Comparison of mechanical property and role between enamel and dentin in the human teeth

Abstract

The mechanical properties of enamel and dentin were studied using test specimens having the same shape and dimensions because these properties might vary with the experimental conditions and specimen shapes and dimensions. Healthy human teeth were used as specimens for mechanical tests. The stress (MPa), strain (%), and elastic modulus (E, MPa) of the specimens were obtained from compression tests. The maximum stresses of the enamel, dentin, and enamel–dentin specimens were 62.2 ± 23.8, 193.7 ± 30.6, and 126.1 ± 54.6 MPa, respectively. The maximum strains of the enamel, dentin, and enamel–dentin specimens were 4.5 ± 0.8%, 11.9 ± 0.1%, and 8.7 ± 2.7%, respectively. The elastic moduli of the enamel, dentin, and enamel–dentin specimens were 1338.2 ± 307.9, 1653.7 ± 277.9, and 1628.6 ± 482.7 MPa, respectively. The measured hardness value of enamel specimens (HV = 274.8 ± 18.1) was around 4.2 times higher than that of dentin specimens (HV = 65.6 ± 3.9). Judging from the measured values of the stress and strain of enamel specimens, enamel tended to fracture earlier than dentin; therefore, it was considered more brittle than dentin. However, judging from the measured hardness values, enamel was considered harder than dentin. Therefore, enamel has higher wear resistance, making it suitable for grinding and crushing foods, and dentin has higher force resistance, making it suitable for absorbing bite forces. The different mechanical roles of enamel and dentin may arise from their different compositions and internal structures, as revealed through scanning electron micrographs of enamel and dentin.

Sintering of the Tricalcium Phosphate-Titania-Magnesium Fluoride Composites

“…These values are relatively similar to those of the bone tissues and precisely the enamel [6,8,[67][68][69][70]. Thus, the enamel is mainly made of the mineral in the calcium phosphate [69,71]. It is the hardest tissue in the human body because it contains almost no water [69].…”

“…Thus, the enamel is mainly made of the mineral in the calcium phosphate [69,71]. It is the hardest tissue in the human body because it contains almost no water [69]. For this reason, it is good to get a similar behavior as enamel.…”

“…For this reason, it is good to get a similar behavior as enamel. In fact, Chun et al studied the mechanical properties of both enamel and dentin [69].…”

Bonding state of metal-free CAD/CAM onlay restoration after cyclic loading with and without immediate dentin sealing

“…It could therefore be considered that restorations with IDS ensure clinical cases compared to the restoration without IDS. The manufacturerreported modulus of elasticity of the Filtek Supreme Ultra Flowable Restorative (6.8 GPa) 41) and Rely X Ultimate (7.7 GPa) 42) can be compared with the elasticity value of human dentin (approximately 16 GPa) 43) . Under cyclic loading, the part of IDS that is composed of Filtek Supreme Ultra Flowable Restorative may demonstrate the greatest flexibility at the interfacial zone consisting of dentin, resin cement (Rely X Ultimate), and sealing material, thereby providing an excellent buffer effect as a stress-breaker.…”

Modeling the Stress State of Hard Tissues of a Tooth in the Process of Restoration of Class I Carious Cavities

“…Mechanical role of the enamel is to protect the dentine because of its high wear, and mechanical role of dentine is to absorb the power load because of its high strength resistance [4].…”