Influence of dental restorations and mastication loadings on dentine fatigue behaviour: Image-based modelling approach.
OBJECTIVE
The aim of this study was to use Finite Element Analysis (FEA) to estimate the influence of various mastication loads and different tooth treatments (composite restoration and endodontic treatment) on dentine fatigue. The analysis of fatigue behaviour of human dentine in intact and composite restored teeth with root-canal-treatment using FEA and fatigue theory was performed.


METHODS
Dentine fatigue behaviour was analysed in three virtual models: intact, composite-restored and endodontically-treated tooth. Volumetric change during the polymerization of composite was modelled by thermal expansion in a heat transfer analysis. Low and high shrinkage stresses were obtained by varying the linear shrinkage of composite. Mastication forces were applied occlusally with the load of 100, 150 and 200N. Assuming one million cycles, Fatigue Failure Index (FFI) was determined using Goodman's criterion while residual fatigue lifetime assessment was performed using Paris-power law.


RESULTS
The analysis of the Goodman diagram gave both maximal allowed crack size and maximal number of cycles for the given stress ratio. The size of cracks was measured on virtual models. For the given conditions, fatigue-failure is not likely to happen neither in the intact tooth nor in treated teeth with low shrinkage stress. In the cases of high shrinkage stress, crack length was much larger than the maximal allowed crack and failure occurred with 150 and 200N loads. The maximal allowed crack size was slightly lower in the tooth with root canal treatment which induced somewhat higher FFI than in the case of tooth with only composite restoration.


CONCLUSIONS
Main factors that lead to dentine fatigue are levels of occlusal load and polymerization stress. However, root canal treatment has small influence on dentine fatigue.


CONCLUSIONS
The methodology proposed in this study provides a new insight into the fatigue behaviour of teeth after dental treatments. Furthermore, it estimates maximal allowed crack size and maximal number of cycles for a specific case.
Faculty of Engineering, University of Kragujevac, Sestre Janjic 6, 34000 Kragujevac, Serbia; Bioengineering Research and Development Center Kragujevac, Prvoslava Stojanovica 6, 34000 Kragujevac, Serbia.
Arso M
AM
Vukicevic
University of Belgrade - School of Medicine, Institute of Anatomy, Laboratory for Anthropology, 4/2 Dr Subotica, 11000 Belgrade, Serbia.
Ksenija
K
Zelic
Faculty of Engineering, University of Kragujevac, Sestre Janjic 6, 34000 Kragujevac, Serbia. Electronic address: gjovicic.kg.ac.rs@gmail.com.
Gordana
G
Jovicic
University of Belgrade - School of Medicine, Institute of Anatomy, Laboratory for Anthropology, 4/2 Dr Subotica, 11000 Belgrade, Serbia.
Marija
M
Djuric
Faculty of Engineering, University of Kragujevac, Sestre Janjic 6, 34000 Kragujevac, Serbia; Bioengineering Research and Development Center Kragujevac, Prvoslava Stojanovica 6, 34000 Kragujevac, Serbia.
Nenad
N
Filipovic
D003188:Composite Resins / Q000737:chemistry; D003198:Computer Simulation; D003793:Dental Restoration, Permanent; D003799:Dental Stress Analysis / Q000379:methods; D003804:Dentin / Q000293:injuries*; D020342:Finite Element Analysis; D015775:Fractures, Stress; D006801:Humans; D008409:Mastication / Q000502:physiology*; D008954:Models, Biological; D011474:Prosthesis Design; D019553:Tooth, Nonvital
D003188:Composite Resins
Fatigue; Finite element method; Human dentine; Image-based modelling; Mastication