Evaluation of the coefficient of thermal expansion of human and bovine dentin by thermomechanical analysis

Abstract

The mismatch of thermal expansion and contraction between restorative materials and tooth may cause stresses at their interface, which may lead to microleakage. The present work compared the coefficient of thermal expansion (CTE) with the thermomechanical behavior of human and bovine teeth and determined if the CTE is a suitable parameter to describe tooth behavior. Fifteen human third molar and 15 bovine incisor tooth slices (6×5×2 mm) were allocated to 3 groups according to the test environment: G1 - room condition, G2 - 100% humidity, G3 - desiccated and tested in dry condition. Each specimen was weighed, heated from 20 to 70ºC at 10ºC min-1 and reweighed. The CTE was measured between 20 and 50ºC. Fresh dentin (human -0.49% ± 0.27, bovine -0.22% ± 0.16) contracted on heating under dry condition. Under wet conditions, only human teeth (-0.05% ± 0.04) showed contraction (bovine 0.00% ± 0.03) accompanied by a significantly lower (p<0.05) weight loss than in dry specimens (human 0.35% ± 0.15, bovine 0.45% ± 0.20). The desiccated dentin expanded on heating without obvious weight changes (0.00% ± 0.00). The CTE found was, respectively, in dry, wet and dissected conditions in ºC(-1): human (-66.03×10(-6), -6.82×10(-6), 5.52×10(-6)) and bovine (-33.71×10(-6), 5.47×10(-6), 4.31×10(-6)). According to its wet condition, the dentin showed different CTEs. The thermal expansion behavior of human and bovine dentin was similar. A simple evaluation of the thermal expansion behavior of tooth structure by its CTE value may not be appropriate as a meaningful consideration of the effects on the tooth-material interface.

Mechanical and thermal stress evaluation of PEEK prefabricated post with different head design in endodontically treated tooth: 3D-finite element analysis

“…mechanical loadings on endodontically restored teeth should be analyzed as a whole, in order to locate the areas of high-stress concentration which subsequently jeopardize the long-term survival rate of bonding between layers of restoration and remaining tooth structure leading to coronal leakage, degradation of the tooth tissues and restoration 29,30) . Fortunately, with rapid improvements in computer technology, finite element analysis (FEA) enables the user to accurately simulate a complex design like a post-crown endodontic restoration system and natural condition of oral cavity by entering various environmental parameters and tissue properties, overcoming the ethical issues and difficulties regarding medical studies 31) .…”

Stress behaviour across human tooth by temperature gradient resulting of laser irradiation

“…By replacing these terms and Equations. (9) and (10) into the Equation. (3), the final result will be: where the main coefficients (such as Γ1, Γ2 and Γ3) were defined as below:…”

“…Goodis et al [8] studied pulpal safety of tooth irradiated by 9.6μm laser with a repetition rate of 10Hz of microsecond pulses and reported this pulsed laser beam as a reliable and safe tool for caries prevention in human tooth. Lopez et al [9] compared the Coefficient of Thermal Expansion (CTE) with the thermo-mechanical behavior of human teeth and determined if the CTE is a suitable parameter to describe tooth behavior. The thermal strain was measured between 20 and 50ºC.…”

Incorporating nano graphene oxide to poly-methyl methacrylate; antibacterial effect and thermal expansion.

“…Thermal expansion and contraction is an essential property for material used in restorative dentistry because oral cavity and tooth structure are subjected to wide range of temperature fluctuations [14]. Linear coefficient of thermal expansion (α) is normally used to describe the fractional dimensional changes of a substance in response to thermal stimuli [14,15]. Thermal stresses developed at the interface between PMMA and other materials as tooth structure, artificial teeth..etc.…”

“…Thermal stresses developed at the interface between PMMA and other materials as tooth structure, artificial teeth..etc. when there is a mismatch of α [5,14] lead to leakage, percolation , damage and fracture limiting the usage of PMMA [16].…”