Comparative Evaluation of Fracture Resistance of Endodontically Treated Premolar Restored With Different Fibre Post System

International Journal of Dental Science and Innovative Research (IJDSIR) IJDSIR : Dental Publication Service Available Online at:www.ijdsir.com Volume – 8, Issue – 4, August – 2025, Page No. : 46 - 52 Corresponding Author: Dr. Arka Ray, ijdsir, Volume – 8 Issue - 4, Page No. : 46 - 52 Page46 ISSN: 2581-5989 PubMed - National Library of Medicine - ID: 101738774 Comparative Evaluation of Fracture Resistance of Endodontically Treated Premolar Restored With Different Fibre Post System 1Dr. Arka Ray, Third Year Post Graduate Student, Dept. of Conservative Dentistry & Endodontics, Haldia Institute of Dental Sciences & Research, Banbishnupur, P.OBalughata, Haldia, Purba Medinipur, West Bengal: 721645 2Dr. Asim Bikash Maity, Professor, Dept. of Conservative Dentistry & Endodontics, Haldia Institute of Dental Sciences & Research, Banbishnupur, P.OBalughata, Haldia, Purba Medinipur, West Bengal: 721645 3Dr. Sourav Bhattacharyya, Associate Professor, Dept. of Conservative Dentistry & Endodontics, Haldia Institute of Dental Sciences & Research, Banbishnupur, P.OBalughata, Haldia, Purba Medinipur, West Bengal: 721645 4Dr. Gayatri Majumder, Assistant Professor, Dept. of Conservative Dentistry & Endodontics, Haldia Institute of Dental Sciences & Research, Banbishnupur, P.OBalughata, Haldia, Purba Medinipur, West Bengal: 721645 Corresponding Author: Dr. Arka Ray, Third Year Post Graduate Student, Dept. of Conservative Dentistry & Endodontics, Haldia Institute of Dental Sciences & Research, Banbishnupur, P.OBalughata, Haldia, Purba Medinipur, West Bengal: 721645. Citation of this Article: Dr. Arka Ray, Dr. Asim Bikash Maity, Dr. Sourav Bhattacharyya, Dr. Gayatri Majumder, “Comparative Evaluation of Fracture Resistance of Endodontically Treated Premolar Restored With Different Fibre Post System”, IJDSIRAugust – 2025, Volume – 8, Issue – 4, P. No. 46 – 52. Copyright: © 2025, Dr. Arka Ray, et al. This is an open access journal and article distributed under the terms of the creative common’s attribution non-commercial License. Which allows others to remix, tweak, and build upon the work non-commercially, as long as appropriate credit is given, and the new creations are licensed under the identical terms. Type of Publication: Original Research Article Conflicts of Interest: Nil Abstract Aims: The aim of this study is to determine and compare the fracture resistance of endodontically treated teeth restored with different fibre reinforced post system. Materials and Method: A total number of 45 noncarious, single rooted human mandibular premolar teeth were selected, which were extracted for orthodontic and periodontal purpose only. After decoronation, single cone obturation and post space preparation Teeth were randomly allocated into 3 groups. Group A: Zirconia modified cylindrical fibre post (n=15); Group B: Tapered Glass fibre post (n=15); Group C: Double tapered fibre post (n=15). The different fibre post systems were cemented with paracore dual cured resin cement. Each specimen was mounted in acrylic block. Compressive loading was applied using Universal testing machine at a speed of 1mm/min in Apical direction till fracture. The fracture load was measured in newtons and converted to megapascals. Results: Statical analysis was done. Fracture resistance of human mandibular premolar teeth restored with zirconia modified cylindrical post system (Dentsply Easypost) has highest fracture resistance among the groups tested and statistically significant than the other Dr. Arka Ray, et al. International Journal of Dental Science and Innovative Research (IJDSIR) ©2025 IJDSIR, All Rights Reserved Page47 Page47 Page47 Page47 Page47 Page47 Page47 Page47 Page47 Page47 Page47 Page47 Page47 Page47 Page47 Page47 Page47 Page47 Page47 groups. teeth restored with double tapered glass fibre post (Angelus Exacto) has lowest fracture resistance among the groups tested. Conclusion: Within the parameters and limitations of this study it may be concluded that Fracture resistance of human mandibular premolar teeth restored with zirconia modified cylindrical post system (Dentsply Easypost) has highest fracture resistance among the groups tested. Keywords: Fibre post, Fracture Resistance, Zirconia Modified post, Universal Testing Machine Introduction Restoration of the mutilated endodontically treated tooth is a subject that has been evaluated and discussed widely in dental literature. The endodontically treated tooth is a unique subset of teeth requiring restoration due to the loss of the tooth structure, the changed physical characteristics by the altered collagen cross Linking. 