Numerical analysis of the biomechanical behaviour of a weakened root after adhesive reconstruction and post-core rehabilitation

• Published in: Journal of dentistry Vol. 40; no. 5; pp. 423 - 432
• Main Authors: Mattos, C.M.A, Las Casas, E.B, Dutra, I.G.R, Sousa, H.A, Guerra, S.M.G
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.05.2012; Elsevier Limited
• Subjects: Adhesive strength; Biomechanical Phenomena; Biomechanics; Cement; Chromium Alloys - chemistry; Composite Resins - chemistry; Computer Simulation; Crowns; Dental Materials - chemistry; Dental Prosthesis Design; Dental restoration failure; Dental Stress Analysis; Dentin - physiopathology; Dentistry; Elastic Modulus; Finite Element Analysis; Glass - chemistry; Humans; Imaging, Three-Dimensional - methods; Incisor - physiopathology; Mathematical models; Models, Biological; Numerical Analysis, Computer-Assisted; Post and Core Technique; Prostheses; Reconstruction; Rehabilitation; Roots; Standard deviation; Stress concentration; Stress, Mechanical; Studies; Teeth; Tooth Cervix - physiopathology; Tooth fractures; Tooth Fractures - physiopathology; Tooth Root - physiopathology; Tooth, Nonvital - physiopathology; Tooth, Nonvital - rehabilitation; Walls; Dental restoration failure; Dental stress analysis; Post and core technique; Finite element analysis; Tooth fractures
• ISSN: 0300-5712; 1879-176X
• DOI: 10.1016/j.jdent.2012.02.004

Abstract Objectives The purpose of this study was to perform a finite element analysis to determine whether adhesive reconstruction is able to restore the original biomechanical behaviour of weakened roots, in terms of fracture resistance, when compared with post/crown-restored teeth with intact roots. Methods A three-dimensional model of a maxillary central incisor was created. The model simulated an endodontically treated tooth restored with a glass-fibre post, a composite-resin core and a metal crown (Model 1). Based on Model 1, a new volume was created in the root cervical third that represented the area where the dentine structure was lost, resulting in a structurally damaged root (Model 2). A 100 N load was applied to the palatal surface at 130° from the long axis of the tooth. After processing (Ansys® 10.0 – Canonsburg, PA, USA), the principal normal stress data were analyzed ( S1 , tensile; S3 , compressive). Results The models demonstrated a similar S1 distribution concentrated in the lingual cervical region but different S1 levels (Model 1: 28.7 MPa; Model 2: 35.3 MPa). The S3 distribution indicated differences in behaviour between the models (Model 1: −18 to −27 MPa along the buccal root surface; Model 2: −25 to −32 MPa on the post buccal surface and along the buccal root wall). Conclusions Although the stress distribution within the root walls remained below the ultimate stress limit of the root dentine, the adhesive reconstruction of the weakened roots did not recover the load resistance of structurally intact roots. Clinical significance The decision of when to prosthetically rehabilitate weakened roots with cervical dentine structural tissue loss is a challenge for clinicians. A ‘monoblock’ adhesive reconstruction has been proposed for root reinforcement. During treatment planning, the possibility of restoring the mechanical resistance of the root must be evaluated if successful long-term results are to be achieved.