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Ultimate tensile strength of tooth structures
Marcelo Giannini1, Carlos José Soares, Ricardo Marins de Carvalho
1Department of Restorative Dentistry, Piracicaba School of Dentistry, University of Campinas, Av. Limeira, 901, Piracicaba, SP, Brazil. giannini@fop.unicamp.br
Summary
The ultimate tensile strength of dental enamel, dentin, and the dentin-enamel junction varies significantly based on their location and structural orientation. This study highlights key differences in the mechanical properties of these dental tissues.
Area of Science:
- Biomaterials Science
- Dental Materials
- Mechanical Properties of Tissues
Background:
- Understanding the mechanical properties of dental tissues is crucial for developing effective restorative materials and procedures.
- The ultimate tensile strength (UTS) of enamel, dentin, and the dentin-enamel junction (DEJ) can be influenced by their composition and structural arrangement.
Purpose of the Study:
- To determine the ultimate tensile strength (UTS) of human enamel (E), dentin (D), and the dentin-enamel junction (DEJ) using the microtensile technique.
- To investigate how the UTS of these dental structures varies with location and orientation.
Main Methods:
- Extracted human third molars were used, with occlusal enamel surfaces etched and bonded with a one-bottle adhesive system.
- Teeth were sectioned into slabs, trimmed into dumbbell-shaped specimens (approx. 0.5 mm² cross-sectional area) at E, D, or DEJ.
- Enamel was tested parallel (EP) and transversal (ET) to its prismatic orientation; dentin was tested at superficial (DS), middle (DM), and deep (DD) locations. Specimens were tested in tension at 0.5 mm/min.
Main Results:
- UTS values (MPa) were: DEJ, 46.9; EP, 42.1; ET, 11.5; DS, 61.6; DM, 48.7; DD, 33.9.
- Enamel tested transversally to its prisms (ET) was significantly weaker than other enamel and dentin configurations (p < 0.05).
- Dentin's UTS was significantly affected by depth (p < 0.05), with superficial dentin (DS) being the strongest. DEJ UTS was comparable to EP and DM.
Conclusions:
- The ultimate tensile strength of dental structures is not uniform and significantly depends on the tissue type, its location within the tooth, and its structural orientation.
- These findings have implications for understanding failure modes in dental restorations and for the design of adhesive interfaces.