1 A post and core are a type of dental restoration required where there is an inadequate amount of sound tooth tissue remaining to retain a conventional crown. The role of the post is firstly to retain a core restoration and crown, and secondly to redistribute stresses down onto the root, thereby reducing the risk of coronal fracture.4 Retention form is associated to prepare geometry including post's taper, length and diameter, surface texture, luting agent and passivity A post is cemented into a prepared root canal, which retains a core restoration, which retains the final crown.[5] Fibre reinforced composite posts has a high percentage of continuous reinforcing fibres in polymer matrix of epoxy resin. Resin cements are usually used for bonding of FRC posts to root canal walls. FRC materials are characterised by better functional and structural design, their mechanical properties can be tailored until it meets those of dentine and allowing the use of minimally invasive and adhesive techniques to preserve tooth structure during the restoration of ETT. 12 These posts are made of carbon, quartz or glass fibre embedded in a matrix of epoxy or methacrylate resin. The adhesion between quartz or glass fibres and resin matrix is enhanced by fibre salinization prior to embedding.10 The fibres provide strength and stiffness, while the polymeric matrix keeps the fibres together in the composite structure, protects them from the environmental harm due to elevated temperature and humidity and acts as a load transfer medium between them. Fibres represent the largest volume (from 40 to 65 vol%), contribute stiffness and strength to the matrix and determine the load-bearing capacity of FRCs structure.14 Presence of zirconia reinforced fibres aids in the strength of the fibre post system. The use of innovative fiberglass, associated with an appropriate polymer matrix, results in post translucency and high aesthetic qualities to the final restoration.13 Zirconia is a white metal; it’s flexural strength may reach 1000 Mpa while the fracture toughness of 4-5 MPa is also superior to the regular dental ceramics. One characteristic of zirconia is especially this high resistance to fractures because the tetragonal beads are transformed from the monoclinic phase, which leads to thermocompression of the forces around the defects, preventing their propagation. Aims and Objective The aim of this study is to evaluate the fracture resistance of endodontically treated teeth restored with different post core system. The objective of this study is to find which type of post and adhesives is better for endodontically treated teeth having comparatively higher resistance to fracture. Materials and Method After approval from the institutional ethical committee the study was conducted. A total number of 45 noncarious, single rooted human mandibular premolar teeth Dr. Arka Ray, et al. International Journal of Dental Science and Innovative Research (IJDSIR) ©2025 IJDSIR, All Rights Reserved Page48 Page48 Page48 Page48 Page48 Page48 Page48 Page48 Page48 Page48 Page48 Page48 Page48 Page48 Page48 Page48 Page48 Page48 Page48 were selected, which were extracted for orthodontic and periodontal purpose only. Teeth with fully formed apices, absence of calcification and having straight root canal were selected. The extracted teeth were cleaned of calculus and soft-tissue remnants employing an ultrasonic scaler (Fig 4.12) and were disinfected using 5.25 % sodium hypochlorite (Fig 4.13) for at least 30 min and rinsed with distilled water. All selected teeth were decoronated perpendicular to the long axis of the tooth by using diamond disc and air water spray coolant. The decoronation was done near the cemento-enamel junction to establish a uniform length of 16 mm of all the teeth. Length of all teeth were measured by digital callipers. A 10k (Mani, Japan) file was placed in the canal so that the tip is visible at the apical foramen. The working Length was set 1 mm short of apex. Apical enlargement was done till 15k followed by 20k hand file. During instrumentation 2ml of 5.25% sodium hypochlorite was used for irrigation. Biomechanical preparation was done using Protaper Gold file system till F3 file. Final irrigation was done with 17% EDTA solution. Once the canals were