Chemical and mechanical properties of snake fangs

Abstract

The composition of dental tissues and their interaction determines its mechanical properties. The mechanical properties and chemical composition of the teeth of extant reptiles are still poorly studied areas. As a preliminary study the fangs of four species of snakes and a human tooth were investigated through nanoindentation and Raman spectroscopy. The average elastic modulus values for the main body of the fangs ranged from 15.3 GPa to 24.6 GPa, and 19.1 GPa for the human dentine. Raman spectroscopy and principal component analysis (PCA) showed that snake fangs are similar in composition to human dentine, both of which comprised of hydroxyapatite and an organic matrix. The elastic modulus and hardness data were correlated to the Raman spectra using partial least squares regression (PLS). The spectral features which correlated with the elastic modulus would suggest that elastic modulus is dependent on the relative protein to mineral amounts in the tooth. The form of the phosphate and the relative levels of phosphate to organic components also appear to be governing factors for elastic modulus. The PLS of Raman spectra against the hardness gave very similar results. The small differences between snake fangs and human dentine appeared to be because of carbonate content, with higher levels of carbonate in the human tooth than the snake fangs.Snake fangs should be able to withstand large lateral forces. Human dentine aids in dissipating imposed loads. This similarity in the chemical composition of the snake fangs and human dentine supported the findings of the similarities in mechanical properties, which may be attributed to the similar functional demands of these biocomposites.

Mechanics of snake biting: Experiments and modelling

“…There are also no significant differences between the tip region and the base region of the fang. These values are in agreement with the Young’s modulus (15.3-24.6 GPa) of a few snake species (Jansen van Vuuren et al, 2016)…”

Application of low‐wavenumber Raman spectroscopy to the analysis of human teeth

“…This approach permits a reduction in the number of variables without the concomitant loss of information. Overall, PCA has been shown to be a valuable data analysis tool and has already been successfully applied to process Raman spectra from a range of different dental samples …”

“…Overall, PCA has been shown to be a valuable data analysis tool and has already been successfully applied to process Raman spectra from a range of different dental samples. [12,24,39] Analysis for all four samples was carried out using data from both LWR and MWR regions (both together and separately). First, the more conventionally used MWR region was examined.…”

Recent advances in linear and non‐linear Raman spectroscopy. Part XI

“…As a preliminary study, the fangs of four species of snakes and a human tooth were investigated through nanoindentation and Raman spectroscopy. Further, the elastic modulus and hardness data were correlated to the Raman spectra using partial least squares regression (PLS) where it was found that spectral features which correlated with the elastic modulus suggest that the elastic modulus is dependent on the relative protein to mineral amounts in the tooth . Kumar and co‐workers used Raman spectroscopy in an experimental oral carcinogenesis study to determine abnormal changes in control tissues.…”

“…Further, the elastic modulus and hardness data were correlated to the Raman spectra using partial least squares regression (PLS) where it was found that spectral features which correlated with the elastic modulus suggest that the elastic modulus is dependent on the relative protein to mineral amounts in the tooth. [68] Kumar and co-workers used Raman spectroscopy in an experimental oral carcinogenesis study to determine abnormal changes in control tissues. They concluded that Raman-based in vivo imaging can serve as a promising label-free tool for screening even in the nonhabitue population where conventional screening is shown to be not effective.…”