Validation of the Use of ATR Mode in FT-IR Spectroscopy on Gingival Crevicular Fluid Samples in Orthodontics

Previous work has demonstrated the relevance of Fourier Tr and IR investigation on gingival crevicular fluid (GCF) for monitoring orthodontic treatments. Previously, FT-IR spectra of GCF samples have been acquired in reflectance mode by dropping a few microliters of GCF on a reflecting support. A faster procedure for collecting GCF spectra can be obtained by exploiting the Attenuated Total Reflection (ATR) contact sampling method, which allows the collection of goodquality infrared spectra with almost no sample preparation. The objective of the present investigation is to validate the ATR approach for GCF analysis by comparing the spectra acquired in reflectance using the GCF samples extracted via paper cones versus those directly collected from the blotter, employing the ATR approach.