prepared, they were dried by paper points. AH Plus sealer was used for obturation of the root canal system. Obturation was done using single cone technique. Post space preparation was done till no 4 size peeso reamer (1.3 mm diameter) up to 10 mm working length from the canal orifice, leaving 5mm of gutta percha inside. The post space was irrigated with 17% EDTA and rinsed with normal saline. The samples were air dried. All the 45 human mandibular premolar samples were randomly divided into 3 groups according to the different type of fibre post systems used. Group A: Zirconia modified cylindrical fibre post (n=15); Easy Post (Dentsply Maillefer) Group B: Tapered Glass fibre post (n=15); Rely X fibre post (3M ESPE) Group C: Double tapered fibre post (n=15); Angelus Exacto fibre post system Figure 1: Testing of samples under Universal Testing Machine After post space preparation paracore dual cure resin cement was used for cementation of the post. 4 mm uniform length of post coronal to cervical margin of the tooth was kept for uniform core build up. Each specimen was mounted in a 19x 19mm x 20 mm acrylic block. Compressive loading was applied at a speed of 1mm/min plunger tip size 1mm in Apical direction. Fracture load was recorded in Newtons and Converted to Megapascal. Results and Statistical Analysis Statistical analysis was done using one way analysis of varience (ANOVA) and post hoc Tukey’s HSD test. The descriptive statistics for Fracture strength (in MPa) are presented in Table 1. Group A had the highest mean shear bond strength of 587 ± 17.3 MPa, with a range of 566 to 620 MPa, while Group B showed a lower mean of 459 ± 16.6 MPa and a range of 427 to 485 MPa. Group C demonstrated a mean of 392 ± 14.5 MPa, with values ranging from 372 to 412 MPa. Dr. Arka Ray, et al. International Journal of Dental Science and Innovative Research (IJDSIR) ©2025 IJDSIR, All Rights Reserved Page49 Page49 Page49 Page49 Page49 Page49 Page49 Page49 Page49 Page49 Page49 Page49 Page49 Page49 Page49 Page49 Page49 Page49 Page49 Table 1: Descriptive statistics of the Fracture resistance (in MPa) Groups/Descriptive summary Number of values Mean Std. Deviation Minimum Group A 15 587 17.3 566 Group B 15 459 16.6 427 Group C 15 392 14.5 372 Table 2: Inter-Group Comparisons of the Fracture resistance (in MPa) as seen in the ANOVA table Fracture resistance of human mandibular premolar teeth restored with zirconia modified cylindrical post system (Dentsply Easypost) has highest fracture resistance among the groups tested and statistically significant then the other groups. Figure 2: Inter-group Comparisons of the Fracture Strength (in MPa) Discussion In this present in vitro study, human mandibular premolar teeth were chosen as they are more susceptible to trauma and receive more angular forces.36 Hence, they were selected to represent the best possible option to simulate the clinical situations. ProTaper Gold [Dentsply Tulsa Dental Specialties, Tulsa, USA. File system was chosen for root canal preparation in this study for its unique design, greater cutting efficiency and lesser extrusion of debris apically. ProTaper Gold [Dentsply Tulsa Dental Specialties, Tulsa, USA] is a new heat-treated NiTi rotary system. ProTaper Universal was the first system to offer active cutting edges, a progressively tapered design on a single file, and both Shaping and Finishing files. ProTaper Gold [PTG] has the exact geometries as ProTaper Universal, but fortuitously has been metallurgically enhanced through heat treatment technology [21]. They were developed with proprietary advanced metallurgy and have a progressively tapered design that is claimed by the manufacturer to enhance cutting efficiency and safety. The Easy Post group (Group A) showed high fracture resistance than other groups tested, this may be attributed to the close elastic modulus of Easy Post to dentin that flexes together under loading force. Presence of zirconia reinforced fibres aids in the strength of the fibre post system. Also, the dentin-like behaviour of the post facilitates better stress distribution and yielding high fracture strength values29. An in vitro evaluation of fracture strength of endodontically treated teeth with different fibre post system have acted as a stress breaker for the system under compressive loading. This effect was reported for root reinforcement with composite resin, which resulted in the transfer of low levels of stress to the cervical region of the tooth. ANOVA table SS DF MS F (DFn, DFd) P