Fluorescence spectroscopy of teeth and bones of rats to assess demineralization: In vitro, in vivo and ex vivo studies

•Mineral features of teeth and bones may have been modified by a variety of metabolic changes, such as osteoporosis.•Is possible to measure changes in teeth and bone by the fluorescence spectroscopy?•The 532 nm laser for excitation allowed access hard tissue altered, including osteoporosis.•The findings corroborate those obtained by micro energy-dispersive X-ray fluorescence spectrometry (μ-EDXRF).

This study investigated the effects of demineralization on teeth and bones evaluated by fluorescence spectroscopy and micro energy-dispersive X-ray fluorescence spectrometry (μ-EDXRF) in rats. For in vitro study, 20 teeth of Wistar rats were removed and decalcified to evaluate fluorescence. For in vivo study, 10 female Wistar rats aged 6 months were randomized into 2 groups: Control Group (C): non-ovariectomized rats; Ovariectomy Group (OV): ovariectomized rats to induce osteoporosis. The fluorescence spectroscopy of the teeth was performed for long-term (until 180 days). For ex vivo study, the tooth and femur bone of the Wistar rats were removed at 180 days to perform fluorescence spectroscopy using excitation laser at 408 and 532 nm and μ-EDXRF for calcium (Ca) and phosphorus (P) analysis. There were no intergroup differences in fluorescence spectra with laser at 408 nm (p ≥ 0.05), but there were changes in the fluorescence spectra using laser at 532 nm which led to both the wavelength shift and changes in the band area (p < 0.05). The concentrations of P and Ca for the dentine and cortical bone, respectively, were significantly reduced in OV (p < 0.05). Demineralization leading to loss of tissue quality may be assessed by fluorescence spectroscopy using 532 nm laser. These findings corroborate those obtained by μ-EDXRF.

Graphical AbstractDownload full-size image