Identification and Quantification of Dentin/Enamel on Multi-use Diamond-instrument Using Raman-spectroscopy

Objectives: In 2015, the Food and Drug Administration (FDA) published a guidance document providing recommendations to medical/dental device manufacturers on the formulation and scientific validation of reprocessing instructions for reusable instruments. This document stresses the importance of thoroughly cleaning a device as a critical step in proper reprocessing instructions. Furthermore, it recommends that when choosing an appropriate test “soil” for cleanliness validation testing, the test soil chosen should allow at least two clinically-relevant soil components to be quantified. The objective of this study was to use dentin/enamel as a test “soil” component on a multi-use diamond instrument and determine the ability of Raman-spectroscopy to identify and quantify its presence.
Methods: A 1.8mm diameter, round multi-use diamond-instrument (Two-Striper®FG, Premier) was used to remove dentin/enamel from a molar to a depth of about 2mm on the interior of the crown. The instrument was positioned horizontally under a Raman-microscope (XploRa-Plus,Horiba Scientific) and imaged for the presence of dentin/enamel at two angles of view (0°,180°) using a 5X objective and a 532nm laser. Intensity measurements surrounding a Raman-shift wavenumber of 960cm^-1 were taken at approximately every 37µm across the entire projected surface area of the spherical portion of the instrument. The two images were then analyzed for estimated coverage of dentin/enamel by calculating area coverage on the image divided by the total area of the instrument image.
Results: The results show that the total calculated dentin/enamel coverage of the diamond-instrument approached approximately 42% (Figure1) when using this method. This shows that identifying the existence and physical location of dentin/enamel on a multi-use diamond-instrument can be done using Raman-spectroscopy. Estimating mass content of enamel/dentin from area coverage will require further analysis.
Conclusions: In this study it was shown that Raman-spectroscopy can be used to identify and approximate surface coverage of dentin/enamel as a “soil” component on a multi-use diamond-instrument.