [PERSON] et al. and [PERSON] et al. reported the importance of the presence of the palatal wall [1; 8], [PERSON] et al. argued that different ferrule configurations did not affect biomechanical behavior [9], and [PERSON] et al. stated that the internal retention shape would be useful in terms of root strength [5]. However, the effect of different ferrule configurations on rehabilitation with post-core systems has not been sufficiently studied.  
In dentistry, endocrowns, which were introduced around three decades ago with the development of adhesive technologies and new materials, are widely clinically used today. Endocrowns are prostheses prepared as monoblocks and cemented to the pulp chamber's internal wall and margins. They adequately restore the tooth's anatomy and prevent bacterial recolonization by closing the root canal, thus ensuring longer survival after endodontic treatment [10]. Clinical trials have not reached a consensus on the biomechanical behaviors of endocrown and post-core restorations. While [PERSON] and [PERSON] [11] and [PERSON] et al. [12] argue that post-core restorations are preferable, [PERSON] [11], [PERSON] [13], and [PERSON] et al. [14] report that endocrown restorations exhibit greater fracture strength.  
Glass ceramics have brittle behavior and low tensile strength, which can lead to catastrophic fractures even at low stresses. With advances in dental ceramic formulations, glassy phase infiltrated lithium disilicate (LS) ceramic systems have been introduced [15]. These ceramics are used in fully anatomical monolithic crowns, particularly for maxillary incisional tooth restoration due to their increased durability and preferred transparency. Although the long-term success rate of glass ceramics is satisfactory, the development of polymer-infiltrated ceramic network (PICN) ceramics has become increasingly popular in dentistry due to its clinically successful use [16]. It has also been suggested that polymer-based composites combine the properties of both the ceramic and polymer, resulting in hybrid materials with performance and mechanical behavior closer to that of teeth [17].  
This study aimed to evaluate the fatigue performance of post-core and endocrown restorations (made with adhesively cemented LS and PICN restorative materials) applied to different ferrule configurations by means of finite element analysis. Clinicians may think that the fatigue performance of post-core and endocrown restorations is affected by different materials and ferrule configurations (H1), and a null hypothesis (H0) was proposed in that neither the restorative materials and restoration types nor different ferrule configurations would affect fatigue performance.