The relationship between dentin microhardness and tubule density

Abstract

Pashley D, Okabe A, Parham P. The relationship between dentin microhardness and tubule detisity. Endod Dent 'Frautnatol 1985; 1: 176-179. Abstract -The purpose of this study was to determine the possible eorrelation between dentin microhardness and dentin tubule density in normal human permanent teeth. A new technique was developed whieh permitted serial determinations of the tnierohardness and tubule density of the same group ol titbules, beginning tiear to the detititio-etiamel junctioti and progressitig to the pul|i ehamber. I'lie results show that there is a highly statistically significant inverse eorrelation between dentin microhardness and tubular density. 'Fubular density increased as the pulp ehamber was approached. Fliis was associated with a decrease in dentin mierohardness, presutnably due to a decrease in the amount of intertubular detitin atid an iticrease iti iticlividttal tubular diameter.

Microhardness of superficial and deep sound human dentin

“…20 -25 KHN) for deep dentin. 16,24,25 Such differences are attributed to the mode of specimen preparation. Our values were taken as an average of indentations made on the entire surface of a disc obtained from deep dentin.…”

“…Because the Knoop microindentation technique provides only an average hardness of the surface and is unable to detect variances in the hardness of such individual structures, the variation observed reflects differences in the tubule density at different locations, 24 or in the bulk chemical composition of dentin. Kinney et al, 26 by means of a modified atomic force microscope, showed that the decrease in hardness as a function of depth was caused by a decrease in the stiffness of intertubular dentin matrix due to a heterogeneous distribution of the mineral phase within the collagen matrix.…”

“…Pashley et al prepared much thinner sections of the crowns and made indentations right next to the pulp horns. 24 Fusayama et al calculated a KHN of 20 at an approximate distance of 100 m from the pulp. Their measurements were made on longitudinal sections.…”

Farkli Konsantrasyonlarda Kullanilan Fi̇ti̇k Asi̇t Solüsyonlarinin Kök Kanal Denti̇n Mi̇krosertli̇ği̇ Üzeri̇ndeki̇ Etki̇leri̇

“…Knoop mikrosertlik yöntemi kullanılarak diş sert dokularında ölçüm yapılan çalışmalar vardır. 16 Bu çalışmanın sonuçlarına göre, tüm deney gruplarında mikrosertlikte azalma görülmüştür. Distile su ve %5 NaOCl gruplarında izlenen azalma anlamlı değildir.…”

Son yıkamada kullanılan %5 ve %17 EDTA çözeltilerinin smear tabaka ve debriz uzaklaştırma etkinliklerinin ve dentin mikrosertliğine etkilerinin karşılaştırılması: in vitro çalışma

“…This finding can be explained by the increased tubular diameter and density, and reduced amount of intertubular dentin, as the pulp chamber is approached. 23 Dentinal microhardness was significantly reduced only at the deep-dentin layer (1500 µm) when 17% EDTA was used. This result was probably due to an agentsubstrate relationship, as the EDTA found a greater proportion of inorganic matter (calcium ions) to react with in the deeper parts of the dentin.…”