Chemical characterization of lased root surfaces using Fourier transform infrared photoacoustic spectroscopy

Recently lasers have been recommended as an alternative or adjunctive therapy in the control and treatment of periodontally diseased root surfaces. The purpose of this in vitro investigation was to characterize the chemical structure of lased root surfaces using Fourier transform infrared photoacoustic spectroscopy (FTIR/PAS). Cementum samples, 6 mm x 2 mm, were cut from the root surface of extracted non-carious, unerupted human molars. The experimental samples were lased with a Nd:YAG laser at an average energy of 80 mJ at 10 pulses per second. Total lasing time ranged from 1 minute 45 seconds to 4 minutes. A non-lased cementum sample served as the control. All spectra were recorded from 4000 to 400 cm-1 using the photoacoustic cell attachment on an Analect RFX-65 FTIR Spectrometer. Photoacoustic FTIR spectra of lased cementum samples showed a decrease in the protein/mineral ratio in comparison to the control. Breakdown of protein at the root surface potentially contributed to an ammonium band at 2010 cm-1. The decreased protein/mineral ratio and the potential surface contamination with protein by-products, may ultimately affect cell reattachment at the cementum surface.