Correlation of ultrasound microscopy and Vickers hardness measurements of human dentin and enamel - A pilot study

Mareike Warkentin; Cora Freyse; Olaf Specht; Detlef Behrend; Reinhard Maletz; Ralf Janda; Peter Ottl

doi:10.1016/j.dental.2018.03.020

Correlation of ultrasound microscopy and Vickers hardness measurements of human dentin and enamel - A pilot study

Dent Mater. 2018 Jul;34(7):1036-1040. doi: 10.1016/j.dental.2018.03.020. Epub 2018 Apr 17.

Authors

Mareike Warkentin¹, Cora Freyse², Olaf Specht³, Detlef Behrend¹, Reinhard Maletz¹, Ralf Janda⁴, Peter Ottl²

Affiliations

¹ Department of Materials Science and Medical Engineering, Friedrich-Barnewitz-Strasse 4, 18119 Rostock, University of Rostock, Germany.
² Department of Prosthodontics and Materials Science, Strempelstrasse 13, 18057 Rostock, University of Rostock, Germany.
³ Institute of ImplantTechnology and Biomaterials e.V., Rostock, Friedrich-Barnewitz-Strasse 4, 18119 Rostock, Germany.
⁴ Dept. of Operative and Preventive Dentistry and Endodontics, Centre of Dentistry, Medical Faculty, Heinrich-Heine-University, Moorenstraße 5, Geb. 18.13, D-40225 Düsseldorf, Germany. Electronic address: Ralf.Janda@uni-duesseldorf.de.

PMID: 29678330
DOI: 10.1016/j.dental.2018.03.020

Abstract

Objective: To investigate if Vickers microhardness of dentin and enamel correlated with acoustic velocity c(l) or acoustic reflection from the sample's top (amplitude).

Methods: Eight transversal sections of a sound human tooth were investigated with scanning acoustic microscopy (SAM) and Vickers microhardness measurements. Longitudinal acoustic velocity c(l), amplitude and microhardness MHV were evaluated and for each c(l) test point corresponding amplitude and MHV were linearly interpolated and graphically analyzed. Spearman rank order correlation (r_S) was calculated (p<0.05).

Results: c(l) was predominantly 6100-7000ms^-1 in enamel and 3800-4600ms^-1 in dentin and correlated significantly with MHV with 27-420 in enamel and 20-90 in dentin (r_s=0,57). Amplitudes significantly correlated with MHV, too, but even better (r_s=0,77).

Significance: Acoustic velocity and amplitudes were appropriate to detect microhardness differences of dentin and enamel and certain value ranges of both could be assigned to certain MHV ranges. Further research is needed to differentiate more precisely between the different hard tooth tissues.

Keywords: Acoustic; Dentin; Enamel; Imaging; Microscopy; Ultrasound; Vickers hardness.

MeSH terms

Dental Enamel / physiology*
Dental Enamel / ultrastructure*
Dentin / physiology*
Dentin / ultrastructure*
Hardness Tests
Humans
In Vitro Techniques
Microscopy, Acoustic*
Pilot Projects