Basic Research| Volume 47, ISSUE 9, P1472-1480, September 2021

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Impact of Canal Taper and Access Cavity Design on the Life Span of an Endodontically Treated Mandibular Molar: A Finite Element Analysis



      This study investigated the impact of different canal tapers and access cavity designs on the life span of endodontically treated mandibular first molars using the finite element method.


      Finite element analysis was performed on simulated models with 3 access cavity designs (traditional, conservative, and truss). The mesial canals were prepared to either constant tapers of 25/.04 and 25/.06 or a variable taper corresponding to the cumulative canal preparation shapes of TruNatomy Prime (Dentsply Sirona, Charlotte, NC) and ProTaper Gold F2 (Dentsply Sirona). The distal canals in all models had a 40/.04 preparation. Using occlusal fingerprint analysis, all models were subjected to cyclic occlusal loading until model failure. The number of cycles until failure, the location of failure, stress distribution patterns, and the maximum von Mises stresses were assessed.


      The traditional access models showed a lower life span than the conservative and truss models regardless of the canal taper, whereas there was not a notable difference in the conservative and truss models. The stresses migrated apically along the root surface and remarkably on the mesial aspect of the mesial root and the furcation area’s outer surface. After root canal preparation with different tapers, there were no evident changes in the pattern and magnitude of the stresses distributed along the root surface.


      The life span of the tooth is affected more significantly by the access cavity design than the root canal preparation taper. Because stress patterns migrate apically rather than concentrate in the pericervical area, crack initiation and propagation might occur anywhere on the root surface.

