Evaluation Of The Impact Of Different Access Cavity Designs On Stress Distribution And Biomechanical Preparation Of Mandibular Premolars: A Three-Dimensional Finite Element Analysis

Finite Element Analysis; Endodontics; Stress Distribution; Tooth Fractures; Access Cavity Preparation; Mandibular Premolars.

Khalifa Almarshud1:
1
Postgraduate Endodontic Resident,
Department of Conservative Dental
Sciences, College of Dentistry, Qassim
University, Buraidah 52571, Saudi Arabia,
Email: 431118346@qu.edu.sa , ORCID:
0009-0005-7082-2602
Hanan Alharbi2:
2
Assistant Professor of Endodontics,
Department of Conservative Dental
Sciences, College of Dentistry, Qassim
University, Buraidah 52571, Saudi Arabia,
Email: Al.Hanan@qu.edu.sa , ORCID:
0000-0001-7383-9024
Nawaf Almutairi3:
3
Associate Professor of Endodontics,
Department of Conservative Dental
Sciences, College of Dentistry, Qassim
University, Buraidah 52571, Saudi
Arabia,Email: nawaf.almutairi@qu.edu.sa
, ORCID: 0009-0008-0542-2647
Mustafa Alattas4:
4
Associate Professor of Endodontics,
Department of Conservative Dental
Sciences, College of Dentistry, Qassim
University, Buraidah 52571, Saudi Arabia,
Email: M.AlAttas@qu.edu.sa , ORCID:
0000-0001-5690-0890
Ahmed N. Mohamed5:
5
Professor of Endodontics, Department of
Conservative Dentistry, Faculty of
Dentistry, Alexandria University,
Alexandria 21526, Egypt
Email: ahmed.nabil@alexu.edu.eg ,
ORCID: 0009-0009-4749-614X
Manal M. Abdelhafeez6*: Corresponding

6
Professor of Endodontics, Department of
Conservative Dental Sciences, College of
Dentistry, Qassim University, Buraidah
52571, Saudi Arabia,
Email: m.abdelhafeez@qu.edu.sa ,
ORCID: 0000-0003-4391-9562
*Corresponding: Author: Manal M.
Abdelhafeez
Email (m.abdelhafeez@qu.edu.sa)

European Journal of Prosthodontics and Restorative Dentistry (2026) 34 (2), 29–37

Evaluation Of The Impact Of
Different Access Cavity Designs
On Stress Distribution And
Biomechanical Preparation Of
Mandibular Premolars: A
Three-Dimensional
Finite
Element Analysis
--------------------------------------------------------------------Abstract
Objectives: Endodontically treated teeth are prone to fracture because of the
structural loss resulting from caries and treatment procedures. Access cavity
design significantly influences tooth biomechanics; however, the comparative
performance of traditional (TAC), conservative (CAC), and caries-driven (CDA)
designs for mandibular premolars remains unclear. We aimed to evaluate and
compare stress distributions in a mandibular second premolar under different
access cavity designs using finite element analysis (FEA).
Methods: Three-dimensional FEA (3D-FEA) was performed to assess stress
distributions. A finite element model of a human mandibular second premolar
was created from cone-beam computed tomography scans. Four models were
simulated: intact Tooth (IT), TAC, CAC, and CDA. All cavities were restored
with composite resin. A 200N static vertical load was applied to the occlusal
surface, and the von Mises stress distributions in the enamel, dentin, composite
restoration, and root sections were analyzed at six levels.
Results: The CAC design produced the highest enamel stress (508.9 MPa),
representing more than fourfold increase compared with the intact tooth (95.2
MPa). The TAC design yielded the highest dentin stress (89.3 MPa). The CDA
design exhibited the most favorable biomechanical performance, with the lowest
stress values across the enamel (91.7 MPa), dentin (51.6 MPa), and composite
restoration (55.5 MPa), along with the most uniform stress distribution.
Conclusions: The CDA design showed superior biomechanical performance by
preserving tooth structure and optimizing stress distribution. The CAC design,
while preserving dentin, creates critical enamel stress concentrations and
increases the fracture risk.
Clinical Significance: Within the limitations of this three-dimensional finite
element study, a caries-driven access design in mandibular second premolars
showed the most favorable biomechanical behavior after endodontic treatment.
This approach may assist clinicians preserve tooth structure and reduce stress
concentration-related fracture risk compared with traditional or conservative
access cavity designs.

Fractured teeth treated endodontically (ETT) are more prone to fracture, which is mainly the result of carious loss of tooth structure, trauma, and endodontic treatment procedures [1-4]. To maintain the survival and prognosis of ETT, it is important to preserve the tooth structure [5]. The recent trend in dentistry is minimally invasive dentistry (MID) aiming to preserve healthy tooth structures and produce the best treatment outcomes [6-8]. This has transferred to ••••••••••••••••••••••••••••••••

Received: 15.02.2026

EJPRD

Accepted: 08.04.2026 ejprd.org - Published by Riset Publishing Services LLC.

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