Journal of Research in Dental and Maxillofacial Sciences

en Effect of Gap Size between the Intracanal Post and Gutta-Percha on Stress Distribution in Teeth with Post-and-Core Restorations: A Finite Element Analysis Endodontics Endodontics Original article Original article <div style="text-align: justify;">Background and Aim: This study evaluated the effect of gap size between the intracanal post and gutta-percha on stress distribution in teeth with post-and-core restorations using finite element analysis (FEA).    Materials and Methods: In this FEA, eight 3D models of maxillary central incisors were created: four with fiber-reinforced composite posts (FRCPs) and four with nickel-chromium metal cast posts (MCPs). Also, 0 mm (no gap), 1 mm, 2 mm, and 3 mm gaps were modeled. A 100-N oblique load (at 135 degrees relative to the longitudinal tooth axis) was applied, and the von Mises (VM), tensile, and compressive stress values were analyzed.    Results: For the FRCPs, the VM stress patterns in dentin remained consistent in presence of 0-2 mm gap, but a 3-mm gap increased stress by 35%-37%. The MCP models showed similar stress distribution patterns across different gap sizes, with a peak VM stress (13.11 MPa) localized at the buccal mid-root. The FRCPs demonstrated uniform stress distribution; whereas, the MCPs exhibited higher overall stress levels by 85%-89%. Conclusion: The results indicated that a 3-mm gap significantly elevated dentinal stress, increasing the fracture risk. The FRCPs with ≤ 2 mm gap had an optimal performance; whereas, the MCPs induced higher stress levels regardless of the gap size. Failure modes differed as well, such that the FRCPs were predisposed to cervical fractures, whereas the MCPs increased the risk of apical fractures. These findings highlight the importance of management of intracanal post-gutta-percha gap as a critical parameter in post-and-core restorations to mitigate biomechanical failure.  </div> Dental Stress Analysis, Post and Core Technique, Root Canal Therapy 114 125 http://jrdms.dentaliau.ac.ir/browse.php?a_code=A-10-3291-1&slc_lang=en&sid=1 Soheil Niavarzi soheil.niavarzi@gmail.com 100319475328460016917 100319475328460016917 No Private Endodontist, Tehran, Iran Farideh Geramipanah geramipa@tums.ac.ir 100319475328460016918 100319475328460016918 No Department of Prosthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran Leila Sedighpour Lsedigh@yahoo.com 100319475328460016919 100319475328460016919 No Department of Prosthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran Mohammad Marvi Mohammadmarvi.68@gmail.com 100319475328460016920 100319475328460016920 Yes Department of Endodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.