Preliminary study on the influence of molar crown central region microstructure on the bending strength of dentin
LIU Qing
HOU Tie-zhou
TAO Hong
HOU Si-yu
Ma Jing
SHI Xin
Abstract：AIM:To study the influence of the internal microstructure of molar crown central region on ben-ding strength.METHODS:40 extracted third molars were cut into pieces at the DEJ,superficial dentin,middle den-tin and deep dentin were respectively cut using a sliding microtome to make rectangular beams of 1 mm ×1 mm × 1 0 mm.The bending strength of 1 0 specimens at each tested region was measured by three point bending test.The mi-crostructure of the fractured specimens was observed by SEM,and the relationships between the microstructure and the bending strength was analyzed.RESULTS:The superficial dentin has the highest bending strength,followed by the middle dentin,the DEJ and the deep dentin(between DEJ and the middle dentin,P >0.05,between each 2 parts of others,P <0.05).SEMobservation showed that the dentin tubule density increased from the superficial dentin to the deep dentin.Crack was observed in most DEJ specimens in the nearby enamel.Connection of mutual penetration of collagen fibers from dentin into the enamel was in observed in DEJ.CONCLUSION:The bending strength of dentin correlates negatively with the dentin tubule density.The penetration of collagen fiber in DEJ may be one factor that can restrain the crack propagation.
Keywords：molar crown central regiondentinmicrostructurebending strength
Publication Date：2016-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：4( 17-20 )