value a Treatment (between columns) 1025349 3 341783 F (3, 56) = 1347 <0.0001* Residual (within columns) 14212 56 253.8 Total 1039561 59 Dr. Arka Ray, et al. International Journal of Dental Science and Innovative Research (IJDSIR) ©2025 IJDSIR, All Rights Reserved Page50 Page50 Page50 Page50 Page50 Page50 Page50 Page50 Page50 Page50 Page50 Page50 Page50 Page50 Page50 Page50 Page50 Page50 Page50 J K Prajapati et al (2024) concluded that ultraconservative posts (size 0) of Hi-Rem and Easy Post had greater fracture resistance than conservative posts (sizes 1 and 2). Furthermore, size 0 Hi-Rem posts performed marginally better than size 0 Easy Post. Favorable fractures are most common with both Hi-Rem and Easy Post.24 The results of this study are similar with our study. The results of this study are similar to T M Belgati et al (2018) where the author found easy post to have superior fracture resistance then that of ever stick fibre post. Sirimai and Sidoli demonstrating no root fractures for fibre post. 23 The results of this study are similar with our study. Exacto Post group (Group C) showed approximately half the fracture strength of teeth restored with zirconia modified posts. This lower fracture strength compared with the values of with zirconia modified posts. may be attributed to the displacement or fracture of the resin cement layer, composite core, or resin post during mechanical testing. Material property of the post has been shown to affect the stress distribution.28 M Chirila et al (2016) The fracture resistance of the teeth endodontically treated and restored with FRC posts, respectively Exacto and Reforpost (Angelus), did not register statistically significant differences.28 which is in agreement with our study. A Jayasenthil et al (2016) conducted a study was to relate the fracture resistance of endodontically treated teeth in relation to post geometry. They concluded that The Parallel design had lesser number of catastrophic failure and had better fracture resistance. Teeth restored with Reforpost showed highest fracture resistance followed by Parapost and Exacto conical.28 which is in agreement with our study. Therefore, from this study it can be agreed that the fibre post has characteristics simulating natural dentinal structure than any other previously used post and it acts as a shock-absorber, dissipating much stresses on the finished restoration with small fraction forces to dentinal walls thus demonstrating restorable fractures. The composite core has excellent adaption and forms strong bond to remaining tooth structure, bondable posts, resin cements, and ultimately the final restoration creating the Monoblock. In addition, it is aesthetic, simple and predictable25 bonding every component directly or indirectly thus reinforces the intra-radicular tooth structure with excellent transverse strength.26 It is more favourable when two substances of equivalent or almost near modulus of elasticity approximate each other. limitations of the study include not simulating the periodontal ligament space. Roots were embedded directly into the resin blocks. In our study the tests were carried out in single rooted teeth, with specific dimensions and testing done under a static compressive loading applied at a single point and at a fixed angulation. Thus, dynamic or fatigue behaviours cannot be inferred. Methodologically, the limitation of this study was that static loading testing was used to evaluate fracture resistance. Conclusion Within the parameters and limitations of the in-vitro study it may be concluded that Fracture resistance of human mandibular premolar teeth restored with zirconia modified cylindrical post system (Dentsply Easypost) has highest fracture resistance among the groups tested and statistically significant then the other groups. Human mandibular premolar teeth restored with double tapered glass fibre post (Angelus Exacto) has lowest fracture resistance among the groups tested. Dr. Arka Ray, et al. International Journal of Dental Science and Innovative Research (IJDSIR) ©2025 IJDSIR, All Rights Reserved Page51 Page51 Page51 Page51 Page51 Page51 Page51 Page51 Page51 Page51 Page51 Page51 Page51 Page51 Page51 Page51 Page51 Page51 Page51 References 1. Gutmann JL. The dentin-root complex: anatomic and biologic considerations in restoring endodontically treated teeth. The Journal of prosthetic dentistry. 1992; 67(4):458-67. 2. Helfer AR, Melnick S, Schilder H. 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