An ex vivo comparison of near-infrared Raman spectroscopy and cone beam computed tomography in the assessment of bone, dental hard tissues, and bone graft materials.

Objective: To evaluate the potential of near-infrared Raman spectroscopy (RS) in distinguishing between various types of bone, dental hard tissues, and bone graft materials, and to determine the correlation between pixel intensity values (PIVs) in cone beam computed tomography (CBCT) and Raman values.

Study design: A thinly sliced section of mandible was utilized to evaluate cancellous and cortical bone. Extracted human teeth were used to prepare the enamel and dentin samples. Bone graft materials were tested by compacting them into edentulous tooth sockets in a dry human mandible. CBCT and RS scans of the samples were performed. The following RS outcomes were evaluated: 960 cm^-1 phosphate peak location and width, carbonate:phosphate ratio, mineral:matrix ratio, and collagen coiling ratio. One-way ANOVA and primary component analysis (PCA) statistics were used to assess RS outcomes.

Results: The 960 cm^-1 phosphate peak location was able to effectively differentiate between various tissues and graft materials. PCA of the spectra successfully differentiated native bone from graft materials, underscoring the tissue characterization capability of RS. Varied correlations between RS outcomes and CBCT PIVs were observed.

Conclusions: Various parameters of RS can differentiate between cancellous bone, cortical bone, dental hard tissues, and bone graft materials. The varied correlations between Raman parameters and CBCT PIVs warrant further research to clarify the nature of these relationships.