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        • Landys Borén D.
        • Jonasson P.
        • Kvist T.
        Long-term survival of endodontically treated teeth at a public dental specialist clinic.
        J Endod. 2015; 41: 176-181
        • Kishen A.
        Mechanisms and risk factors for fracture predilection in endodontically treated teeth.
        Endod Topics. 2006; 13: 57-83
        • Tamse A.
        • Fuss Z.
        • Lustig J.
        • Kaplavi J.
        An evaluation of endodontically treated vertically fractured teeth.
        J Endod. 1999; 25: 506-508
        • Lertchirakarn V.
        • Palamara J.E.
        • Messer H.H.
        Patterns of vertical root fracture: factors affecting stress distribution in the root canal.
        J Endod. 2003; 29: 523-528
        • Gluskin A.H.
        • Peters C.I.
        • Peters O.A.
        Minimally invasive endodontics: challenging prevailing paradigms.
        Br Dent J. 2014; 216: 347-353
        • Silva E.J.
        • Pinto K.P.
        • Ferreira C.M.
        • et al.
        Current status on minimal access cavity preparations: a critical analysis and a proposal for a universal nomenclature.
        Int Endod J. 2020; 53: 1618-1635
        • Clark D.
        • Khademi J.
        Modern molar endodontic access and directed dentin conservation.
        Dent Clin North Am. 2010; 54: 249-273
        • Neelakantan P.
        • Khan K.
        • Hei Ng G.P.
        • et al.
        Does the orifice-directed dentin conservation access design debride pulp chamber and mesial root canal systems of mandibular molars similar to a traditional access design?.
        J Endod. 2018; 44: 274-279
        • Saber S.M.
        • Hayaty D.M.
        • Nawar N.N.
        • Kim H.C.
        The effect of access cavity designs and sizes of root canal preparations on the biomechanical behavior of an endodontically treated mandibular first molar: a finite element analysis.
        J Endod. 2020; 46: 1675-1681
        • Jiang Q.
        • Huang Y.
        • Tu X.
        • et al.
        Biomechanical properties of first maxillary molars with different endodontic cavities: a finite element analysis.
        J Endod. 2018; 44: 1283-1288
        • Rundquist B.D.
        • Versluis A.
        How does canal taper affect root stresses?.
        Int Endod J. 2006; 39: 226-237
        • Sathorn C.
        • Palamara J.E.
        • Palamara D.
        • Messer H.H.
        Effect of root canal size and external root surface morphology on fracture susceptibility and pattern: A finite element analysis.
        J Endod. 2005; 3: 288-289
        • Nakamura Y.
        • Kanbara R.
        • Ochiai K.T.
        • Tanaka Y.
        A finite element evaluation of mechanical function for 3 distal extension partial dental prosthesis designs with a 3-dimensional nonlinear method for modeling soft tissue.
        J Prosthet Dent. 2014; 112: 972-980
        • Li L.L.
        • Wang Z.Y.
        • Bai Z.C.
        • et al.
        Three-dimensional finite element analysis of weakened roots restored with different cements in combination with titanium alloy posts.
        Chin Med J (Engl). 2006; 119: 305-311
        • Kinney J.H.
        • Marshall S.J.
        • Marshall G.W.
        The mechanical properties of human dentin: a critical review and re-evaluation of the dental literature.
        Crit Rev Oral Biol Med. 2003; 14: 13-29
        • Gao S.S.
        • An B.B.
        • Yahyazadehfar M.
        • et al.
        Contact fatigue of human enamel: experiments, mechanisms and modeling.
        J Mech Behav Biomed Mater. 2016; 60: 438-450
        • Lanza A.
        • Aversa R.
        • Rengo S.
        • et al.
        3D FEA of cemented steel, glass and carbon posts in a maxillary incisor.
        Dent Mater. 2005; 21: 709-715
        • Holmes D.C.
        • Diaz-Arnold A.M.
        • Leary J.M.
        Influence of post dimension on stress distribution in dentin.
        J Prosthet Dent. 1996; 75: 140-147
        • Yaman S.D.
        • Alaçam T.
        • Yaman Y.
        Analysis of stress distribution in a maxillary central incisor subjected to various post and core applications.
        J Endod. 1998; 24: 107-111
        • Kullmer O.
        • Benazzi S.
        • Fiorenza L.
        • et al.
        Technical note: occlusal fingerprint analysis: quantification of tooth wear pattern.
        Am J Phys Anthropol. 2009; 139: 600-605
        • Rosentritt M.
        • Siavikis G.
        • Behr M.
        • et al.
        Approach for valuating the significance of laboratory simulation.
        J Dent. 2008; 36: 1048-1053
        • Rosentritt M.
        • Kolbeck C.
        • Handel G.
        • et al.
        Influence of the fabrication process on the in vitro performance of fixed dental prostheses with zirconia substructures.
        Clin Oral Investig. 2011; 15: 1007-1012
        • van der Vyver P.J.
        • Vorster M.
        • Peters O.A.
        Minimally invasive endodontics using a new single-file rotary system.
        Int Dent Afr Ed. 2014; 9: 6-20
        • Arola D.
        Fatigue testing of biomaterials and their interfaces.
        Dent Mater. 2017; 33: 367-381
        • Mireku A.S.
        • Romberg E.
        • Fouad A.F.
        • Arola D.
        Vertical fracture of root filled teeth restored with posts: the effects of patient age and dentine thickness.
        Int Endod J. 2010; 43: 218-225
        • PradeepKumar A.R.
        • Shemesh H.
        • Jothilatha S.
        • et al.
        Diagnosis of vertical root fractures in restored endodontically treated teeth: a time-dependent retrospective cohort study.
        J Endod. 2016; 42: 1175-1180
        • Benazzi S.
        • Kullmer O.
        • Grosse I.R.
        • Weber G.W.
        Using occlusal wear information and finite element analysis to investigate stress distributions in human molars.
        J Anat. 2011; 219: 259-272
        • Wang Q.
        • Liu Yu
        • Wang Z.
        • et al.
        Effect of access cavities and canal enlargement on biomechanics of endodontically treated teeth: A finite element analysis.
        J Endod. 2020; 46: 1501-1507
        • Smoljan M.
        • Hussein M.O.
        • Guentsch A.
        • Ibrahim M.
        Influence of progressive versus minimal canal preparations on the fracture resistance of mandibular molars: a 3-dimensional finite element analysis.
        J Endod. 2021; 47: 932-938
        • Plotino G.
        • Grande N.M.
        • Isufi A.
        • et al.
        Fracture strength of endodontically treated teeth with different access cavity designs.
        J Endod. 2017; 43: 995-1000
        • Sabeti M.
        • Kazem M.
        • Dianat O.
        • et al.
        Impact of access cavity design and root canal taper on fracture resistance of endodontically treated teeth: an ex vivo investigation.
        J Endod. 2018; 44: 1402-1406
        • Moore B.
        • Verdelis K.
        • Kishen A.
        • et al.
        Impacts of contracted endodontic cavities on instrumentation efficacy and biomechanical responses in maxillary molars.
        J Endod. 2016; 42: 1779-1783
        • Corsentino G.
        • Pedullà E.
        • Castelli L.
        • et al.
        Influence of access cavity preparation and remaining tooth substance on fracture strength of endodontically treated teeth.
        J Endod. 2018; 44: 1416-1421
        • De Boever J.A.
        • McCall Jr., W.D.
        • Holden S.
        • Ash Jr., M.M.
        Functional occlusal forces: An investigation by telemetry.
        J Prosthet Dent. 1978; 40: 326-333
        • Bates J.F.
        • Stafford G.D.
        • Harrison A.
        Masticatory function—a review of the literature: III. Masticatory performance and efficiency.
        J Oral Rehabil. 1976; 3: 57-67
        • Tang We
        • Wu Y.
        • Smales R.J.
        Identifying and reducing risks for potential fractures in endodontically treated teeth.
        J Endod. 2010; 36: 609-617
        • Ren L.M.
        • Wang W.X.
        • Takao Y.
        • Chen Z.X.
        Effects of cementum-dentine junction and cementum on the mechanical response of tooth supporting structure.
        J Dent. 2010; 38: 882-891